Taxonomy

Cholevinae is a subfamily of Leiodidae (Coleoptera: Staphylinoidea) (Cai et al. 2022). Previously, it has also been considered a family of its own (Schilthuizen et al. 2011). The taxonomy and synonymy of Perreau is used (Perreau 2000), in combination with https://cholevidae.myspecies.info/ and with updates from more recent taxonomic literature. The distribution of species is based on Perreau (2000, pers. comm.) as well, unless stated otherwise. For the list of species occurring in the Netherlands, the Nederlandse Soortenregister is used (Creuwels & Pieterse 2024). See Fig. 1 for an overview, and Table 1 for the full list of species.

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The subfamily is divided into seven tribes, of which five are included in this analysis (Fig. 1). The two remaining tribes, Sciaphyini and Eucatopini, are relatively small and were not included, as no literature or material was available on their larval morphology. Of the five tribes that are included, Leptodirini is the most speciose and has the most extensively described larval morphology. However, as only a single species occurs in the Netherlands, no material was available of this taxon, and an extensive comparative analysis of other species in the group had already been carried out (Deleurance-Glaçon 1963), only the tribe is included in the keys and descriptions, without a distinction between further subtaxa.

Examined material

Material from Naturalis Biodiversity Center was examined. The specimens were collected by Peter Zwick and Wolfgang Zimmermann in Germany in the 1960s and by Menno Schilthuizen in the Netherlands in the 1980’s, mostly from baited traps but also in bird and mole nests and on carrion. Of the individuals found on carrion, Catops was found mostly on mammals and birds, whereas Ptomaphagus, Nargus Thomson, 1867, and others were also found on other vertebrate carrion. A large part of these specimens was caught as adults, and could therefore be reliably identified to species. From these adults, larvae were then raised. Some specimens were caught as larvae, and the identification of those specimens is therefore less precise (see Discussion) or less accurate, being only identified to subfamily or genus level.

The examined material was preserved as microscope slides of whole larvae and larval exuviae, for a large part in Euparal or Canada balsam. Though most microscope slides contained a single individual, around a third contained multiple individuals, sometimes of different species. Around a fifth of the slides were created in 2015 by students of Menno Schilthuizen (Pinto 2015, Renkens 2015). Some additional material was preserved in 70% ethanol. A cursory examination revealed much of the material belonged to species for which enough material was already available as microscope slides. The material was not examined further due to time constraints and is not included in this analysis.

The specimens were photographed with a Leica DFC450 digital camera on a Leica DMRBE trinocular microscope, using LAS X Core software (Leica Camera AG, Wetzlar, Germany), which recorded the scale of the images. From these images, illustrations were made in Inkscape. Features of dorsal and ventral surfaces were generally drawn in the same illustration, in which case the ventral features were drawn with dotted lines.

In the same LAS X Core software, the sizes of certain morphological features were also measured in Catopina and certain Choleva species. Total body length or head length could not be measured directly as the material consists of a mix of exuviae and whole larvae, and in many cases the abdomen and the head capsule were strongly deformed or contracted by the preparation process. For an indicator of total size, instead the lengths of the three antennomeres and the posterior femur, tibia, and tarsungulus were measured. Especially the second antennomere and the tibia can be measured consistently and can be related to overall size, though it should be noted this cannot be compared between Catopina and Choleva as relative appendage lengths differ. To validate the identifying characteristics of Catopina, the lengths of abdominal tergite X and urogomphomere I were measured. Abdominal tergite X often appeared to start under tergite IX and was measured from there to the carina just after setae pair D1 (Kilian & Mądra 2015, see Figs 52 and 55 below). To validate characteristics in the key to species of Catopina, the length of the dorsal medial seta and ventral apical seta on urogomphomere I were measured and related to the total length of the urogomphomere. Additional species or species group characteristics were explored by measuring the length of urogomphomere II and its apical seta. Additional measurements were made in 2015 (Pinto 2015, Renkens 2015), but were not always usable as the instar of the larvae was not always recorded and not many individuals were measured.

Literature

Literature searches were first performed in Google Scholar and similar platforms. Based on this initial set, supplemented by 5–10 articles known to be relevant, additional literature was found by systematically going through the reference lists of found articles. For a taxonomy-based index of the literature, see Table 1.

Descriptions

The identification keys and descriptions were written using the morphological terminology and the chaetotaxy system used by Kilian (1998, 2007, 2012), with special reference to the description of Sciodrepoides watsoni (Spence, 1815) using that terminology and system (Kilian & Mądra 2015).

Abbreviations used in key, descriptions, and figures are as follows:

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Prostheca vs retinaculum. The terms “prostheca” and “retinaculum” are used inconsistently in the literature, and this is regularly acknowledged by the authors themselves. Jeannel is the first to use both terms in the description of a single Cholevinae species, and uses “retinaculum” for the thin, bristle- or tooth-like appendage (depending on the species) on the inner edge of the mandible and “prostheca” for the sometimes absent broad tooth between the retinaculum and the mola (Jeannel 1911, 1922). This seems to follow the terminology used by Schiødte (1861), who uses “retinaculum” in the same way as Jeannel but who does not describe a prostheca.

Other authors, however, reverse these terms, and use “prostheca” for the bristle- or tooth-like appendage instead (Böving & Craighead 1930, Menozzi 1939, Paulian 1941). Böving and Craighead (1930, pp. 83–84) define “prostheca” and “retinaculum” as follows:

Krogerus (1927) only uses “retinaculum”, in the same way as Böving and Craighead, and instead uses “Zahn” for the “prostheca”. Strouhal circumvents the issue by using “Zahn” for both features (Beier & Strouhal 1928).

In later years, the usage of Böving and Craighead seems more prevalent (Zwick 1978, Kilian 2007, Kilian & Mądra 2015, Kilian & Newton 2017, 2021). This usage seems to be compatible with Lawrence (1991), who also acknowledges the present confusion, albeit without specific reference to these authors. Because of this, and because the terminology used by Jeannel, Deleurance, Franciscolo, and Strambi can be traced back to a single source, this work uses the currently prevalent terminology.

Development

Generally, species of Cholevinae go through three larval instars (L1, L2, and L3). The larvae increase in size between instars (Fig. 2). Additionally, secondary setae develop between L1 and L2. Zwick (1978) lists several differences between the instars: (1) differences in size, (2) differences in chaetotaxy and (for Catopina) the shape of the mandible, (3) antennomere II not polytrichic (except D. umbrina and Catops picipes (Fabricius, 1787)), and (4) a straight paracercal seta (except D. umbrina and certain Catops). However, these differences are all either variable between species (size, chaetotaxy, mandible shape), or have many exceptions. A more general characteristic is also presented, in that in L1, the tergites I–VIII have “eight chaeta”. As opposed to the former characteristics, this one seems to apply to all the L1 material seen by the author, with a few caveats listed in the key to instars below.

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Size progression across instars in Catopina species, based on the lengths of the posterior femur, the posterior tibia, and URI. – The red lines indicate the size progression of C. neglectus, with specimen II.52 interpreted as L2 (solid) or L3 (dashed).

Citation: Tijdschrift voor Entomologie 167, 1-3 (2024) ; 10.1163/22119434-bja10033

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The Leptodirini are an exception to this, with many species only going through two or even just one larval instar before pupating (Deleurance-Glaçon 1963). In all the species found to have just one or two larval instars, Deleurance-Glaçon (1963) found the first of these instars to be equivalent to L1 in other Cholevinae based on chaetotaxy, as opposed to L3 or L2 respectively. However, in those species L1 (and L2, where applicable) is generally larger than the same instar in species with more instars (Fig. 3).

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Size progression across instars in Leptodirini species, based on total body length data from the literature (Deleurance-Glaçon 1963, Decou & Juberthie 1969, Sendra et al. 1985, Adamczyk et al. 2011). – Line and point colours indicate the number of larval instars that the species goes through.

Citation: Tijdschrift voor Entomologie 167, 1-3 (2024) ; 10.1163/22119434-bja10033

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In some Catopina species the antennae and legs are relatively elongated and straight-edged in L3 compared to L2. Some species already have these secondary setae and elongated antennae and legs in L1, making the determination of larval instars difficult without already knowing the exact species. Similarly, in smaller species the change in shape of the antennae and legs is not observed. At first glance, Catops neglectus Kraatz, 1852 might represent a possible exception among Catopina. Based on L1, it seems to be a small species, of similar size to Catops coracinus Kellner, 1846 and Fissocatops westi (Krogerus, 1931). However, the specimen labelled L2 (II.52 = RMNH.INS.967946) is relatively very large (Fig. 2). Leg shape is more indicative of L2, but as seen in other small species this is not a consistent characteristic. Based on trends of size in Leptodirini species with one or two larval instars, it seems improbable that this is also the case in C. neglectus, and as such the specimen has been interpreted as L3 instead.

