European Journal of Taxonomy 363: 1–20 ISSN 2118-9773 https://doi.org/10.5852/ejt.2017.363 www.europeanjournaloftaxonomy.eu 2017 · Schneider C. & Deharveng L. This work is licensed under a Creative Commons Attribution 3.0 License. R e s e a r c h a r t i c l e urn:lsid:zoobank.org:pub:5720CF48-37A8-4814-93F3-192493488435 1 First record of the genus Spinaethorax Papáč & Palacios-Vargas, 2016 (Collembola, Neelipleona, Neelidae) in Asia, with a new species from a Vietnamese cave Clément SCHNEIDER 1,* & Louis DEHARVENG 2 1 Mécanismes Adaptatifs & Evolution, MECADEV - UMR 7179 - CNRS, MNHN, Dpt Systematics & Evolution, Muséum national d'Histoire naturelle, CP50 Entomology, 45 rue Buffon, 75005 Paris, France. 2 Institut de Systématique, Evolution, Biodiversité, ISYEB – UMR 7205 – CNRS, MNHN, UPMC, EPHE, Muséum national d’Histoire naturelle, Sorbonne Universités, 57 rue Cuvier, CP 50, 75005 Paris, France. *Corresponding author: clement.schneider@mnhn.fr 2 Email: dehar.louis@wanadoo.fr 1 urn:lsid:zoobank.org:author:C0BEC337-0235-4E4B-8EFB-134B3EED1B90 2 urn:lsid:zoobank.org:author:D8F5C679-C30C-442C-8621-D3B8EDB17EF7 Abstract. A new species of the genus Spinaethorax Papáč & Palacios-Vargas, 2016, recently erected for  two cave species of Mexico, is described from a Vietnamese cave. It differs from the Mexican species most noticeably by the dorsal chaetotaxy of the head (number and morphology of chaetae), the shape of S-chaetae on the third antennomere, the dorsal chaetotaxy of the abdomen and the chaetotaxy of the dens. The pattern of special τ-chaetae is described for the first time in the genus. The affinities between  Spinaethorax and the other genera of Neelipleona are discussed. Spinaethorax is probably closely related to Neelus Folsom, 1896. A table of the differential characters is provided for the three known species of Spinaethorax. Spinaethorax appears to be restricted to caves, but its presence in Vietnam indicates that this genus has a much larger distribution than previously recognized. Keywords. Taxonomy, chaetotaxy, Vietnam, cave fauna, springtail. Schneider C. & Deharveng L. 2017. First record of the genus Spinaethorax Papáč & Palacios-Vargas, 2016  (Collembola, Neelipleona, Neelidae) in Asia, with a new species from a Vietnamese cave. European Journal of Taxonomy 363: 1–20. https://doi.org/10.582/ejt.2017.363 Introduction Neelipleona is one of the four orders of Collembola (Massoud 1971, 1976) and contains a single family, Neelidae. The group remained little studied since the discovery of its first representative, Neelus murinus Folsom, 1896. A recent series of morphological and/or molecular contributions has greatly improved the systematics of Neelipleona (Kováč & Papáč 2010; Schneider et al. 2011, 2016; Papáč &  Kováč 2013; Schneider & D’Haese 2013; Papáč et al. 2016), especially the genera Neelus Folsom, 1896 and Megalothorax Willem, 1900. Schneider (2017) redescribed the generotypes of Neelus, Neelides Caroli, 1912 and Acanthoneelidus Bretfeld & Griegel, 2006 and gave an account of the morphological https://doi.org/10.5852/ejt.2017.363 http://www.europeanjournaloftaxonomy.eu/index.php/ejt/index https://creativecommons.org/licenses/by/3.0/ http://zoobank.org/urn:lsid:zoobank.org:pub:5720CF48-37A8-4814-93F3-192493488435 mailto:clement.schneider@mnhn.fr mailto:dehar.louis@wanadoo.fr http://zoobank.org/urn:lsid:zoobank.org:author:C0BEC337-0235-4E4B-8EFB-134B3EED1B90 http://zoobank.org/urn:lsid:zoobank.org:author:D8F5C679-C30C-442C-8621-D3B8EDB17EF7 https://doi.org/10.582/ejt.2017.363 European Journal of Taxonomy 363: 1–20 (2017) 2 knowledge on the entire Neelipleona. This latter work, however, did not include first-hand observations of  Zelandothorax Delamare Deboutteville & Massoud, 1963 or of the recently erected genus Spinaethorax Papáč & Palacios-Vargas, 2016. Spinaethorax was created by Papáč & Palacios-Vargas (2016) to accommodate two cave species of Mexico, Megalothorax spinotricosus Palacios-Vargas & Sánchez, 1999 and M. tonoius Palacios-Vargas & Sánchez, 1999. Papáč & Palacios-Vargas (2016) defined  Spinaethorax with the following character set: presence of sensory fields (shared with all genera, except Neelides), sword-like macrochaeta on oral fold (unique), 6 + 6 chaetae on basomedian fields of labium (unique), fusion of antennomeres III/ IV (shared with Megalothorax and Zelandothorax), 3 + 3 teeth on tenaculum (shared with Neelus and some Megalothorax), 1 + 1 neosminthuroid chaetae on sternum of abdomen IV (shared with Neelus and Acanthoneelidus), two chaetae on proximal part of dens (shared with adults of most Neelus species), absence of chaeta E3 on distal part of dens (in adult; shared with Megalothorax, Zelandothorax and Acanthoneelidus) and three chaetae close to the abdominal sensory field (unique). Collecting carried out during a long-term biodiversity assessment of the Hon Chong karst in South Vietnam led to the discovery of a new species, Spinaethorax adamantis sp. nov. The present paper includes a thorough morphological description of Spinaethorax adamantis sp. nov. and a review of the definition of the genus Spinaethorax. The pattern of τ-chaetae (Schneider et al. 2016) is for the first time  described in a species of Spinaethorax. Additional information is given on the morphological affinities  of Spinaethorax with the other genera of Neelipleona. Homologies between the genera are suggested for certain morphological characters. A table of the differential characters between the three known species of Spinaethorax is provided. Material and methods Environmental context The new species was collected in a small cave of a karstic hill of the Hon Chong karst system in southern Vietnam, close to the border with Cambodia. This karst, an exceptionally rich hot-spot of endemism, is currently under critical threat due to limestone exploitation (Deharveng et al. 2009). The cave Hang Kim Cuong itself is small, 67 m long (Laumanns 2011), developed at the foot of a rocky hill close to the seaside. The species was obtained by Berlese extraction of thin debris spread irregularly on the floor,  but was not found in the small patches of guano present in the cave. This dark, moderately humid cave hosts a remarkable fauna when visited in 2006, including numerous Collembola, some of which are apparently undescribed: Acrocyrtus sp., Ceratophysella sp., Folsomides sp. near F. americanus Denis, 1931, Lepidonella lecongkieti Deharveng & Bedos, 1995, Megalothorax laevis Denis, 1948, a blind Rambutsinella sp. and several new species of Pronura and Willemia. Sampling and observations The specimens were extracted from the sample with a simple Berlese funnel and stored in 96 % ethanol. They were cleared in lactic acid and mounted on microscope slides in Marc André II medium. They were examined with a Leica DMLB differential phase contrast microscope with magnifications of ×250  to ×1000. Drawings were made with a drawing tube and vectorized with Inkscape. Characters of S. spinotricosus and S. tonoius are based on the descriptions of Palacios-Vargas & Sánchez (1999) and Papáč & Palacios-Vargas (2016). Measurements were performed with a graduated slide. Values given  in µm were measured on a single specimen chosen among the biggest, ratios and proportions are average measures from several relevant specimens. SCHNEIDER C. & DEHARVENG L., First record of Spinaethorax in Asia 3 Terminology and conventions The terminology follows Schneider & D’Haese (2013), Schneider et al. (2016) and Schneider (2017). Chaetal categories used in the description are defined in Schneider (2017). When referenced, Neelus murinus is