Caucasodesmus tauricus, Sergei I., Golovatch, 2011
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publication ID |
https://dx.doi.org/10.3897/zookeys.93.1159 |
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https://treatment.plazi.org/id/F054D185-E0F2-58E0-72C2-A6E18080054E |
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scientific name |
Caucasodesmus tauricus |
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sp. n. |
Caucasodesmus tauricus ZBK sp. n. Figs 18
Type material:
Holotype ♂, Ukraine, Crimea, Mt Villya-Burun, Cave Villyaburunskaya, pitfall traps, 12.05.2008-12.10.2010, leg. A. Koval. - Paratype: 1 ♀, same locality, 19.07.2004-17.07.2006, leg. A. Koval.
Diagnosis:
Easily distinguished from Caucasodesmus inexpectatus Golovatch, 1985, the type, and only other, known species of this genus, by the abundantly setose metaterga and more elaborate gonopods.
Description:
Length of both sexes ca 8 mm, width of midbody pro- and metazona 0.8 and 1.5 mm, respectively. Coloration in alcohol from uniformly pallid to light yellowish.
Body with 20 segments. Tegument mainly dull, at most slightly shining, texture very delicately alveolate. Head densely pilose throughout; epicranial suture distinct but thin; isthmus between antennae ca 1.5 times broader than length of antennomere 1, still broader than diameter of antennal socket. Antennae rather short, evidently clavate due to a considerably enlarged antennomere 6, slightly overreaching segment 2 dorsally; antennomeres 2, 3 and 6 longest, subequal in length (Figs 1, 2); only antennomere 6 with a large, compact, roundish, distodorsal group of bacilliform sensilla.
In width, collum <segment 2 = 3 <head = 4 <5=16 (♂) or head = collum = segment 2 = 4 <5=16 (♀), thereafter body gradually tapering towards telson. Paraterga moderately developed, starting from collum, subhorizontal to slightly declivous, set high but always lying slightly below a faintly convex dorsum, devoid of shoulders frontally (Figs 1-3). Caudal corner of postcollum paraterga invariably spiniform, pointed, starting from segment 4 extending increasingly further than rear tergal margin. Lateral edge of paraterga with neither marginal groove nor thickening, with 5-6 clear setigerous indentations. Pore formula normal, ozopores evident, round, located laterally in front of caudalmost incision. Collum and following metaterga beset with numerous medium-sized setae set on minute knobs, polygonal bosses missing (Figs 1-3). Stricture between pro- and metazona wide, shallow and smooth. Limbus very thin, microdenticulate. Pleurosternal carinae absent (Fig. 2). Epiproct short, conical, directed caudoventrally; preapical papillae small (Fig. 4). Hypoproct subtrapeziform, setiferous papillae at caudal corners evident, rather well separated.
Sterna without modifications, poorly setose. Epigynal ridge very low. Legs rather short (Figs 2, 5), ca 1.2-1.3 (♂) or 0.9-1.0 (♀) times as long as midbody height; ♀ legs slightly slenderer; ♂ legs with clearly enlarged prefemora and femora; tarsi especially long and slender, claw long, ca 1/4 length of tarsus; sphaerotrichomes missing (Fig. 5).
Gonopod aperture large, transversely oblong-oval, taking up nearly all of ventral part of metazonite 7. Gonopods (Figs 6-8) with large, globose, medially fused coxae carrying rather numerous setae laterally, but no trace of a cannula. Telopodite subfalcate, distally of a rather short prefemoral (= setose) portion split into two branches: exomere (ex) largest and longest, more simple, whereas endomere (en) shorter, more complex in shape; an evident, tooth-like, mesal process (d) at base between both ex and en; no trace of a seminal groove.
Remarks.
This species is an unquestioned relict troglobite and, based on its zoogeographical traits, might well represent the first palaeoendemic in the diplopod fauna of the Crimea.
Only one species of Caucasodesmus has hitherto been known: Caucasodesmus inexpectatus from Cave Nyvjin Lagat (= Nyvdzhinlagat, = Tagardonskaya) in North Ossetia, central Caucasus Major ( Golovatch 1984/85). The second congener, Caucasodesmus tauricus sp. n., shares with the type species such remarkable, clearly generic-level apomorphies as the absence of bacilliform sensilla on antennomeres 5 and 7, of a cannula on the gonocoxite, and of a seminal groove on a biramous gononod telopodite. Apparently, both latter characters are functionally correlated to each other, differing from the loss of a cannula alone which is observed in the families Dalodesmidae and Rhachodesmidae . The differences lie in Caucasodesmus inexpectatus showing a far more moniliform body, only three transverse rows of setae on the collum and following metaterga, and less strongly elaborate gonopod telopodites.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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