Paracortina kyrang, Nguyen & Stoev & Nguyen & Vu, 2023

Nguyen, Anh D., Stoev, Pavel, Nguyen, Lien T. P. & Vu, Tam T., 2023, A new species of Paracortina from a Vietnamese cave, with remarkable secondary sexual characters in males (Callipodida, Paracortinidae), ZooKeys 1149, pp. 181-195 : 181

publication ID	https://dx.doi.org/10.3897/zookeys.1149.99651
publication LSID	lsid:zoobank.org:pub:52FBD435-5320-4F08-8EBB-F18230DC9B62
persistent identifier	https://treatment.plazi.org/id/22146F0D-BFA6-4F91-84B5-CEB60238183D
taxon LSID	lsid:zoobank.org:act:22146F0D-BFA6-4F91-84B5-CEB60238183D
treatment provided by	ZooKeys by Pensoft
scientific name	Paracortina kyrang
status	sp. nov.

Treatment

Paracortina kyrang sp. nov.

Figs 1 View Figure 1 , 2 View Figure 2 , 3 View Figure 3 , 4 View Figure 4 , 5 View Figure 5 , 6 View Figure 6 , 7 View Figure 7

Material examined.

Holotype. 1 male (IEBR-Myr 921) Cao Bang Province , Quang Hoa District , Quoc Toan commune, Ky Rang Cave, 2.xi.2021, leg. Anh D. Nguyen.

Paratypes. 1 female, 1 juvenile (IEBR-Myr 932), 1 female (IEBR-Myr 935) same locality, but 17.iii.2022, leg. Anh D. Nguyen & D.D. Nguyen.

Non-types. 1 male, 1 male juvenile, 1 female juvenile (IEBR-Myr 954), same locality, but 16.x.2018, leg. Alexandre Faille.

Diagnosis.

The new species is well distinguished from all congeners by the strongly modified head in males bearing a unique apically bent projection. Body composed of 68-74 pleurotergites +telson, eyes reduced, composed of 19 or 20 ommatidia in two or three rows. Gonocoxa with an anterior long spiniform process (a), as long as ca 80% of telopodite stem, and a rather slender, much shorter, cephalad process (b). Process a with a cephalad lobe distally, process b about 1/3 the length of telopodite. Telopodite with two long, clavate prefemoroidal processes (cp), densely covered with long macrosetae apically. Telopodite long, slender, apically twisted laterad, with a distal, reverse, short spine. Distal part of telopodite rather sinuous, narrowed at the base, then smoothly widened at its top, to narrow sharply finally at the solenomere (sl) and parasolenomere (ps).

The new species can be keyed out into the first branch in Liu et al.'s (2015) key for identification of the species of Paracortina , with the clustering species having a pair of prefemoroidal clavate processes (cp) on the gonopods: P. thallina , P. stimula , P. leptoclada , P. voluta , P. serrata , P. viriosa , and P. carinata (all from southern China).

Etymology.

The species epithet " kyrang " is a noun in apposition for the type locality, Ky Rang Cave.

Description.

Male holotype: Length about 42 mm, width and height of midbody PT 2.3 mm and 2.2 mm, respectively; 68 PT+ telson.

Colour: living specimens greenish white (Fig. 1C, D View Figure 1 ). Ethanol preserved specimens: generally white-yellowish; posterior part of metazonites with a brown posterior margin; head, pleurotergites, antennae and telson white-yellowish; legs yellow-brownish.

Head (Figs 2A-C View Figure 2 , 3A View Figure 3 ) highly modified; frons considerably elongated in large projection (lp), which is curved at its end; forehead and vertex concave.

Antennae (Figs 2A View Figure 2 , 3A View Figure 3 , 4B View Figure 4 ) extremely long, extending beyond the posterior edge of PT 9 when folded backwards; ratio antenna/body length about 1/7; all antennomeres white; length of antennomeres: 1: 0.21 mm, 2: 1.27 mm, 3: 1.26 mm, 4: 1.26 mm, 5: 1.21 mm, 6: 0.67 mm, 7: 0.23 mm; tip of antennomere 7 with four cones protruding well beyond the edge. Eyes (Fig. 2B, C View Figure 2 ) black, well delineated, composed of 19 ommatidia in three horizontal rows (9+3+7). Tömösváry’s organ about three times larger than the adjacent ommatidium, placed between the eye and the base of antenna (Fig. 2B View Figure 2 ).

Width of PT: 6>7>>8-14>4>3>2>1. PT slightly broader than high; height of 10thPT: 2.19 mm, width 2.32 mm.

Collum (Fig. 2B, C View Figure 2 ) much narrower than head; pleurotergites 6 and 7 in males strongly enlarged (Figs 2D View Figure 2 , 3A View Figure 3 ). Crests on collum (Fig. 2C View Figure 2 ) moderately expressed mostly in the posterior part of the segment. Complete crests series appearing from PT2 onwards. Above ozopores, midbody PT with 3+3 primary crests and with 3+3 secondary short crests between primary crests (Figs 2D View Figure 2 , 3B View Figure 3 ); 3rd primary crest strongly enlarged, other primary crests flattened, almost equally broad along the metazonal length; only secondary crests shorter and slightly narrowed posteriorly. Ozopores lying on primary crest 3, visible from sixth to last but two PT (Figs 2D View Figure 2 , 3B View Figure 3 ).