always sensu Massoud & Vannier (1967). The genus names Neelus and Neelides will not be abbreviated for their respective species in order to avoid ambiguity. Abbreviations and symbols in text Antenna Ant. I–IV = antennomere I to IV S1–S5 = S-chaetae of Ant. III Or = Ant. IV organite S, Sx, Sy = S-chaetae of Ant. IV Head and trunk Abd. I–VI = abdominal segment I to VI av = chaetae of anal valves s1, s2, s3, s3’ = s-chaetae on trunk sf1–6 =  sensory fields 1 to 6 and associated wax rod secretory element Th. I–III = thoracic segment I to III τ  =  τ-chaetae wrc1–wrc8 = free wax rod secretory elements 1 to 8 Claw la, lp, Bp = auxiliary lamellae of unguis Institutional abbreviations HCMU = Ho Chi Minh City National University, Department of Biology, University of Natural Sciences, Ho Chi Minh City, Vietnam MNHN = Muséum national d’Histoire naturelle, Paris, France Results Class Collembola Lubbock, 1873 Order Neelipleona Massoud, 1971 Family Neelidae Folsom, 1896 Genus Spinaethorax Papáč & Palacios-Vargas, 2016 Figs 1–8, 9A, D; Table 1 Revised diagnosis Eyes and post-antennal organ absent. Secondary granulation made of fine grains; dermastra missing;  integumentary channels absent. Anterior process of labrum absent or very weak. Ant. III and IV fused; S-chaeta S1 short and wide; S-chaeta S5 present; two apical sensory rod-like chaetae (a, sa). Basomedian fields of labium with 4 + 4 chaetae; basolateral fields of labium with 3 + 3 chaetae. Oral fold with  enlarged lateral chaeta. Sensory fields well-developed with swollen inner chaetae; sf6 with three guard chaetae. Trunk with 4 + 4 s-chaetae (s1, s2, s3, s3’). Abd. IV sternum with 1 + 1 neosminthuroid chaetae. Distal articular process of manubrium with convex tip. Dens without median articular process. Unguis with basal narrowing; with well developed lamella Bp; lamella la missing on unguis II. Tenaculum with 3 + 3 teeth. European Journal of Taxonomy 363: 1–20 (2017) 4 Keys or tables for determination of the genera of Neelidae are available in Papáč & Palacios-Vargas  (2016) and Schneider (2017). Spinaethorax adamantis sp. nov. urn:lsid:zoobank.org:act:B0F131AB-279A-4890-A33B-ED70D437828D Figs 1–8, 9A, D; Table 1 Diagnosis Postero-dorsal area of head with 12 + 12 chaetae including 5 + 5 lanceolate chaetae. Antero-dorsal area of head with two unpaired chaetae. Ant. III with 14 chaetae; S-chaetae S2, S3, S4 long and tubular. Dorsal area of Th. II with 4 + 4 thickened or lanceolate chaetae. Abd. I–V terga without spine-like microchaetae. Abd. VI tergum with thickened chaetae. Subcoxa 2 III and coxa III with thickened chaetae. Dens proximal part with one strong chaeta. Differential diagnosis Spinaethorax adamantis sp. nov. differs from S. spinotricosus and S. tonoius in several characters, summarized in Table 1. Most notably, S. adamantis sp. nov. has only one proximal chaeta on dens (instead of two in the other species), long and tubular S-chaetae S2, S3 on Ant. III (vs short in the other species) and a long and tubular S-chaetae S4 (vs short and globular in the other species). S. adamantis sp. nov. and S. tonoius differ most strikingly from S. spinotricosus by the absence of the numerous spine- like microchaetae (reduced number of ordinary chaetae instead). Fig. 1. Spinaethorax adamantis sp. nov., habitus, with enlargement of the protuberance bearing wax rod secretory element of sf6. http://zoobank.org/urn:lsid:zoobank.org:act:B0F131AB-279A-4890-A33B-ED70D437828D SCHNEIDER C. & DEHARVENG L., First record of Spinaethorax in Asia 5 Etymology The name is derived from the Latin adamas (diamond) and is inspired by the local name for the cave Hang Kim Cuong, “Diamond Cave”, in which the new species was collected. The name emphasizes that one of its richnesses lies in the biodiversity instead of actual diamonds. Material