Nepalella grandis, Golovatch & Geoffroy & Mauriès, 2006

Golovatch, Sergei I., Geoffroy, Jean-Jacques & Mauriès, Jean-Paul, 2006, Four new Chordeumatida (Diplopoda) from caves in China, Zoosystema 28 (1), pp. 75-92 : 80-83

Nepalella grandis n. sp.

( Figs 1 D-G; 4)

TYPE MATERIAL. — Holotype: China, Yunnan Prov., Zheng Xiong County, Cave Bai Yin Dong, Nos. 523 & 524, 18.VIII.1999, leg. J. & B. Lips, ♂ ( MNHN DB42 ). Paratypes: same locality, 1 ♂ ( MNHN DB42 ) ; 1 ♀ ( MNHN DB42 ) ; 1 ♀ ( MNHN DB42 ) ; 6 juvs ( MNHN DB42 ) .

ETYMOLOGY. — To emphasize the particularly large size.

DIAGNOSIS. — Differs from congeners by the particularly large size, as well as certain details of leg and gonopod structure. The unusually strong colpocoxites, surmounted by a pseudosegmented head-like structure, also make N. grandis n. sp. easily distinguishable.

DESCRIPTION

Length c. 40 (♂) to 42 mm (♀), maximum width 2.8 (♂) to 2.9-3.0 mm (♀). Coloration entirely pallid.

Head width = segment 6 = 20 >> collum> segment 2> 3> 5 <7; after segment 20 or 21, body very gradually tapering toward telson.

Body with 30 segments. Head densely setose, clypeolabral region slightly convex. Eye patches triangular, each composed of 10 (♀) or 15 (♂) rather convex ocelli. Antennae extremely long and slender ( Figs 1D ; 4A ), reaching beyond body segment 8 dorsally; antennomere 7 with a peculiar flattened seta dorsally in distal third. Gnathochilarium without promentum.

Collum usual, obcordate in shape, with rudimentary paraterga ( Fig. 1A ). Tegument smooth, shining, translucid, only prozona distinctly and densely striolate transversely. Metatergal setation 3 + 3, typical, macrochaetae medium-sized, rather thick but pointed, positioned on minute knobs; stricture between pro- and metazona very shallow, inconspicuous ( Fig. 1 D-F).

Paraterga small dorsolateral swellings/shoulders, not set off by peritremata, rather regularly rounded in dorsal view, only more abruptly so after caudal corner ( Fig. 1 D-F).

CIX (15) = 0.46; MIX (15) = 2.08; MA (15) ≈ 165°; PIX impossible to evaluate as paraterga too poorly developed. Axial suture distinct, usual; segment 7 only very slightly broader than adjacent ones, conspicuous due to a clearly visible and frontally projecting anterior lobe of pleurite, latter without ventral apophyses. Limbus barely visible, microdentate, traceable only near pleurites ventrolaterally.

Legs very long and slender, slightly longer in males than in females, c. 1.8 times as long as midbody height. Legs 1 and 2 slightly reduced as usual, tarsi with usual ventral brushes, but without papillae; male coxa 2 perforated by gonopore orifice. All tarsi slightly bulging immediately at base, male prefemora microgranulate ventrally ( Fig. 4E ). Male legs 3-7 somewhat incrassate, pairs 3 and 4 especially so, each conspicuously papillate over caudal face of distoventral third ( Fig. 4B ). Male legs 10 and 11 with coxal glands; prefemur 10 conspicuously enlarged at base ( Fig. 4C ); prefemur 11 with a strong, microgranulate, parabasal process ventrally ( Fig. 4D ). Claws invariably long, sabre-shaped, simple.

Anterior gonopods (leg-pair 8) as usual very strongly reduced, sternum with a median protuberance and two lateral lobules, coxites spike-like ( Fig. 4F ).

Posterior gonopods (leg-pair 9) hypertophied ( Fig. 4G, H ), with two ear-shaped folds at base on anterior face of colpocoxites and two large flagella beset with simple pilosity. Bases of coxite with two small, roundish bulges beset with minute plumose setae on caudal face. Colpocoxites especially prominent, higher than telopodites, distal one-third gently curved and directed distocaudally, delimited at base by a transverse sulcus on front face, with a relatively small, recurved, spoon-shaped process at base of caudal face, and an inner, gently ribbed lobe with a minute solenomere at tip.Telopoditomere 1 more strongly setose on front face, telopoditomere 2 with two vestigial segments apically.

Vulva ( Fig. 1G ) rather short, densely pilose, receptacle process on operculum small but evident, curved, digitiform, slender.

REMARKS

Nepalella grandis n. sp. is amongst the largest species in the order Chordeumatida , and certainly the largest in Nepalella . This can also be associated with cave gigantism, as this animal is definitely troglobitic, showing such typical troglomorphisms as unpigmented ocelli and tegument, extremely long legs and antennae. The number of ocelli per eye patch is also reduced, especially in the female. However, because very long and slender antennae are characteristic of many, often definitely epigeic congeners, their value as a troglomorphic trait is highly limited.

This genus is well defined ( Shear 2002) and has hitherto been known to comprise 20 species or subspecies from Nepal (10), Thailand (2), Myanmar (2), Vietnam (1) and southern China (5). The only previous key dealt with 14 of these ( Mauriès 1988). With the addition of a further two congeners from Chinese caves, Nepalella can now be regarded as one of the most speciose genera among the oriental Chordeumatida . Considering all available descriptions ( Shear 1979, 1987, 1999, 2002; Golovatch 1983; Mauriès 1988), the following refined and updated key to Nepalella species is proposed. This will hopefully encourage further work on this remarkable genus, in which many other new species undoubtedly remain to be discovered.

Figures

FIG. 1. — A-C, Nepalella marmorata n. sp., paratype ♂; D-F, N. grandis n. sp., paratype ♂; G, N. grandis n. sp., paratype ♀; A, D, anterior body end, dorsal view; B, E, midbody segments, dorsal view; C, F, same, lateral view; G, vulva, front view. Scale bars: A-F, 2.0 mm; G, 0.4 mm.

FIG. 4. — Nepalella grandis n. sp., paratype ♂: A, antenna; B, leg 7, caudal view; C, leg 10, front view; D, leg 11, front view; E, leg 12, front view; F, anterior gonopods (leg-pair 8), caudal view; G, H, posterior gonopods (leg-pair 9), front and caudal views, respectively. Scale bar: A-E, 0.8 mm; F-H, 0.4 mm.