Morphology

Head

The head consists of the head capsule, a pair of antennae, the labrum, the mandibles, the maxillae, and the labium. The head capsule may have one or more pairs of ocelli, usually behind the antennae, but certain troglobitic species have none. The mandibles often have mola, as well as a retinaculum, a prostheca, both, or neither. The maxillae consist of a stipes and lacinia and have a three-segmented palp. These segments are numbered MPI, MPII, and MPIII. The labium consists of the submentum, mentum, prementum, ligula, and two-segmented labial palps (Fig. 4).

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Head of the larva of Catops morio (Fabricius, 1787), dorsally, schematically coloured to indicate different parts of the morphology. – Antennae in red, head capsule in orange, labrum in yellow, mandibles in green, maxillae in blue, and labium in purple.

Citation: Tijdschrift voor Entomologie 167, 1-3 (2024) ; 10.1163/22119434-bja10033

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Antennae. Instar I — Antennae consist of three segments (antennomeres), numbered AI, AII, AIII from the basal to the distal end, with AII being the largest one. In larger species, AIII is generally shorter relative to AII compared to in smaller species. AI usually has 4–5 campaniform sensilla (c.s.), two dorsally in the basal half of the segment, and 2–3 along the distal edge. AII usually has dorsally a campaniform sensillum and a large seta, laterally a large sensory appendage (SA), and ventrally two large setae and two sensilla (IIs1 and IIs2), respectively “peg-like” and setiform. AIII has subapically four setae, three large and one small, a campaniform sensillum or a small SA next to the small seta, and apically a central “peg-like” sensillum (IIIs1) and a setiform one (IIIs2). Across species, additional setae may occur on AI and AII. Several Catopina species have a single additional seta on AI, and some Choleva species have varying amounts of additional setae on AI and AII. Some species also have microtrichia or microsetae, mainly on AII and AIII. In addition, in some species the antennae, specifically AI and AII, are polytrichic even in instar I. Leptodirini have an additional, long, setiform appendage on AIII, between the four subapical setae and the two apical sensilla. In several Leptodirini species, AIII features a characteristic pigmented band.

Instar II — In instar II and instar III, AI and AII gain secondary setae that are not present in instar I. The number of secondary setae is variable and differs between individuals and between antennae of the same individual. The microtrichia and microsetae on AII are sometimes lost in instars II and III.

Instar III — In instar III, the shape of AIII changes in many Catopina species, with straight edges and the segment being widest at the base of the SA. Several species that have additional setae in instar I, including C. picipes, have that shape in all instars.

Thorax

The thorax consists of the prothorax, mesothorax, and metathorax, each with a pair of legs. All three segments are similar, but the prothorax has a more extensive chaetotaxy. The legs consist of a coxa, a trochanter, a femur, a tibia, and a tarsungulus. The legs are also similar, though the hind legs are generally slightly longer.

Abdomen

The abdomen consists of 10 abdominal segments. Abdominal segments I–IX each have two sclerites, one dorsal and one ventral. The spiracle is located on the posterior margin of the dorsal sclerite, similar in position to those in the larvae of Nodynus leucofasciatus Lewis, 1879 (Coleoptera: Silphidae), where the epipleurite is nonetheless a distinct sclerite in the first abdominal segments (Zaitsev & Tokareva 2021). Here, the dorsal sclerite seems to result from the merging of the tergite, the precoxa, and the epipleurite (see Deuve 2018). The first eight tergites are generally very similar to each other in chaetotaxy, though the shape and length of setae in the posterior row can differ. The chaetotaxy of the sternites is relatively conserved across species. Abdominal segment IX has a different, simpler chaetotaxy but also has a pair of urogomphi and a pair of paracercal setae (Dl3). Abdominal segment X is reduced even further and ends in an anal membrane.

Urogomphi. Instar I — The urogomphi consist of two segments (urogomphomeres), URI and URII. Across Cholevinae, the chaetotaxy of urogomphomere I is fairly conserved, and the main variation comes down to the relative length of the setae and the relative position of the medial dorsolateral seta, which can be located dorsally or laterally, from the proximal half to the distal end of the segment. In addition to the medial dorsolateral seta, most species have seven other setae: five proximal setae, of which three dorsal, one lateral, and one ventral; and two distal setae, one dorsal and one ventral. An exception are the Ptomaphagini, which have a shorter urogomphomere I with only six setae, and some of the Leptodirini, which also can have reduced urogomphi. In addition to the eight setae, urogomphomere I generally has five campaniform sensilla, all dorsolateral: two proximal, one medial, and two distal. A known exception occurs in Anemadini, where an elliptical structure similar to the medial sensillum can be found in largely the same location, albeit more distal; whether this structure is homologous to the medial sensillum is unclear. The two distal sensilla are usually adjacent, lined up in the direction of the urogomphomere, with the more distal of the pair appearing to be located on urogomphomere II. In all cited literature, both are considered to be located on urogomphomere I. Whereas Ptomaphagini do have all five campaniform sensilla, not all Leptodirini do, even in the less specialized species (Deleurance-Glaçon 1963). The chaetotaxy of urogomphomere II is trivial, consisting of a single apical seta in almost all species, bar a few specialized troglobitic species in Leptodirini.

Instar II and III — The chaetotaxy of URI and URII is generally conserved in later instars, though the relative lengths of the medial dorsolateral seta and the ventral distal seta may differ.

Diagnosis

Inner edge of the mandible straight, mandibles asymmetrical (Fig. 5). URI at most 1.5 times as long as abdominal segment X, URII 3–5 times as long as URI.

Instar I: Prostheca pointed, simple.

Distribution

Throughout Europe.

Diagnosis

AIII with 2 apical sensilla and 4 setae, as well as 1 subapical campaniform sensillum. URI at most 1.5 times as long as abdominal segment X. URI with 8 setae. URII at most 3 times as long as URI. Apex of mandible long, curved, and pointed, and inner edge of mandible concave (L1); or inner edge of mandible straight (L2, L3). In L3, the galea is reduced from a double fringe to a simple brush shape (Fig. 31) or a singular fringe.

Key to the species of larval instar I of Catopina

The phylogeny of Cholevini species presented in 2016 (Schilthuizen et al. 2016) has been used as a rough guideline for the construction of this key, though the exact structure has been changed to improve the usability.