examined Holotype VIETNAM: ♂, on slide (MNHN-EA040281), Kien Giang Province, Kien Luong, Hon Chong karst, Nui Hon Chong hill (also called Nui Chua Hang), Hang Kim Cuong (Diamond Cave), 28 Nov. 2006, X=104.639784 E, Y=10.137582 N, elevation about 15 m, extracted with Berlese funnel from soil in the dark zone of the cave, L. Deharveng and A. Bedos leg. (sample Vn06-088) (MNHN). Paratypes VIETNAM: 3 ♀♀, 1 ♂, 1 specimen of unknown sex on 3 slides, same data as the holotype, three paratypes deposited in the collection of the MNHN (France), two paratypes in the collection of the HCMU (Vietnam). Description Size. Length from labrum to anus of largest specimen ~550 µm. Pigmentation. Whitish in alcohol. general ShaPe and body Segmentation (Fig. 1). Orthognathous. Antennae directed laterally with a slight curve toward the anterior direction, slender. Ant. III and IV fused. Total length of antenna ~ 148 µm; max width (Ant. III) ~ 18 µm; ratio width : length ~ 0.12; relation of length of Ant. I : Ant. II : Ant. III : Ant. IV 0.15 : 0.5 : 1 : 1. Point of insertion of head on Th. I aligned with antero-posterior axis of the head. Diameter of Th. I slightly reduced without steep curve between Th. I–head and Th. I–II. Th. I in one part, neck missing. Th. I–head articulary folds not observed. Terga from Th. II to Abd. V fused. Posterior granule T of the dorso-median line missing, replaced by a small unpaired patch devoid of secondary granules (T, Fig. 4A). Wax rod secretory elements of sf3 (dorsal area of Th. II) and of sf6 (dorsal area of abdomen) standing on strong, protruding processes (Fig. 1). Precoxal area of Th. II and III without clear anterior lobe. Each coxa long and bent. On leg I and II length of coxa > tibiotarsus > femur > trochanter. On leg III length of coxa > tibiotarsus ~ femur > trochanter. Abd. VI sternum clearly separated posteriorly from Abd. VI tergum by large anal aperture, separated anteriorly from Abd. V sternum by a steep curve, Abd. VI sternum distinct laterally from the great abdomen terga by the absence of secondary granulation. Abd. IV sternum enlarged, creating a large ventro-posterior side bearing the furca. Abd. I–III sterna reduced with tenaculum close to ventral tube. Manubrium/dens articular processes: manubrium with weak process bearing hardened peg with convex tip that connects to concave tip of strong, projecting process of dens (Fig. 6C). Dens proximal part wider than the distal part with a steep curve between the two. No suture line or articular process between proximal and distal part of dens (Fig. 6D). Relation of length of manubrium : dens proximal part : dens distal part : mucro ~ 0.90 : 0.32 : 1 : 0.82. integument. With a simple secondary granulation made of fine granules. Secondary granulation present  on posterior part of Th. II to Abd. V terga (Fig. 4A), absent on head, antennae, Abd. VI tergum, furca, legs, thoracic and abdominal sterna. Dermastra missing. Integumentary channels missing. Chaetae. Seven morphological variations of chaetae on head and trunk: (i) ordinary chaetae; (ii) s-chaetae, short and swollen chaetae (s1–s3, s3’) found on trunk; (iii) τ-chaetae, long and flexible chaetae shaped as  trichobothria with basal ring implanted in a small depression of the integument and weakly contrasted in light microscopy, found on trunk (~30–35 µm, Fig. 4B); (iv) wax rod secretory crypts associated with European Journal of Taxonomy 363: 1–20 (2017) 6 Ta bl e 1. D if fe re nt ia l c ha ra ct er s fo r th e th re e sp ec ie s of th e ge nu s Sp in ae th or ax . S . t on oi us a ft er P al ac io s- V ar ga s & S an ch ez ( 19 99 ) an d Pa pá č  &  P al ac io s- V ar ga s  (2 01 6) , S . s pi no tr ic os us a ft er  P ap áč  &  P al ac io s- V ar ga s  (2 01 6) . S. a da m an tis s p. n ov . S. to no iu s S. s pi no tr ic os us H ea d N um be r o f c ha et ae : p os te ro - 12 +1 2 (5 +5 la nc eo la te ) / 3 +3 12 +1 2 (1 +1 la nc eo la te ) / 2 +2 10 +1 0 (4 +4 la nc eo la te ) / 2 +2 do rs al a re a / p os te ro -l at er al a re a N um be r o f c ha et ae : a nt er o- do rs al 10 +1 0 + 2 un pa ir ed / 5+ 5 ? / ? 