Troglocaris (Xiphocaridinella) kumistavi, Marin, 2017

Marin, Ivan, 2017, Troglocaris (Xiphocaridinella) kumistavi sp. nov., a new species of stygobiotic atyid shrimp (Crustacea: Decapoda: Atyidae) from Kumistavi Cave, Imereti, Western Georgia, Caucasus, Zootaxa 4311 (4), pp. 576-588 : 578-586

publication ID	https://doi.org/ 10.5281/zenodo.848469
DOI	https://doi.org/10.5281/zenodo.6000781
persistent identifier	https://treatment.plazi.org/id/260087ED-FFE0-1E7A-AFD7-FCCDFDE84B4D
treatment provided by	Plazi
scientific name	Troglocaris (Xiphocaridinella) kumistavi
status	sp. nov.

Treatment

Troglocaris (Xiphocaridinella) kumistavi View in CoL sp. nov.

(Figs. 2 a, b, 3–7)

Material examined. Holotype: non-ovigerous female (pcl. 7.0 mm, tl. 22.0 mm), ZMMU Ma 5834, MF287654 View Materials , Caucasus, Western Georgia, Imereti region, Tskaltubo-Kumistavi, 42°22'35.8"N 42°36'03.2"E, Kumistavi Cave, in subterranean stream, about 100 meters above the sea level, coll. A. Sokolova & D. Palatov, 15 Sept. 2016 GoogleMaps . 4 nonovigerous females, 2 males (LEMMI), same locality and date as holotype; 5 ovigerous females, 2 males GoogleMaps , same locality as holotype, February 2017 GoogleMaps .

Description. Medium-sized shrimp with swollen, smooth, subcylindrical body. Carapace swollen, smooth, with small dorsal carina in frontal part. Rostrum (Figs. 2 a, b, 3, 4) relatively long, slender, curved upward, reaching the midlength of second antennular segment, sometimes almost reaching its distal margin ( Fig. 3 View FIGURE 3 e, f), sharply pointed distally, with tip turned upward, broad proximally, with developed lateral lamina; rostrum armature and length greatly vary (Figs. 2 a, b, 3, 4), usually rostrum armed with relatively long slender dorsal spines (up to 11) and 1 or 2 distal ventral teeth. Rostral formula of the species — 0–4+0–11/0–2. The rostrum of some specimens (Fig. 2 a) seems to be the longest among all known species of the Caucasian representatives of the genus Troglocaris (Xiphocaridinella) (Birštein, 1939; Juzbaš’jan, 1940; Marin & Sokolova, 2014).

Abdominal somites smooth, unarmed; tergites non-carinate, without dorsal lobes, not posteriorly produced; pleura of pleomeres I–IV posteroventrally and ventrally rounded; pleomere V small, with feebly developed pleura; distal and distoventral margins of pleomere VI sharply produced posterodorsally. Telson ( Fig. 5 View FIGURE 5 d, e) relatively slender, smooth, about 3.5 times as long as wide proximally, expanded distally, with 2 pairs of slender dorsal spines, each about 0.08 of telson length, inserted at about 0.35 and 0.6 telson length respectively; distal margin convex, with 5–7 pairs of distal spines, including a pair of short lateral spines, a pair of long intermediate spines and 3–5 pairs of slender medial dorso-marginal spines.

Eyes (Figs. 2, 3) small, partly reduced, swollen, subcylindrical, mostly covered by carapace; cornea rounded, reduced and feebly marked, without pigment; eyestalk stout, swollen, cylindrical, about as long as wide.

Antennula ( Fig. 5 View FIGURE 5 b) with stout unarmed articles, basal peduncular segment robust, about twice longer than proximal width, without ventromedial tooth, distolateral angle with broadly produced sharp projection ( Fig. 5 View FIGURE 5 c); stylocerite stout, sharpening distally, overreaching the midlength of basal segment; second and third segments stout, unarmed; second segment about 1.5–2 times as long as wide and about 1.5–2 times as long as distal segment; distal segment about as long as wide.