1. 1.URI 2–3 times as long as abdominal segment X. URI ventrally with many small setae (Fig. 6). Apex of mandible short; inner edge of mandible straight … Dreposcia umbrina (Erichson, 1837)
2. –URI does not extend or barely extends beyond abdominal segment X. URI ventrally with two setae (Figs 7–11). Apex of mandible long; inner edge of mandible concave ………………… 2
3. 2.Medial seta on URI long, 0.4–0.6 times as long as URI. AI without setae (Figs 32, 35)……… 3
4. –Medial seta on URI less than 0.4 times as long as URI (Figs 7–11), or if more than 0.4 times as long as URI (Catops tristis (Panzer, 1794)), then with a seta on AI (Fig. 36) …………… 6
5. 3.Subapical, ventral seta on URI much longer, 0.8–1 times as long URI. Position of the middle c.s. usually relatively distal. Posterior tibia 170–190 µm…Catops morio (Fabricius, 1787)
6. –Subapical, ventral seta on URI much shorter, 0.15–0.5 times as long as URI. Position of the middle c.s. variable…………………………4
7. 4.Larger species, posterior tibia 200–220 µm. Position of the middle c.s. usually relatively distal. Subapical, ventral seta on URI 0.25–0.5 times as long as URI……………………………… Catops subfuscus Kellner, 1846
8. –Small species, posterior tibia 150–170 µm. Position of the middle c.s. usually relatively proximal. Subapical, ventral seta on URI variable (Sciodrepoides Hatch, 1933)…………………5
9. 5.Subapical, ventral seta on URI short, 0.15–0.25 times as long as URI…………………………………… Sciodrepoides fumatus (Spence, 1815)
10. –Subapical, ventral seta on URI less short, 0.3–0.5 times as long as URI………………………… Sciodrepoides watsoni (Spence, 1815)
11. 6.Tergites on each lateral half with more than 3 setae between anterior carina and P1–P5 of the posterior row (Figs 13, 15, 16); exact amount usually variable between tergites and left/right……………………………………7
12. –Tergites on each lateral half consistently with 3 setae between anterior carina and P1–P5 of the posterior row………………………………9
13. 7.AI and AII polytrichic. P2 of tergites longer than P5. Usually not more than 7 setae between anterior carina and posterior row (Fig. 13)………………Catops picipes (Fabricius, 1787)
14. –AI and AII with normal setae (Fig. 30). P2 of tergites shorter than P5 (Figs 15, 16)………8
15. 8.4–7, usually 5–6 setae between anterior carina and posterior row (Fig. 15). P2 is 0.3–0.5 times as short as P5. P1 and P2 are frayed for one third of the length. Antennomere II dorsally with multiple rows of microtrichia (Fig. 30)…………… Catops grandicollis Erichson, 1837
16. –11–16, usually 13–14 setae between anterior carina and posterior row (Fig. 16). P2 is 0.6–0.7 times as short as P5. P1 and P2 are barely frayed. Antennomere II dorsally without multiple rows of microtrichia ………… ………………… Catops kirbyi (Spence, 1815)
17. 9.Antennomere II with microsetae (Fig. 34). Subapical, ventral seta on URI long, 0.5–1 times as long as URI (Figs 7, 8). Setae Da2–Dc2 on abdominal tergites tubular, with flat or frayed ends: Catops fuscus-group ……… 10
18. –Antennomere II without microsetae (Figs 27–29, 33, 36, 37). Subapical, ventral seta on URI much shorter, up to 0.45 times as long as URI (Figs 9, 11). Setae Da2–Dc2 on abdominal tergites pointed, sometimes shortly frayed; not tubular……………………………………13
19. 10.P1 of tergites shorter than or barely as long as the distance to the anterior carina of the same tergite. Setae P1–P5 with nearly flat ends, only shortly frayed. No seta on AI ……………… …………… Catops nigriclavis Gerhardt, 1900
20. –P1 of tergites longer than the distance to the anterior carina of the same tergite. Setae P1–P5 with frayed ends. AI variable …… 11
21. 11.Smaller species, antennomere II 170–185 µm, posterior tibia 0.26 ± 0.01 mm. No seta on AI ………………… . fuliginosus Erichson, 1837
22. –Larger species, antennomere II longer than 185 µm, posterior tibia longer than 0.29 mm. AI variable ……………………………… 12
23. 12.No seta on AI. Smaller species, antennomere II 185–205 µm, posterior tibia 0.31 ± 0.01 mm ………………… Catops fuscus (Panzer, 1794)
24. –AI with seta (Fig. 34). Larger species, antennomere II 215–225 µm, posterior tibia 0.36 ± 0.01 mm …… Catops nigricans (Spence, 1815)
25. 13.AI with seta. Larger species, posterior tibia 200–250 µm ……………………………   14
26. –AI without seta. Smaller species, posterior tibia 120–200 µm ……………………… 16
27. 14.Medial seta on URI short, 0.15–0.3 times as long as URI. Setae Da2–Dc2 on abdominal tergites tubular, with flat or frayed ends. P2 about as long as P5 ………………………………………… Catops chrysomeloides (Panzer, 1798)
28. –Medial seta on URI longer, 0.3–0.6 times as long as URI. Setae Da2–Dc2 on abdominal tergites with pointed ends. P2 shorter than P5 ………………………………………… . 15
29. 15.P2 on abdominal tergite shorter, 0.3–0.5 times as long as the space between the anterior carina and the posterior edge of the tergite. Antennomere III relatively short, 50–65 µm, 0.3–0.4 times as long as antennomere II (Fig. 27). Posterior tibia longer, 225–245 µm …………………… ………… Apocatops nigrita (Erichson, 1837)
30. –P2 on abdominal tergite longer, 0.75–1 times as long as the space between the anterior carina and the posterior edge of the tergite. Antennomere III relatively long, 65–75 µm, 0.35–0.5 times as long as antennomere II (Fig. 36). Posterior tibia shorter, 200–225 µm …………… ………………… Catops tristis (Panzer, 1794)
31. 16.Antennomere II 90–110 µm (Fig. 29), posterior tibia shorter than 150 µm (usually 120–140 µm) ………… Catops coracinus Kellner, 1846
32. –Antennomere II at least 120 µm (Figs 33, 37), posterior tibia longer than 150 µm (usually 160–180 µm) …………………………… 17
33. 17.Medial seta on URI is 0.1–0.2 times as long as URICatops neglectus Kraatz, 1852
34. –Medial seta on URI is 0.3–0.4 times as long as URI (Fig. 11) …………………………… …………… Fissocatops westi (Krogerus, 1931)

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Urogomphomere I of instar I. – 6, Dreposcia umbrina (Erichson, 1837), with 0.2x scale inset; 7, Catops nigricans (Spence, 1815); 8, Catops fuscus (Panzer, 1794); 9, Apocatops nigrita (Erichson, 1837); 10, Catops grandicollis Erichson, 1837; 11, Fissocatops westi (Krogerus, 1931); 12, Sciodrepoides fumatus (Spence, 1815).

Citation: Tijdschrift voor Entomologie 167, 1-3 (2024) ; 10.1163/22119434-bja10033

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Right half of tergite V of instar I. Certain elements (lateral edge of the tergite, R, Gp) were omitted from the figure when they were not seen, but this does not necessarily imply absence. – 13, Catops picipes (Fabricius, 1787); 14, Dreposcia umbrina (Erichson, 1837), folded in half; 15, Catops grandicollis Erichson, 1837; 16, Catops kirbyi (Spence, 1815).

Citation: Tijdschrift voor Entomologie 167, 1-3 (2024) ; 10.1163/22119434-bja10033

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Key to the species of larval instars II and III of Catopina

1. 1.1. URI at most 1.5 as long as abdominal segment X. URI ventrally with two setae (Figs 7–11) … 2
2. –URI 2–3 as long as abdominal segment X. URI ventrally with many small setae (Fig. 6) ………… Dreposcia umbrina (Erichson, 1837)
3. 2.Prementum with two pairs of setae and one pair of campaniform sensilla ……………… 3
4. –Prementum with two pairs of setae and no sensilla (Fig. 31) ………………………… ……………… Catops morio (Fabricius, 1787)
5. 3.Medial seta on URI long, 0.38–0.6 times as long as URI. Tergites on each lateral half with a posterior row consisting of 5 large setae and 6 smaller setae ……………………………… 4
6. –Medial seta on URI short, up to 0.37 times as long as URI. If longer, posterior row consisting of 4 large setae (Catops tristis (Panzer, 1794)) …………………………………… 6
7. 4.Tergites on each lateral half above the posterior row with 18 setae, arranged in two rows of 9 …………… Catops subfuscus Kellner, 1846
8. –Tergites on each lateral half above the posterior row with 20–30 (L2) or 30–40 (L3) setae, not in two neat rows: Sciodrepoides Hatch, 1933 …………………………………………… 5
9. 5.Faint (L2) or clear (L3) brown spot on head (Figs 18, 19). URII about 1.5 times as long as URI. Galea usually extends beyond tip of maxilla …… Sciodrepoides watsoni (Spence, 1815)
10. –No brown spot on head. URII nearly 2 times as long as URI. Galea usually does not extend beyond tip of maxilla ……………………… ………… Sciodrepoides fumatus (Spence, 1815)
11. 6.AI with 4–6 setae. MPII with 2 setae. Malae with 4 lacinia and dorsally 2–3 additional setae. Mandible with 4–5 setae. Subapical ventral seta short ………………………………… 7
12. –AI polytrichic, with 20+ setae. MPII with 4–5 setae. Malae with 7 lacinia and dorsally 4+ additional setae. Mandible with 6 setae. Labrum with additional pair of setae dorsally. Subapical ventral seta long ………………………… ……………… Catops picipes (Fabricius, 1787)
13. 7.Paracercal setae less than half as long as URI, straight or curved, with frayed ends (Figs 20, 21) ……………………………… 8
14. –Paracercal setae shorter or longer than URI, the base somewhat flattened and then bent, with pointed ends (cf. Figs 22, 23) ……………… 9
15. 8.Tergite on each lateral half with a posterior row of 4 major and 4 minor setae, about 20–25 setae on the rest of the tergite half. Subapical ventral seta on URI relatively proximal …………… …………… Catops grandicollis Erichson, 1837
16. –Tergite on each lateral half with a posterior row of 4 major and 9 minor setae, about 40–50 setae on the rest of the tergite half ………… ………………… Catops kirbyi (Spence, 1815)
17. 9.Subapical, ventral seta on URI long, at least 0.3 times as long as URI (cf. Figs 7, 8): Catops fuscus-group ……………………………… 10
18. –Subapical, ventral seta on URI short, at most 0.25 times as long as URI (cf. Figs 9, 11) … 13
19. 10.AI with 11+ setae. Tergites on each lateral half between the posterior row and anterior carina with more than 40 setae ………………… …………… Catops nigriclavis Gerhardt, 1900
20. –AI with 7–10 setae. Tergites on each lateral half between the posterior row and anterior carina with less than 30 setae …………… 11
21. 11.Mandible with 3 larger and 3 smaller setae. Larger: AII is 310–330 µm (L2) or 380–400 µm (L3) and posterior tibia is 490–510 µm (L2) or 675–700 µm (L3) ………………… ……………… Catops nigricans (Spence, 1815)
22. –Mandible with 3 larger and 4 smaller setae. Smaller: AII at most 290 µm (L2) or 360 µm (L3) and posterior tibia is at most 440 µm (L2) or 600 µm (L3) ……………………… 12
23. 12.Larger: AII is 270–290 µm (L2) or 340–360 µm (L3) and posterior tibia is 420–440 µm (L2) or 550–600 µm (L3) ………………… ………………… Catops fuscus (Panzer, 1794)
24. –Smaller: AII is 240–260 µm (L2) or 300–310 µm (L3) and posterior tibia is 340–370 (L2) or 440–480 µm (L3) ……………………… …………… Catops fuliginosus Erichson, 1837
25. 13.Larger: AII is longer than 185 µm (L2) or longer than 220 µm (L3) and posterior tibia longer than 260 µm (L2) or longer than 335 µm (L3) …… 14
26. –Smaller: AII is shorter than 160 µm (L2) or shorter than 200 µm (L3) and posterior tibia shorter than 240 µm (L2) or shorter than 325 µm (L3) ………………………………… 16
27. 14.Tergites on each lateral half with a posterior row with 5 major setae. P5 shorter than P2 ……… Catops chrysomeloides (Panzer, 1798)
28. –Tergites on each lateral half with a posterior row with 4 major setae. P5 longer than all other seta in the posterior row ……………… 15
29. 15.Tergites on each lateral half between the posterior row and anterior carina with more than 35 setae. URII more than 2.5 times as long as URI ………… Apocatops nigrita (Erichson, 1837)
30. –Tergites on each lateral half between the posterior row and anterior carina with less than 30 setae. URII less than 2.3 times as long as URI ………………… Catops tristis (Panzer, 1794)
31. 16.Medial dorsal seta on URI very short, less than 0.2 times as long as URI. Small, posterior tibia 150–180 µm (L2) or 230–250 µm (L3) ……………… Catops coracinus Kellner, 1846
32. –Medial dorsal seta on URI longer, at least 0.25 times as long as URI ……………………… 17
33. 17.Apical seta on urogomphomere II longer, 65–75 µm, more than 0.2 times as long as urogomphomere II ………………………… ………………… Catops neglectus Kraatz, 1852
34. –Apical seta on urogomphomere II shorter, up to 55 µm, less than 0.2 times as long as urogomphomere II ………………………… …………… Fissocatops westi (Krogerus, 1931)