9+ 9 + 1 un pa ir ed / 2+ 2 ar ea / an te ro -l at er al a re a L an ce ol at e ch ae ta e re la tiv e si ze IL 1 > IL 2 ~ IL 4 ~ IL 5 > IL 3 N /A IL 1 > IL 2 > IL 4 > IL 5 A nt en na A nt . I II 14 c ha et ae (6 b el ow S 4) , 12 c ha et ae (5 b el ow S 4) , 15 c ha et ae (7 b el ow S 4) , S2 , S 3, S 4 lo ng a nd tu bu la r S2 a nd S 3 sh or t, S4 g lo bu la r S2 a nd S 3 sh or t, S4 g lo bu la r A nt . I V 14 c ha et ae (i nc lu di ng 5 w ith s lig ht 11 c ha et ae , 9 S -c ha et a S 13 c ha et ae , 1 3 S- ch ae ta e S   m od ifi ca tio n) , 1 2  S- ch ae ta e  S Tr un k T h. II d or sa l a re a— nu m be r o f 4+ 4 ?( 3+ 3– 4+ 4) 6+ 6 th ic ke ne d or la nc eo la te c ha et ae A bd . I –V te rg a ch ae to ta xy ra ng in g fr om 2 7+ 27 to 3 1+ 32 c ha et ae ?( >2 5 + 25 c ha et ae ) ?( 3 + 3 ch ae ta e) + >8 0 sp in e- lik e m ic ro ch ae ta e A bd . V I t er gu m — ch ae ta l m or ph ol og y th ic ke ne d ? th in Le gs L eg I (s ub co xa 1 –t ib io ta rs us ) 1, 1 , 1 , 4 , 9 , 1 3 1, 1 , ? , 3 , 8 , 1 2 1, 1 , 1 , 4 , 8 , 1 3 L eg II (s ub co xa 1 –t ib io ta rs us ) 1, 1 , 1 , 3 , 8 , 1 4 1, 1 , ? , 2 , 7 , 1 2 1, 1 , 1 , 3 , 8 , 1 4 L eg II I ( su bc ox a 1– tib io ta rs us ) 2, 1 , 2 , 4 , 8 , 1 3 1, 1 , ? , 3 , 7 , 8 3, 1 , 2 , 3 , 8 , 1 3 Su bc ox a 2 II I a nd c ox a II I th ic ke ne d ? or di na ry ch ae ta e m or ph ol og y U ng ui s II I la a bs en t ?l a ab se nt la p re se nt F ur ca Pr ox im al  p ar t o f d en s,   1  2  (a ft er  P ap áč  &   2 nu m be r o f c ha et ae (a du lt) Pa la ci os -V ar ga s 20 16 ) SCHNEIDER C. & DEHARVENG L., First record of Spinaethorax in Asia 7 Fig. 2. Spinaethorax adamantis sp. nov. A–B. Chaetotaxy of the head. A. Dorsal side. B. Ventral side, anterior part. C. Labrum dorsal side. D–F. Labium. D. Focus on papillate chaetae of the palp. E. Focus on chaetae in proximal field. F. focus on papilla H. G–H. Maxilla, different views. I. Left mandible. J–K. Maxilla outer lobe. J. Lateral side. K. Ventral side. Abbreviations: blf = basolateral field of labium;  bmf = basomedian field of labium; mol = maxilla outer lobe; of = oral fold. Labial palp lettering after Fjellberg (1999). European Journal of Taxonomy 363: 1–20 (2017) 8 a sensory field; (v) free wax rod secretory crypts (wrc1–8); (vi) inner swollen chaetae of sensory fields;  (vii) neosminthuroid chaetae. Ordinary chaetae size ranging from microchaetae [1–6 µm], mesochaetae [7–15 µm] to macrochaetae [16 µm–42 µm]. Ordinary chaetae morphology ranging from simple to lanceolate; including spectacular lanceolate macrochaetae on head and thorax (Figs 2A, 4A). SenSory fieldS and wax rodS. Six pairs of sensory fields (sf1–6) on head and trunk, each field associated  with a wax rod secretory crypt (Figs 2A, 4A). On head: sf1 preantennal without special inner chaeta (Fig. 2A); sf2 postantennal without special inner chaeta (Fig. 2A). On trunk: sf3 dorsally on Th. II with three short candlelight-shaped inner chaetae (Fig. 4A); sf4 in precoxal area of Th. II with two short candlelight-shaped inner chaetae (Fig. 4A); sf5 in precoxal area of Th. III and sf6 dorsally on posterior part of abdomen, each with a short candlelight-shaped inner chaeta (Fig. 4A). sf6 well developed (Fig. 4A). Eight pairs of free wax rod secretory crypts (seven in Th. III tergum area, eight in abdominal terga area) (Fig. 4A). Edges of sf5 and wrc5 separate, wrc8 in antero-ventral position and close to sf6 (Figs 4A, 9D). Tertiary wax rod secretory elements apparently missing. labrum. Labrum without clearly differentiated anterior process, a-row of chaetae very close to labral ridge (Fig. 2C). a-row consisting of two pairs of smooth, slightly thickened and strongly curved mesochaetae (a1, a2). m- and p-rows of chaetae each with five mesochaetae (Fig. 2C). Labral ridge without apical hairs or spines (Fig. 2C). labium.  