Antenna with basicerite stout, about 1.5 times as wide as long, with distolateral margin unarmed; carpocerite robust, about 1.5 times as long as wide, not reaching midlength of scaphocerite; scaphocerite well developed, broad, with small but well marked distolateral tooth, lamella bluntly rounded distally.

Mouth parts characteristic for the genus. Maxilliped III ( Fig. 6 View FIGURE 6 l) with slender segments; epipodite stout, bluntly rounded; arthrobranch reduced, but present; exopodite slender, reaching the distal margin of antepenultimate segment; antepenultimate segment slender, about 8 times as long as wide; penultimate segment about 7–8 times as long as wide, with straight lateral margins; ultimate (distal) segment slender, equal to penultimate segment, about 7 times as long as wide, tapering distally, with tufts of short simple stick-like setae along ventral and lateral margins, with several tufts of long setae dorsally.

Pereiopods I equal in size and similar in shape, and similar in males ( Fig. 6 View FIGURE 6 a) and females ( Fig. 6 View FIGURE 6 e), with smooth unarmed segments; coxa with well-developed slender epipodite and tuft of setobranchs; basis about as long as wide, with well-developed exopodite overreaching carpo-meral articulation; ischium about 3.5–4 times longer than wide, with straight margins; merus slender, about 3 times as long as wide, equal to ischium, with straight margins; carpus relatively stout in males and slightly more slender in females, significantly widening distally, slightly longer than merus, about as 1.5 times as long as maximal width; palm relatively stout, about as long as wide, subcylindrical in cross-section, smooth; fingers relatively slender, subcylindrical, smooth, with blunt distal margins, about 4 times as long as proximal width, armed with a row of stout strong plumose setae.

Pereiopods II ( Fig. 6 View FIGURE 6 b, f) equal in size and similar in shape, similar to pereiopod I and similar in males and females, with relatively stouter basal smooth unarmed segments; coxa with well-developed slender epipodite and tuft of setobranchs; basis about as long as wide, with well-developed exopodite overreaching carpo-meral articulation; ischium about 3 times as long as wide, with straight margins, unarmed; merus slender, about 3 times as long as wide, usually equal to ischium or lightly longer, with straight margins; carpus slender, about 8 times as long as wide, slightly widening distally, longer than merus; palm relatively stout, similar to palm of pereiopod I, about as long as wide, subcylindrical in cross-section, smooth; fingers relatively slender, subcylindrical, smooth tapering distally, about 4.5–5 times as long as proximal width, with simple and straight cutting edges, with broad blunt distal margin, armed with a row of stout strong plumose setae.

Pereiopod III in females ( Fig. 6 View FIGURE 6 g) with articles; coxa rectangular, about as long as wide, with tuft of setobranchs, with small epipodite; basis about as long as wide, with well-marked exopodite almost reaching the midlength of merus; ischium about 1.5 times as long as wide, with well-marked distoventral spine; merus about 6 times as long as wide, with straight margins, with 3 well marked spines along ventral margin; carpus relatively slender, about 6 times as long as wide, slightly widening distally, about twice shorter than merus and slightly longer than half of the length of propodus, with bluntly projecting distodorsal margin overlapping carpo-propodal articulation and small subdistal spine; propodus about 10 times as long as wide, with straight margins, armed with 7–8 spines along proximal half of ventral margin ( Fig. 6 View FIGURE 6 h); dactylus ( Fig. 6 View FIGURE 6 h) about 3 times longer than wide, biunguiculate, ventral margin armed with 6–7 small spines, main unguis smooth, curved and sharp; accessory unguis triangular, sharp, slightly larger than ventral teeth, about twice shorter than main unguis. Pereiopod IV in females ( Fig. 6 View FIGURE 6 i) generally similar to pereiopod III; merus armed with 3 spines, carpus armed with single spine; exopodite smaller than in pereiopod III. Pereiopod V in females ( Fig. 6 View FIGURE 6 j) generally similar to pereiopods III and IV, but without armature on basal segments and exopodite on basis; segments covered with simple setae dorsally and ventrally; propodus about 7–8 times as long as wide, with straight margins, armed with 8–10 long spines along ventral margin and pair of long slender spines at distoventral angle; dactylus ( Fig. 6 View FIGURE 6 k) with ventral margin armed with a dense “brush” consisting of small simple sharp setae; without accessory unguis, main unguis curved, triangular, sharp distally.