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Head of Sciodrepoides watsoni (Spence, 1815). – 17, Instar I; 18, Instar II; 19, Instar III.

Citation: Tijdschrift voor Entomologie 167, 1-3 (2024) ; 10.1163/22119434-bja10033

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Paracercal setae of instar III. – 20, Catops grandicollis Erichson, 1837; 21, Catops kirbyi (Spence, 1815); 22, Catops morio (Fabricius, 1787); 23, Catops picipes (Fabricius, 1787).

Citation: Tijdschrift voor Entomologie 167, 1-3 (2024) ; 10.1163/22119434-bja10033

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Diagnosis

Instar I: Antennomere I with a seta (Fig. 27). Antennomere II with typical setae, without microsetae (Fig. 27). P1–P5 on tergites are pointed, but with short frays, and are relatively short, with P2 0.3–0.5 times as long as the tergite; Da2 on tergites pointed. Chaetotaxy of tergites otherwise typical. Medial dorsolateral seta on urogomphi slightly longer than typical, 0.3–0.4 times as long as urogomphomere I (Fig. 9). Distal ventral seta short, 0.1–0.2 times as long as urogomphomere I (Fig. 9).

Instar II & III: Antennomere I with 8 setae. Mandible with 5 setae. Maxillary palpomere II with 2 setae. Tergites between posterior row and anterior carina with more than 35 setae. Medial dorsolateral seta on urogomphi 0.15–0.3 times as long as urogomphomere I. Distal ventral seta short, 0.1–0.2 times as long as urogomphomere I. Urogomphomere I 0.3–0.4 times as long as urogomphomere II.

Distribution

Throughout Europe.

Diagnosis

Instar I: Antennomere I with a seta (Fig. 28). Antennomere II with typical setae, without microsetae (Fig. 28). P1–P5 on tergites are frayed, and are relatively short, P2 0.5–0.7 times as long as the tergite; Da2 on tergites tubular. Chaetotaxy of tergites otherwise typical. Medial dorsolateral seta on urogomphi short, 0.15–0.3 times as long as urogomphomere I. Distal ventral seta short, 0.15–0.3 times as long as urogomphomere I.

Instar II & III: Antennomere I with around 6 setae. Mandible with 4 setae. Maxillary palpomere II with 2 setae. Tergites between posterior row and anterior carina with 20–30 setae. Medial dorsolateral seta on urogomphi 0.15–0.3 times as long as urogomphomere I. Distal ventral seta short, 0.1–0.25 times as long as urogomphomere I. Urogomphomere I 0.5–0.65 times as long as urogomphomere II.

Distribution

Central, western, southern, and eastern Europe, up to Denmark; Turkey; Armenia.

Diagnosis

Instar I: Antennomere I without setae (Fig. 29). Antennomere II with typical setae, without microsetae (Fig. 29). P1–P5 on tergites are frayed, and are relatively short, P2 0.4–0.5 times as long as the tergite; Da2 on tergites pointed. Chaetotaxy of tergites otherwise typical. Medial dorsolateral seta on urogomphi short, 0.15–0.25 times as long as urogomphomere I. Distal ventral seta short, 0.15–0.3 times as long as urogomphomere I.

Instar II & III: Antennomere I with 4 setae. Mandible with 4 setae. Maxillary palpomere II with 2 setae. Tergites between posterior row and anterior carina with 20–25 setae. Medial dorsolateral seta on urogomphi 0.1–0.15 times as long as urogomphomere I. Distal ventral seta short, 0.1–0.2 times as long as urogomphomere I. Urogomphomere I 0.45–0.65 times as long as urogomphomere II.

Distribution

Throughout Europe; North Africa; Middle East; Central Asia.

Diagnosis

Instar I: Antennomere I without setae. Antennomere II with microsetae, setae otherwise typical. P1–P5 on tergites are frayed, and are typical, P2 0.75–1 times as long as the tergite; Da2 on tergites tubular. Chaetotaxy of tergites otherwise typical. Medial dorsolateral seta on urogomphi short, 0.2–0.25 times as long as urogomphomere I. Distal ventral seta long, 0.5–0.8 times as long as urogomphomere I.

Instar II & III: Antennomere I with 7–10 setae. Mandible with 7 setae. Maxillary palpomere II with 2 setae. Tergites between posterior row and anterior carina with 25–30 setae. Distal ventral seta long.

Habitat

Found in mouse nests.

Distribution

Throughout Europe; Middle East.

Diagnosis

Instar I: Antennomere I without setae. Antennomere II with microsetae, setae otherwise typical. P1–P5 on tergites are frayed, and are typical, P2 0.7–1 times as long as the tergite; Da2 on tergites tubular. Chaetotaxy of tergites otherwise typical. Medial dorsolateral seta on urogomphi short, 0.1–0.25 times as long as urogomphomere I (Fig. 8). Distal ventral seta long, 0.6–0.9 times as long as urogomphomere I (Fig. 8).

Instar II & III: Antennomere I with 7–10 setae. Mandible with 7 setae. Maxillary palpomere II with 2 setae. Tergites between posterior row and anterior carina with 25–30 setae. Distal ventral seta long.

Distribution

Throughout Europe; Western Siberia.

Diagnosis

Instar I: Antennomere I with a seta (Fig. 30). Antennomere II dorsally with multiple rows of microtrichia, setae otherwise typical (Fig. 30). P1–P5 on tergites are short, broad, and frayed for one third of the length, P2 0.05–0.2 times as long as the tergite; Da2 on tergites pointed (Fig. 15). Between the anterior carina and P1–P5 there are 4–7 setae, usually 5–6, in a single row (Fig. 15). Medial dorsolateral seta and distal ventral seta on urogomphi short (Fig. 10).

Instar II & III: Antennomere I with 4–6 setae. Mandible with 4 setae. Maxillary palpomere II with 2 setae. Tergites between posterior row and anterior carina with 20–25 setae. Paracercal setae curved, not bent. Medial dorsolateral seta on urogomphi short. Distal ventral seta short.

Distribution

Throughout Europe; Turkey.

Diagnosis

Instar I: Antennomere I with a seta. Antennomere II with typical setae, no microsetae. P1–P5 on tergites are short, broad, barely frayed, P2 0.05–0.2 times as long as the tergite; Da2 on tergites pointed. Between the anterior carina and P1–P5 there are 11–16 setae, usually 13–14, in two rows. Medial dorsolateral seta and distal ventral seta on urogomphi short.

Instar II & III: Antennomere I with 4–6 setae. Mandible with 4 setae. Maxillary palpomere II with 2 setae. Tergites between posterior row and anterior carina with 40–50 setae. Paracercal setae curved, not bent. Medial dorsolateral seta on urogomphi short. Distal ventral seta short.

Distribution

Central, western, and southern Europe; Caucasus; Central Asia.

Diagnosis

Instar I: Antennomere I without setae (Fig. 32). Antennomere II with typical setae, no microsetae (Fig. 32). P1–P5 on tergites are frayed, and of typical length, P2 0.8–1 times as long as the tergite; Da2 on tergites pointed. Chaetotaxy of tergites otherwise typical. Medial dorsolateral seta long, 0.4–0.6 times as long as urogomphomere I. Distal ventral seta also long, 0.8–1 times as long as urogomphomere I.