Basomedian  fields  with  4  +  4  mesochaetae  (Fig. 2B,  D–E).  Basolateral  fields  with  3  +  3  mesochaetae (lateral chaetae on weak tubercles) and with small antero-lateral integumentary processes (Fig. 2B, D–E). Proximal field with four mesochaetae (Fig. 2E). Palp with six papillate chaetae and six guard hairs as (H, h1, h2), (A), (B), (b2, b4), (C), (D, d2), (E, e) (lettering sensu Fjellberg 1999). Hypostomal papilla (H) with a strong, apically enlarged chaeta, other papillae with acuminate, straight or slightly curved chaetae (Fig. 2D, F). other mouthPartS. Oral fold with two chaetae and a microspine, ventral chaeta enlarged and strongly curved near the base, lateral chaeta of ordinary morphology (Fig. 2A–B, J). Maxilla outer lobe with sub-basal mesochaeta and apical papilla bearing a mesochaeta (Fig. 2J–K), apical papilla without annex hair (Fig. 2J–K), sublobal plate with strong hair (Fig. 2J–K). Left and right mandibles each with four apical, rounded teeth (Fig. 2I). Maxilla with at least four cilliated lamellae, capitulum with two hooked teeth (Fig. 2G–H). head Chaetotaxy. Postero-dorsal area with 12 + 12 chaetae: 5 + 5 macrochaetae, 6 + 6 mesochaetae in f.p–pa.a-rows, 1 + 1 mesochaetae on the border of sf2 (Figs 2A, 7A). Postero-lateral area with 3 + 3 mesochaetae (Figs 2A, 7A). Antero-dorsal area with 10 + 10 mesochaetae and two unpaired mesochaetae (Figs 2A, 7A). Antero-lateral area with 1 + 1 macrochaetae and 4 + 4 mesochaetae (Figs 2A, 7A). Ventral area with 3 + 3 post-labial mesochaetae (Figs 2B, 7B). antennal Chaetotaxy. Ant. I with three dorsal chaetae (Fig. 3A). Ant. II with six chaetae in two whorls, one in basal whorl, five in apical whorl (Fig. 3A–B). Ant. III with 14 chaetae in 4 rough whorls distributed as 1, 2, 4, 7 (Fig. 3A–B), of varied morphology, ranging from thin ordinary chaetae to “S-chaetae S-like”; five S-chaetae (S1–S5). S1 as a plump, stalked chaeta, possibly with four folds (Fig. 3A, D), S2–S4 long and tubular with blunt apex, S5 short with pointed apex (Fig. 3A–B). Ant. IV with 14 chaetae, 14 S-chaetae (12 S, Sx, Sy), one organite (Or) and two apical and subapical sensory rods (a, sa) (Fig. 3A–C). Five chaetae slightly departing from the ordinary morphology in a large and contrasted basal ring, a subtly more tubular aspect (vs conical aspect) and outward curving (vs inward curving) (Fig. 3A–B). S-chaetae S scarcely differentiated from ordinary macrochaetae, with apex finely  rounded. Sy thick and tubular with round apex, Sx as long as Sy but slender with round apex (Fig. 3A, C). SCHNEIDER C. & DEHARVENG L., First record of Spinaethorax in Asia 9 Organite apparently bifid with two thin arms apically converging, one perceptibly larger than the other  (Fig. 3A, C). Ornamentation of S-chaetae not seen with light microscopy. Fig. 3. Spinaethorax adamantis sp. nov. A–D. Chaetotaxy of the antenna. A. Dorsal side. B. Ventral side. C. Focus on S-chaeta Sx and Organite Or with enlargement of the latter. D. S-chaeta S1, different aspects. Asterisks indicate modified chaetae. Chaetae implanted on the other side represented with gray stroke.  European Journal of Taxonomy 363: 1–20 (2017) 10 th. ii–abd. V terga Chaetotaxy. Th. II–Abd. V terga with a minimum of 52 + 52 chaetae, 12 + 12 τ-chaetae, 4 + 4 s-chaetae (s1, s2, s3, s3’) and 8 + 8 wrc (Figs 4A, 7C). Dorso-lateral areas of Th. II with 5 + 5 macrochaetae, 4 + 4 mesochaetae and 2 + 2 τ-chaetae (Figs 4A, 7C), lengths of the 5 macro- and 4 mesochaetae 13–40 µm: a4 (13 µm)