Morphological differences between males and females lead in the structure of distal part of propodi and dactyli of pereiopods III and IV ( Figs. 6 View FIGURE 6 c, d, g, h). Pereiopod III in males ( Fig. 6 View FIGURE 6 c) with relatively slender segments; coxa rectangular, about as long as wide, with tuft of setobranchs, with epipodite; basis about as long as wide, with wellmarked exopodite almost reaching the midlength of merus; ischium about 1.5 times as long as wide, with wellmarked distoventral spine; merus about 7 times as long as wide, with straight margins, with 3 well marked spines along ventral margin; carpus relatively slender, about 6 times as long as wide, slightly widening distally, about twice shorter than merus and 1.5 times shorter than propodus, with bluntly projecting distodorsal margin slightly overlapping carpo-propodal articulation, with a single subdistal spine; propodus about 8 times as long as wide, with straight margins, distal third of propodus widening and armed with a series of small spines along its ventral margin; dactylus ( Fig. 4 View FIGURE 4 d) about 4 times as long as wide, with single unguis, ventral margin armed with small relatively stout sharp teeth, main unguis smooth, curved and sharp.

Pleopod I in males ( Fig. 5 View FIGURE 5 g) with endopod bearing well marked appendix interna ( Fig. 5 View FIGURE 5 h). Pleopod II in males ( Fig. 5 View FIGURE 5 g) with well-developed appendix interna and appendix masculina ( Fig. 5 View FIGURE 5 j); appendix masculina covered with numerous small sharp stout simple spines ( Fig. 5 View FIGURE 5 j). Pleopods I and II in females normal, characteristic for the genus without specific differentiating features.

Uropods relatively stout, slightly exceeding telson; lateral margin of uropodal exopodite straight, with sharp triangular distolateral angle and large curved distolateral spine; dieresis simple, without spines.

Coloration. Body and appendages of shrimps are transparent whitish; cornea of eyes albescent; internal organs (gonads and hepatopancreas) are whitish or yellowish; numerous small transparent fat granules can be seen through carapace ( Fig. 7 View FIGURE 7 ).

Body size. The largest collected female has tbl. 8.0 mm, pcl. 24.0 mm; the largest collected male has tbl. 6.0 mm, pcl. 20.0 mm.

Distribution. The species is known from the type locality, underground stream and lakes inside Kumistavi (Prometheus) Cave (42°22'35.8"N 42°36'03.2"E), Tskaltubo-Kumistavi, Imereti region, Western Georgia, Caucasus.

GenBank accession numbers. MF287654 View Materials , MF287652 View Materials , MF287653 View Materials .

Etymology. The species is named after the Kumistavi Cave where it was found. Kumistavi Cave, also known as the Cave of Prometheus, was discovered in Imereti region in 1984, and now is considered as the biggest karst cave in Georgia. Kumistavi owes a famous Caucasian myth about Caucasian ethnic hero Amirani for the sonorous naming of the "Cave of Prometheus". The legend says that “ Amirani, like Prometheus, angered the gods and was punished. Days and nights eagle tormented him eating his liver; however, in contrast to the Greek giant, cruel gods chained Amirani not to the rock, but somewhere inside a huge cave (presumably, in Kumistavi)”.

Ecological remarks. The specimens of Troglocaris (Xiphocaridinella) kumistavi sp. nov. were collected both in subterranean stream and small lakes inside Kumistavi Cave. Several ovigerous females with 10–15 large eggs as well as relatively numerous post-juveniles were found in February in tiny lake inside the cave, representing the first described locality in Georgia where Caucasian Troglocaris shrimps were found breeding (“breeding pool”). Previously, only non-ovigerous females and males of Troglocaris shrimps were found in Caucasian underground lakes and cave streams; probably they were washed out there from their underground “breeding pools” by flood water (Marin & Sokolova, 2012).