Instar II & III: Antennomere I with 6 setae. Mandible with 4 setae (Fig. 25). Maxillary palpomere II with 2 setae (Fig. 31). Tergites between posterior row and anterior carina with 18 setae. Medial dorsolateral seta on urogomphi 0.25–0.4 times as long as urogomphomere I. Distal ventral seta 0.35–0.55 times as long as urogomphomere I. Urogomphomere I 0.45–0.65 times as long as urogomphomere II.

Distribution

Throughout Europe; Siberia; Central Asia.

Diagnosis

Instar I: Antennomere I without setae (Fig. 33). Antennomere II with typical setae, no microsetae (Fig. 33). P1–P5 on tergites have flat ends, are frayed, and relatively short, P2 0.5–0.7 times as long as the tergite; Da2 on tergites pointed. Chaetotaxy of tergites otherwise typical. Medial dorsolateral seta short, 0.1–0.2 times as long as urogomphomere I. Distal ventral seta also short, 0.1–0.25 times as long as urogomphomere I.

Instar II: Unknown.

Instar III: Antennomere I with 6 setae. Maxillary palpomere II with 2 setae. Tergites between posterior row and anterior carina with 25–30 setae. Medial dorsolateral seta on urogomphi 0.3–0.4 times as long as urogomphomere I. Distal ventral seta 0.05–0.2 times as long as urogomphomere I. Urogomphomere I 0.6–0.7 times as long as urogomphomere II.

Distribution

Throughout Europe.

Diagnosis

Instar I: Antennomere I with a seta (Fig. 34). Antennomere II with microsetae, setae otherwise typical (Fig. 34). P1–P5 on tergites are frayed, and are typical, P2 about as long as the tergite; Da2 on tergites tubular. Chaetotaxy of tergites otherwise typical. Medial dorsolateral seta on urogomphi short, 0.15–0.25 times as long as urogomphomere I (Fig. 7). Distal ventral seta long, 0.8–1.1 times as long as urogomphomere I (Fig. 7).

Instar II & III: Antennomere I with 8–9 setae. Mandible with 6 setae. Maxillary palpomere II with 2 setae. Tergites between posterior row and anterior carina with 20–30 setae. Distal ventral seta long.

Distribution

Central and western Europe; Northern Asia up to China.

Diagnosis

Instar I: Antennomere I without setae. Antennomere II with microsetae, setae otherwise typical. P1–P5 on tergites have flat ends, are frayed, and are short, P2 about half as long as the tergite; Da2 on tergites tubular. Chaetotaxy of tergites otherwise typical. Medial dorsolateral seta on urogomphi short, 0.10–0.25 times as long as urogomphomere I. Distal ventral seta long, 0.4–0.9 times as long as urogomphomere I.

Instar II & III: Antennomere I with 11 setae. Mandible with 7 setae. Maxillary palpomere II with 2 setae. Tergites between posterior row and anterior carina with 40–50 setae. Distal ventral seta long.

Habitat

Found in mole nests.

Distribution

Throughout Europe; Armenia; Iran; Central Asia.

Diagnosis

Instar I: Antennomeres I and II polytrichic, each with multiple additional setae. Antennomere II also with microsetae. P1–P5 on tergites are long and frayed, P2 about as long as the tergite; Da2 on tergites variable, usually pointed but tubular on anterior tergites (Fig. 13). Between the anterior carina and P1–P5 there are 5–7 setae, usually 6–7, in a single row (Fig. 13). Medial dorsolateral seta on urogomphi short, distal ventral seta on urogomphi relatively longer than typical.

Instar II & III: Antennomere I with more than 20 setae. Mandible with 6 setae. Maxillary palpomere II with 4–5 setae. Tergites between posterior row and anterior carina with around 20 setae. Paracercal setae bent. Medial dorsolateral seta on urogomphi short. Distal ventral seta longer.

Habitat

Found in mouse nests, oak tree hollow.

Distribution

Central and western Europe.

Diagnosis

Instar I: Antennomere I without setae (Fig. 35). Antennomere II with typical setae, no microsetae (Fig. 35). P1–P5 on tergites are frayed, and of typical length, P2 0.75–1 times as long as the tergite; Da2 on tergites pointed with frays. Chaetotaxy of tergites otherwise typical. Medial dorsolateral seta long, 0.4–0.5 times as long as urogomphomere I. Distal ventral seta also long, 0.25–0.5 times as long as urogomphomere I.

Instar II & III: Antennomere I with 4–6 setae. Mandible with 4 setae. Maxillary palpomere II with 2 setae. Tergites between posterior row and anterior carina with 18 setae. Medial dorsolateral seta on urogomphi 0.45–0.55 times as long as urogomphomere I. Distal ventral seta 0.15–0.3 times as long as urogomphomere I. Urogomphomere I 0.4–0.55 times as long as urogomphomere II.

Distribution

Europe, except British Isles; Armenia.

Diagnosis

Instar I: Antennomere I with a seta (Fig. 36). Antennomere II with typical setae, without microsetae (Fig. 36). P1–P5 on tergites are frayed, and are of typical length, P2 0.75–1 times as long as the tergite; Da2 on tergites pointed. Chaetotaxy of tergites otherwise typical. Medial dorsolateral seta on urogomphi relatively long, 0.35–0.55 times as long as urogomphomere I. Distal ventral seta short, 0.1–0.4 times as long as urogomphomere I.

Instar II & III: Antennomere I with 7 setae. Mandible with 4 setae. Maxillary palpomere II with 2 setae. Tergites between posterior row and anterior carina with 20–25 setae. Medial dorsolateral seta on urogomphi 0.25–0.35 times as long as urogomphomere I. Distal ventral seta 0.1–0.2 times as long as urogomphomere I. Urogomphomere I 0.4–0.65 times as long as urogomphomere II.

Distribution

All of Europe.

Diagnosis

Instar I: Apex of mandible short. Antennomeres I and II polytrichic, each with multiple additional setae. P1–P5 on tergites are short and pointed, P2 0.1–0.3 times as long as the tergite; Da2 on tergites pointed (Fig. 14). Between the anterior carina and P1–P5 there are 7–12 setae, usually 8–9, in three rows (Fig. 14). Urogomphomere I polytrichic, especially ventrally; long, 2–3 times as long as abdominal segment X (Fig. 6). Medial dorsolateral seta on urogomphi short (Fig. 6). Distal ventral seta on urogomphi very long, about two thirds of the length of urogomphomere II (Fig. 6).

Instar II & III: Antennomere I with around 30 setae. Mandible with more than 8 setae. Maxillary palpomere II with 2 setae. Tergites between posterior row and anterior carina with 40–50 setae. Paracercal seta straight, short. Urogomphomere I polytrichic. Medial dorsolateral seta on urogomphi short. Distal ventral seta long.

Distribution

Central and western Europe, up to Romania in the east and Denmark in the north.

Diagnosis

Instar I: Antennomere I without setae (Fig. 37). Antennomere II with typical setae, without microsetae (Fig. 37). P1–P5 on tergites are frayed, and are of typical length, P2 0.6–0.8 times as long as the tergite; Da2 on tergites pointed, frayed. Chaetotaxy of tergites otherwise typical. Medial dorsolateral seta on urogomphi relatively longer than typical, 0.3–0.4 times as long as urogomphomere I (Fig. 11). Distal ventral seta short, 0.15–0.2 times as long as urogomphomere I (Fig. 11).

Instar II: Antennomere I with 5 setae. Mandible with 3 setae. Maxillary palpomere II with 2 setae. Tergites between posterior row and anterior carina with 20–25 setae. Medial dorsolateral seta on urogomphi 0.275–0.4 times as long as urogomphomere I. Distal ventral seta 0.05–0.15 times as long as urogomphomere I. Urogomphomere I 0.425–0.5 times as long as urogomphomere II.

Instar III: Unknown.

Distribution

Northern and western Europe.

Diagnosis

Instar I: Antennomere I without setae (Fig. 38). Antennomere II with typical setae, no microsetae (Fig. 38). P1–P5 on tergites are frayed, relatively short, P2 0.5–0.75 times as long as the tergite; Da2 on tergites pointed with frays. Chaetotaxy of tergites otherwise typical. Medial dorsolateral seta long, 0.4–0.6 times as long as urogomphomere I (Fig. 12). Distal ventral seta short, 0.15–0.25 times as long as urogomphomere I (Fig. 12).

Instar II & III: Antennomere I with 6 setae. Mandible with 4 setae. Maxillary palpomere II with 2 setae (cf. Fig. 39). Tergites betwee essen, Schlitz, 30.xi.196 n posterior row and anterior carina with 30–40 setae. Medial dorsolateral seta on urogomphi 0.35–0.55 times as long as urogomphomere I. Distal ventral seta 0.05–0.2 times as long as urogomphomere I. Urogomphomere I 0.35–0.55 times as long as urogomphomere II.

Distribution

All of Europe and Asia, up to Japan.