Below ozopores, midbody PT with 2+2 primary crests and 2+2 shorter and thinner secondary crests between primary crests, and 8-10 lower crests down to ventral pleurotergal edge (Fig. 3A View Figure 3 ).

Midbody pleurotergal setae 5+5, located at caudal edges of primary crests (Figs 2D View Figure 2 , 3A View Figure 3 ); setal pattern as in below (Chaetotaxy). Axial line rather distinct.

Epiproct (ep) (Fig. 3B-D View Figure 3 ) simple, with 7+7 anterior and 4+4 posterior setiferous knobs in transverse rows. Hypoproct (hp) (Fig. 4D View Figure 4 ) tripartite, medial sclerite largest, subtrapeziform, bearing two paramedian macrosetae; each lateral sclerite with a single macroseta born on a large tubercle. Paraprocts (pp) (= anal valves) (Fig. 4D View Figure 4 ) smooth, each divided into a small upper and large lower sclerites, both with a pair of macrosetae. Spinnerets long and slender, ending with a long seta each. All setae on telson brown, contrasting with the yellowish background.

Male leg-pairs 1 and 2 much shorter, with strong setae on ventral side of femorite and tibia, leg-pair 3 slightly shorter than following legs. Tarsi 1-3 1-segmented, and from tarsus 4 to ultimate pair 2-segmented; tarsal pads large until leg 26, then gradually thinner and eventually absent on subsequent legs. All legs ending with a rather slender, long, curved claw. Coxal sacs present from legs 3-26 (PT 16). Only coxae and tibia finely micropapillate ventrally (Fig. 4B View Figure 4 ).

Coxa 2 with a small anterior process and a posterior gonopore, the latter placed on a small cone (Fig. 4C View Figure 4 ). Coxa 6 normal, without processes or modifications. Coxa 7 (Fig. 6A, B View Figure 6 ) with a short tubercle (st), and a very strong, rounded anterior process (rap). Coxae of the remaining legs normal.

Chaetotaxy:

	Anterior setae	Posterior setae
Collum	4+4	2+2
PT2	5+5	broken
PT3	5+5	broken
PT4	broken	5+5
PT5	broken	5+5
PT6-penultimate PT		5+5 (rarely 6+5)

Gonopods (Figs 6C, D View Figure 6 , 7 View Figure 7 ) yellow-brownish, some parts dark brown to black (seminal groove, solenomere, basal part of coxal process a). Gonopods protruding well beyond the gonocoel, stems of telopodites long, thin, subparallel, and diverging, pointing posteriad (Fig. 6C, D View Figure 6 ). Coxa with an anterior long spiniform process (a), and a rather slender, much shorter, posterior process (b) (Fig. 6C View Figure 6 ). Process a as long as ca 80% of telopodite stem, with a lobe distally while process b about 1/3 the length of telopodite. Telopodite (te) with two long, clavate prefemoroidal processes (cp), densely covered with long macrosetae apically. Telopodite long, slender, apically twisted laterad, with a distomesal, reverse, short spine (sp) (Figs 6C View Figure 6 , 7A, B View Figure 7 ). Distal part of telopodite rather sinuous, narrowed at the base, then smoothly widened at its top, to narrow sharply finally at the solenomere (sl) and parasolenomere (ps) (Fig. 7D View Figure 7 ). The seminal groove (sg) terminating in the solenomere (Fig. 7D View Figure 7 ).

Females. Head unmodified (Fig. 5A-C View Figure 5 ). Length about 54.7 mm. The 10thPT ca 2.62 mm wide and 2.36 mm high; 68-74 PT + telson. Second leg-pair unmodified. Leg-pairs 1-3 with tarsal brushes. Cyphopods small, densely setose, bilobed (Figs 4D View Figure 4 , 5A, D View Figure 5 ). Coxae 7 normal, without processes.

DNA barcode.

The new species has a close genetic identity with Tetracion jonesi Hoffman, 1956 ( Abacionidae ) from 77.74% to 78.25%.

Cave habitat.

Ky Rang Cave is located in close proximity to Thang Hen Lake in Cao Bang Province, northern Vietnam, at the altitude of 1,000 m a.s.l. The cave entrance is wide, but the only passage is blocked by an artificial door made by the local residents. Because of it, the semi-light part of the cave is missing, and, on entry, the cave is immediately dark (Fig. 1A View Figure 1 ). The cave is high (15-20 m), wide (15-20 m), and long (700-1,000 m). The floor is mainly wet with clay and there are some small pools (Fig. 1B View Figure 1 ). Several other millipede species were found in the cave, for example, Hylomus srisonchaii Golovatch, 2019 and Hyleoglomeris alba Kuroda, Nguyen & Eguchi, 2022 ( Golovatch 2019; Kuroda et al. 2022). The new species was found at a distance of 500 m from the entrance.