Nomenclature

The author citation “Spence, 1813” refers to the same publication as “Spence, 1815”, namely that in Transactions of the Linnean Society of London vol. 11, issue 1, pp. 123–160. The cover page of the volume lists the year of publication as 1815, but the first issue may have been published at an earlier date. The author citations used in (Perreau 2000) are used here.

Material examined: Germany [34 ex.]: Berlin, Berlin-Böttcherberg, v.1964, 12 ex. (RMNH.INS.967962); Berlin, Berlin-Tiefwerder, 1963–1964, 1 ex. (RMNH.INS.5069663); n.d., 6 ex. (RMNH.INS.947574); Hessen, Obernhausen Rhön, vii.1960, 1 ex. (RMNH.INS.947573); Hessen, Schlitz, 1966, 11 ex. (RMNH.INS.967953); unknown location, n.d., 3 ex. (RMNH.INS.947572); Netherlands [9 ex.]: Overijssel, Enschede, 01.v.2012, 1 ex. (RMNH.INS.5069666); Zuid-Holland, Katwijk aan Zee, x.1987, 1 ex. (RMNH.INS.5069540); Zuid-Holland, Leiden, 1980s, 7 ex. (RMNH.INS.5069566, RMNH.INS.5069570, RMNH.INS.5069573, RMNH.INS.5069574, RMNH.INS.5069576, RMNH.INS.5069577, RMNH.INS.5069578) [labelled Catops morio].

Diagnosis

Instar I: Antennomere I without setae. Antennomere II with typical setae, no microsetae. P1–P5 on tergites are frayed, of typical length, P2 0.75–1 times as long as the tergite; Da2 on tergites pointed with frays. Chaetotaxy of tergites otherwise typical. Medial dorsolateral seta long, 0.4–0.6 times as long as urogomphomere I. Distal ventral seta relatively long, 0.3–0.5 times as long as urogomphomere I.

Instar II & III: Antennomere I with 5–6 setae. Head dorsally with a brown spot. Mandible with 4 setae. Maxillary palpomere II with 2 setae. Tergites between posterior row and anterior carina with 30–40 setae. Medial dorsolateral seta on urogomphi 0.35–0.55 times as long as urogomphomere I. Distal ventral seta 0.05–0.2 times as long as urogomphomere I. Urogomphomere I 0.35–0.55 times as long as urogomphomere II.

Distribution

All of Europe and Asia; North America.

Diagnosis

Mandibles symmetrical, each with two or four apical teeth. Prostheca frayed, bristle-like.

Key to the genera of Cholevina larvae

Xambeu (1892) describes the larva of Attaephilus arenarius (H. Hampe, 1852) but does not go into enough detail as to determine which instar is being described, and size is too variable between genera to use as a comparison. If it is assumed that the ratio of the length of the first and second segments of the maxillary palps does not differ between instars, as it does not in Choleva and Nargus, Attaephilus Motschulsky, 1870 can be distinguished from other Cholevina by the second segment of the maxillary palps being twice as long as the first, instead of the same size, or at most slightly longer.

Kilian and Newton (2021) describe third-instar larvae of Prionochaeta opaca (Say, 1825), which have a unique morphological characteristic in that antennomere II consists of two separate segments AIIa and AIIb. Since the larvae of the first and second instars are unknown, this characteristic cannot be incorporated in the full key.

1. 1.Tibia 2–3 times as long as tergite. Epipharynx with 18–21 sensilla … Choleva Latreille, 1796
2. –Tibia less than 2 times as long as tergite. Epipharynx with 12 sensilla ………………… ……………………… Nargus Thomson, 1867

Habitat

Myrmecophile, in nests of Atta structor (Latreille, 1798) (= Messor structor (Latreille, 1798)) (Xambeu 1892).

Distribution

Central and western Europe.

Diagnosis

Tibia 2–3 times as long as tergite. Epipharynx with 18–21 sensilla.

Key to the species of larval instar I of Choleva

1. 1.Dd2 on tergites very close to end of carina and Dd1*. Appendage on antennomere III longer than wide. 2 extra dorsal setae on antennomere II (Figs 41, 42). On urogomphomere I, gap between proximal group of 5 setae and distal group of 3 setae more than half the length of urogomphomere I (Figs 45, 46) (Choleva agilis-group) ……………………………… 2
2. –Dd2 on tergites lower. Appendage on antennomere III as long as wide, or shorter. More than 2 extra setae on antennomere II (Fig. 43). Gap on urogomphomere I less than half of the length of urogomphomere I (Figs 44, 47) …………………………………………… 3
3. 2.Smaller, stouter species. Posterior tibia 0.44 ± 0.02 mm ………… C. (C.) agilis (Illiger, 1798)
4. –Larger, more slender species. Posterior tibia 0.58 ± 0.02 mm … C. (C.) lederiana Reitter, 1902
5. 3.Antennae polytrichic, antennomeres I and II with multiple additional setae. Lateral end of the anterior carina on tergites with single seta …………………………………………… 4
6. –Antennomere I with 1 seta, antennomere II with 2 extra setae ventrally and 3–4 extra setae dorsally. Lateral end of the anterior carina on tergites with group of 3 minute setae ……………… C. (C.) oblonga Latreille, 1807
7. 4.Maxillary palpomere II with 3 setae ………… …………… C. (C.) angustata (Fabricius, 1781)
8. –Maxillary palpomere II with 4–5 setae ……………… C. (C.) fagniezi Jeannel, 1922

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Antennae of instar I. Red rectangles indicate the diagnostic setae, blue rectangles indicate the SA on AIII. – 40, Choleva fagniezi Jeannel, 1922; 41, Choleva agilis (Illiger, 1798); 42, Choleva lederiana Reitter, 1902; 43, Choleva oblonga Latreille, 1807.

Citation: Tijdschrift voor Entomologie 167, 1-3 (2024) ; 10.1163/22119434-bja10033

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Urogomphomere I of instar I. Red lines indicate the gap between the most proximal 5 setae and the most distal 3 setae. – 44, Choleva fagniezi Jeannel, 1922; 45, Choleva agilis (Illiger, 1798); 46, Choleva lederiana Reitter, 1902; 47, Choleva oblonga Latreille, 1807.

Citation: Tijdschrift voor Entomologie 167, 1-3 (2024) ; 10.1163/22119434-bja10033

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Key to the species of larval instars II and III of Choleva

1. 1.On urogomphomere I, gap between proximal group of 5 setae and distal group of 3 setae more than half of the length of urogomphomere I. Maxillary palpomere II with 4 setae in L2 and L3 …………… Choleva agilis-group 2
2. –Gap on urogomphomere I less than half of the length of urogomphomere I. Maxillary palpomere II not always with exactly 4 setaeand L3 ………………………………………… 3
3. 2.Apex of mandible with 2–3 rounded teethand L3…………………C. (C.) agilis (Illiger, 1798)
4. –Apex of mandible with 4 pointed teeth (Fig. 51)and L3……C. (C.) lederiana Reitter, 1902
5. 3.Apex of mandible with 4 pointed teeth (Figs 48, 50)and L3…………………………………4
6. –Apex of mandible with 2 rounded teeth (Fig. 49)and L3……………C. (Cholevopsis) spadicea
7. 4.Dorsal-proximal tooth on mandible apex with an entirely smooth or slightly serrated bottom edge (Fig. 48). Retinaculum pointed (L2) or rounded (L3, Fig. 48). Lacinia with 6 or 7 teethand L3…………………………………5
8. –Dorsal-proximal tooth on mandible apex with a strongly serrated bottom edge (Fig. 50). Retinaculum pointed (Fig. 50). Lacinia with 5 teeth …………C. (C.) oblonga Latreille, 1807
9. 5.Maxillary palpomere II with 4 (L2) or 6 (L3) setae. Mandible with 5 setae and L3 ……………… C.) angustata (Fabricius, 1781)
10. –Maxillary palpomere II with 7 (L2 & 3) setae. Mandible with 7 setae (Fig. 48)and L3 ……………… C. (C.) fagniezi Jeannel, 1922

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Mandibles of instar III. – 48, Choleva fagniezi Jeannel, 1922; 49, Choleva spadicea (Sturm, 1839); 50, Choleva oblonga Latreille, 1807; 51, Choleva lederiana Reitter, 1902.

Citation: Tijdschrift voor Entomologie 167, 1-3 (2024) ; 10.1163/22119434-bja10033

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Diagnosis

Instar I: Epipharynx with 18–21 sensilla. Mala with row of 5–6 setae. Maxillary palpomere II with 2 setae. Antennomere I without setae, antennomere II with 2 additional setae dorsally (Fig. 41). Appendage on antennomere III long (Fig. 41). Tergites with P1, P2, P5, P5’, L, Lb, Dd2; Da1 and Dd1*; and 5 additional setae between P1, P5, and the anterior carina. Position of Dd2 high, near Dd1*. Urogomphomere I with 8 setae, 5 campaniform sensilla (Fig. 45). Large gap between the 5 most proximal setae and the 3 most distal setae (Fig. 45). Posterior tibia 0.44 ± 0.02 mm (Pinto 2015).

Instar II & III: Mandible with 2–3 smooth apical teeth. Maxillary palpomere II with 4 setae. Tergites between the posterior row and the anterior carina with 10–20 setae. Urogomphomere I with 8 setae, 5 campaniform sensilla, large gap.

Distribution

Central and western Europe except Spain, up to the Netherlands in the north; Turkey.

Diagnosis

Instar I: Epipharynx with 20–21 sensilla. Mala with row of 7 setae. Maxillary palpomere II with 3 setae. Antennae polytrichic, antennomeres I and II with many more setae. Appendage on antennomere III short. Tergites with P1, P2, P5, P5’, L, Lb, Dd2; Da1 and Dd1*; and 5 additional setae between P1, P5, and the anterior carina. Position of Dd2 regular, between L and Dd1*. Urogomphomere I with 8 setae, 5 campaniform sensilla. No gap between the 5 most proximal setae and the 3 most distal setae.

Instar II & III: Mandible with 5 setae, apex with 4 pointed apical teeth. On right mandible, most proximal tooth with a smooth bottom edge. Maxillary palpomere with 5 (L2) or 6 (L3) setae. Tergites between the posterior row and the anterior carina with 28–30 setae. Urogomphomere I with 8 setae, 5 campaniform sensilla, no gap.

Distribution

Central and western Europe, up to Greece.

Diagnosis

Instar I: Epipharynx with 20–21 sensilla. Mala with row of 7–8 setae. Maxillary palpomere II with 4–5 setae. Antennae polytrichic, antennomeres I and II with many more setae (Fig. 40). Appendage on antennomere III short (Fig. 40). Tergites with P1, P2, P5, P5’, L, Lb, Dd2; Da1 and Dd1*; and 4–5 additional setae between P1, P5, and the anterior carina. Position of Dd2 regular, between L and Dd1*. Urogomphomere I with 8 setae, 5 campaniform sensilla (Fig. 44). Small gap between the 5 most proximal setae and the 3 most distal setae (Fig. 44).

Instar II & III: Mandible with 7 setae, apex with 4 pointed apical teeth (Fig. 48). On right mandible, most proximal tooth with a weakly serrated bottom edge (Fig. 48). Maxillary palpomere with 7 setae. Tergites between the posterior row and the anterior carina with 20–30 setae. Urogomphomere I with 8 setae, 5 campaniform sensilla, no gap.

Distribution

Southwestern France; Spain.

Diagnosis

Instar I: Epipharynx with 20–21 sensilla. Mala with row of 5–6 setae. Maxillary palpomere II with 2 setae. Antennomere I without setae, antennomere II with 2 additional setae dorsally (Fig. 42). Appendage on antennomere III long (Fig. 42). Tergites with P1, P2, P5, P5’, L, Lb, Dd2; Da1 and Dd1*; and 5 additional setae between P1, P5, and the anterior carina. Position of Dd2 high, near Dd1*. Urogomphomere I with 8 setae, 5 campaniform sensilla (Fig. 46). Large gap between the 5 most proximal setae and the 3 most distal setae (Fig. 46). Posterior tibia 0.58 ± 0.02 mm (Pinto 2015).

Instar II & III: Mandible with 4–6 setae, apex with 4 pointed apical teeth (Fig. 51). On right mandible, most proximal tooth with a smooth bottom edge (Fig. 51). Maxillary palpomere with 4 setae. Tergites between the posterior row and the anterior carina with 10–20 setae. Urogomphomere I with 8 setae, 5 campaniform sensilla, large gap.

Distribution

Endemic to Bad Segeberg, Germany.

Diagnosis

Instar I: Epipharynx with 18 sensilla. Mala with row of 6 setae. Maxillary palpomere II with 2 setae. Antennomere I with 1 seta, antennomere with 3–4 additional setae dorsally and 2 additional setae ventrally (Fig. 43). Appendage on antennomere III short (Fig. 43). Tergites with P1, P2, P5, P5’, L, Lb, Dd2; Da1; and 5 (5–6) additional setae between P1, P5, and the anterior carina. Near the lateral ends of the anterior carina, three minute setae instead of just Dd1*. Position of Dd2 regular, between L and lateral end of the anterior carina. Urogomphomere I with 8 setae, 5 campaniform sensilla (Fig. 47). Small gap between the 5 most proximal setae and the 3 most distal setae (Fig. 47).

Instar II & III: Mandible with 5 setae, apex with 4 pointed apical teeth (Fig. 50). On right mandible, most proximal tooth with a serrated bottom edge (Fig. 50). Maxillary palpomere with 2 setae. Urogomphomere I with 8 setae, 5 campaniform sensilla, small gap.

Distribution

Central and western Europe; Middle East.

Diagnosis

Instar I & II: Morphology unknown.

Instar III: Apical teeth of mandible rounded (Fig. 49). Maxillary palpomere with 2 setae. Posterior row of tergites with 9 setae. Tergites between the posterior row and the anterior carina with 20–25 setae. Urogomphomere I with 8 setae, 5 campaniform sensilla, small gap.

Distribution

Central and western Europe, up to the Netherlands in the north, up to Romania in the east.

Diagnosis

Tibia at most 2 times as long as tergite. Epipharynx with 12 sensilla. Maxillary palpomere II with 2 setae.

Instar I: Antennomere I without setae.

Diagnosis

Instar I: Antennomere II without additional setae.

Distribution

Central and western Europe.

Diagnosis

Instar II: Mandible with 4 setae. Mandible with 4 pointed apical teeth. On right mandible, most proximal tooth with a smooth bottom edge (Fig. 52). Maxillary palpomere with 2 setae.

Distribution

Eastern and central North America.

Diagnosis

Apex of mandible long. Prostheca tooth-like, with 1, 2, or 3 teeth, sometimes only present on the left mandible, or completely absent. Retinaculum often only on the right mandible, often completely absent; rarely on both mandibles. Antennomere III in L1 often with a pigmented band, faint in some species and always absent in L2. Antennomere III also with third additional setiform sensillum, replacing the campaniform sensillum in Catopina and the shorter SA in Cholevina. Urogomphi often strongly reduced, even absent, but if present, URI always has 8 setae and 5 campaniform sensilla.

Diagnosis

Extensively described by Franciscolo (Franciscolo 1948, 1953), who also provides a key to four of the species in the genus. The genus can be distinguished from many other Leptodirini by an additional pair of dorsal setae on the labrum (Franciscolo 1953).

Diagnosis

Larval morphology not known.

Distribution

Western Europe.

Key to the genera of Ptomaphagini larvae

1. 1.Both mandibles with a prostheca. URI at least as long as wide. (Ptomaphagina) … 2
2. –Right mandible without prostheca, retinaculum long. URI very short, wider than long; urogomphomere II much longer (Ptomaphaginina) …………………… Proptomaphaginus
3. 2.Mandible with pointed apical teeth ………………… Ptomaphagus Hellwig, 1795
4. –Mandible with rounded apical teeth …………………… Adelopsis Portevin, 1907

Diagnosis

Extensively described by Gnaspini (1993b).

Distribution

Brazil.

Diagnosis

Epipharynx with 8 c.s. and 2 pairs of sensilla. Prementum without c.s. Apices of mandibles symmetrical, bidentate. Prostheca frayed, bristle-like. Mala with a row of 5–6 setae. Maxillary palpomere II with 1–2 setae, 3 in P. hirtus. Urogomphomere I with 6 setae, 5 campaniform sensilla.

Instar I: Tergites with chaetotaxy like Catopina, with P1, P2, P5, P5’, L, Lb, Dd2; Da1 and Dd1*; and Da2–Dc2. Position of Dd2 high, near Dd1*.

Instar II & III: Tergites with 4 large and 4 secondary setae in the posterior row, and 5–10 secondary setae between the posterior row and anterior carina.

Key to the species of larval instar I of Ptomaphagus

1. 1.Maxillary palpomere II with 1 seta ……………………………………… P. (P.) thebeatles Schilthuizen, Latella & Njunjić, 2021
2. –Maxillary palpomere II with 2 setae ……… 2
3. 2.Maxilla with 5 setae … P. (P.) medius (Rey, 1889)
4. –Maxilla with 6 setae ………………………………………… P. (P.) subvillosus (Goeze, 1777)

Key to the species of larval instar II and III of Ptomaphagus

1. 1.Mandibles with retinaculum. Maxillary palpomere II with 2 setae (subgenus Ptomaphagus) …………………………………………… 2
2. –Mandibles without retinaculum. Maxillary palpomere II with 3+ setae ……………………… ………… P. (Adelops) hirtus (Tellkampf, 1844)
3. 2.Mala and lacinia not elongated (cf. 31). Maxillary palpomere III nearly twice as long as maxillary palpomere II ……………………… 3
4. –Mala elongated, teeth of lacinia far apart (Fig. 55). Maxillary palpomere II just longer than maxillary palpomere III ………………………………P. (P.) varicornis (Rosenhauer, 1847)
5. 3.No ocelli. Antennomere I with 2 setae …… 4
6. –One pair of crescent-shaped ocelli. Antennomere I with 2 (L2) or 3 (L3) setae ………………P. (P.) subvillosus (Goeze, 1777)
7. 4.Front edge of dorsal-proximal tooth on mandible apex smooth (Fig. 53) …………………… …………………… P. (P.) medius (Rey, 1889)
8. –Front edge of dorsal-proximal tooth on mandible apex with a bump (c.f. Fig 54) … P. (P.) thebeatles Schilthuizen, Latella & Njunjić, 2021

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Mandibles of instar III. – 53, Ptomaphagus medius (Rey, 1889); 54, Ptomaphagus varicornis (Rosenhauer, 1847).

Citation: Tijdschrift voor Entomologie 167, 1-3 (2024) ; 10.1163/22119434-bja10033

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Right maxilla of Ptomaphagus (Ptomaphagus) varicornis (Rosenhauer, 1847).

Citation: Tijdschrift voor Entomologie 167, 1-3 (2024) ; 10.1163/22119434-bja10033

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Diagnosis

No description of instar I. Instar II and III have mandibles without retinacula and maxillary palpomeres II with 3 or more setae.

Habitat

Caves.

Distribution

Midwestern United States.

Diagnosis

Maxillary palpomere II with 2 seta.

Instar I: Maxilla with 5 setae.

Instar II & III: Maxilla with 6 setae. Mandibles with retinaculum, on right mandible the retinaculum is bifurcated, rounded (Fig. 53). Front edge of dorsal-proximal tooth on mandible apex smooth (Fig. 53).

Distribution

Northern and western Europe, recently expanding to Central Europe; Canada (Schilthuizen et al. 2021).

Distribution

Central, southern, and eastern Europe (Schilthuizen et al. 2021).

Diagnosis

Maxilla with 6 setae. No ocelli.

Instar I: Maxillary palpomere II with 1 seta.

Instar II & III: Maxillary palpomere II with 2 seta. Mandibles with retinaculum, on right mandible the retinaculum is bifurcated, rounded. Front edge of dorsal-proximal tooth on mandible apex with a bump.

Distribution

Western and southern Europe, reaching southern Russia in the east, and recently expanding northwards (Schilthuizen et al. 2021).

Diagnosis

Maxilla with 6 setae. Maxillary palpomere II with 2 seta. One pair of crescent-shaped ocelli.

Instar III: Antennomere I with 3 setae.

Distribution

Central and western Europe.

Diagnosis

Morphology of instar I is unknown.

Instar II & III: Mala elongated, teeth of lacinia far apart (Fig. 55). Maxillary palpomere II is just longer than maxillary palpomere III (Fig. 55). Mandibles with retinaculum, on right mandible the retinaculum is bifurcated, pointed (Fig. 54).

Distribution

Europe, up to Denmark in the north, up to Russia in the east.

Diagnosis

Right mandible without prostheca, retinaculum long. Urogomphomere I very short, wider than long.

Distribution

Cuba.

Accuracy

More specimens should be collected of the species that were included, especially from different regions, to confirm the characteristics presented in this study. Firstly, even though care was taken to only implement characteristics without overlap, chaetotaxy was found to be variable in several areas of the larva. This could mean more extreme outliers exist that would be identified incorrectly using this key. Secondly, the rounded mandible shape of Choleva spadicea could be caused by wear, though no similar wear was found in other species. Thirdly, a specific set of specimens available to the authors are possibly misidentified. Seven of the 14 specimens labelled C. morio that were collected in Leiden, The Netherlands in the 1980s have both the brown spot characteristic for S. watsoni, and the pair of campaniform sensilla on the prementum uncharacteristic for C. morio. Of the remaining seven larval specimens, none of which have the brown spot, the prementum is visible in three and in all of these the pair of campaniform sensilla is missing as expected. This strongly indicates the former seven species are misidentified or mislabelled, and the latter seven are labelled correctly. A larger set of larval specimens with confirmed identifications could indicate whether this is indeed the case, or whether those characteristics (brown spot, c.s. on prementum) are variable.

Key to the tribes. Kilian and Mądra (2015) questions the validity of the key to genera for larvae of Cholevinae by Zwick (1978), used here as a base for the key to tribe, stating: “characters leading to Sciodrepoides are, from evidence produced during the present study, incorrect.” However, based on our reading of their publication, the key correctly identifies Sciodrepoides: in instar I, the inner edge of the mandible is concave (Kilian & Mądra 2015, Fig. 23), URI is drawn as approx. 97 µm (Kilian & Mądra 2015, Fig. 54) and abdominal tergite X as approx. 112 µm (Kilian & Mądra 2015, Fig. 50), URII not more than three times as long as URI (Kilian & Mądra 2015, Fig. 54), and the prostheca is described as a “simple lobe”; in instar III, the inner edge of the mandible is straight (Kilian & Mądra 2015, Figs 24, 25), URI is drawn as approx. 159 µm (Kilian & Mądra 2015, Fig. 55) and abdominal tergite X as approx. 178 µm (Kilian & Mądra 2015, Fig. 52), URII not more than three times as long as URI (Kilian & Mądra 2015, Fig. 55), and the mean length of L2 is listed as 2.79 mm. The discrepancy possibly arises from counting the anal membrane as part of abdominal segment X or not.

Chaetotaxy of Sciodrepoides watsoni. Sciodrepoides watsoni had recently been described with modern terminology in great detail (Kilian & Mądra 2015), meaning the species was suitable for a comparison with the material of S. watsoni and other species in Catopina available to the author. This comparison revealed a number of significant differences in the chaetotaxy of instar I, where setae found in the material of S. watsoni and other Catopina species were not included in the descriptions by Kilian and Mądra.

Head. Both S. watsoni and S. fumatus show an additional frayed seta on the lateral granulated areas behind the antennae, as well as a line of 3–7 setae extending from the larger one to the ventral surface, all seemingly homologous to the L’ setae in the later instars. An additional seta can be found on the ventral surface, between Vl1 and L. None of these setae seem to be present in the description by Kilian and Mądra (2015).

Antennae. The antennae are mostly similar apart from the campaniform sensilla on AI. In instar I, all Cholevini including both Sciodrepoides species, have two campaniform sensilla in the basal half of the segment, whereas the figure in their description shows four sensilla along the distal edge of the segment (Kilian & Mądra 2015, Fig. 21). The figure for instar III does show these sensilla (Kilian & Mądra 2015, Fig. 22).

Abdominal segments. In instar I, most Catopina have an additional seta on both halves of each tergite between Dd1* and P5, not present in their description (Kilian & Mądra 2015, Fig. 42), and tentatively labelled Dd2 in these descriptions.

Urogomphi. Kilian and Mądra (2015) include for instar I of Sciodrepoides watsoni a figure with seven setae and four campaniform sensilla, the difference consisting of the proximal ventral seta and one of the proximal sensilla (Kilian & Mądra 2015, Fig. 54). The text only mentions six setae, and it is unclear which seta from the figure is not included in that count. Furthermore, the figure shows two dorsal distal setae, as opposed to one dorsal and one ventral seta, which does not match the present findings.

It is unclear to the authors what these differences signify, as Kilian and Mądra confirmed the identity of their specimens using both molecular and morphological methods. The presence of these setae and sensilla across Catopina species may suggest that the specimens examined by Kilian and Mądra display strong local variation. However, this interpopulation variation would be larger than many interspecific differences.

Identifying characteristics

The resulting key primarily uses mandible shape and the relative length of urogomphomere I for the distinction of tribes, and size as well as the chaetoxy of the mandible, maxilla, antenna, tergite, and urogomphi for distinction of species within genera. In future studies, chaetotaxy of the head capsule, thorax, and legs could be explored for further identifying characteristics. Microsculpture, glands, and reservoirs were also found to be potentially useful sources of identification characteristics for other subfamilies in Leiodidae (Kilian 2012). Further, the width of the labrum could be used as a measure of overall size instead of tibia length, as it is not dependent on the relevant length of appendages.

Application

The keys are currently not usable for the full identification to species of unknown specimens as the key is incomplete even for the Dutch fauna. To improve the taxonomic and geographical coverage of the key, specimens of additional species are required. However, these keys do provide a scaffold for the further development of a key to the species of (Northwestern) Europe.

The morphological characteristics used in the keys may also be used to further investigate the phylogeny of the group. Even though in general existing taxonomic divisions were used to structure the keys, this was not feasible for Catops sensu lato, i.e., Apocatops, Catops, Fissocatops, Sciodrepoides, with the characteristics used in this study. This concurs with a phylogenetic reconstruction of Catopina which shows Catops as a paraphyletic genus (Schilthuizen et al. 2016). Conversely, some taxonomic groups were found to be strongly delineated by larval morphology as well as phylogeny, such as the Catops fuscus-group (Schilthuizen et al. 2016).

The same morphological characteristics can also be related to ecological traits of the larvae. For example, the less concave mandibles found in later instars of Catops larvae could be suitable for clipping the feather rami and pieces of hair found in the guts of some of the larvae.