Ptomaphaginus troglodytes, Perreau, Michel & Ruzicka, Jan, 2018

Perreau, Michel & Ruzicka, Jan, 2018, Ptomaphaginustroglodytes sp. n., the first anophthalmic species of Ptomaphaginina from China (Coleoptera, Leiodidae, Cholevinae, Ptomaphagini), ZooKeys 749, pp. 135-147 : 137-143

Ptomaphaginus troglodytes sp. n. Figs 1, 2-5, 6-11, 15-19, 20

Type locality.

China: Guizhou Province, Libo Xian County, Shuiboshu Dong cave [ca. 25°29'05"N, 107°52'54"E], 490 m.

Material examined.

Holotype male (NSMT): "Shuiboshu Dong cave (490 m) / Shuipu cun [ca. 25°29'05"N, 107°52'54"E], Yuiping Zhen / Libo Xian // (Guizhou, CHINA) / 13.ix.1997, T. Kishmoto [leg.] // HOLOTYPUS / Ptomaphaginus troglodytes sp. n. / M. Perreau & J. Růžička, 2018". Paratypes (NSMT, JRUC, MPEC): 1 male and 2 females, same data; 1 male and 1 female, "Yamen Dong cave [ca. 25°29'N, 107°54'E] / Shuibo Zhai, Shuipu Cun / Libo Xian // (Guizhou, CHINA) / 13.ix.1997, T. Kishmoto [leg.] // PARATYPUS / Ptomaphaginus troglodytes sp. n. / M. Perreau & J. Růžička, 2018".

Description.

Length 1.85 mm. Body widely ovoid, uniformly light brown (depigmented). Body covered with recumbent setae inserted along tight transverse strigae (Fig. 5). Habitus in Figs 1, 2.

Head without eyes (Fig. 3), antenna slender, the club weakly dilated (Fig. 4), the ratio of the lengths of antennomeres to the length of the first one are as follows: 1.00, 0.60, 0.36, 0.26, 0.31, 0.29, 0.45, 0.19, 0.38, 0.45, 1.07. Mandibles with two teeth along the internal side (Fig. 9). Maxillary palpus with the apical segment slender and very elongated, slightly longer than the penultimate (Fig. 8).

Pronotum transverse, 1.6 times wider than long, the largest width just before the base. Lateral sides arcuate, the posterior angles clearly protruding behind the posterior margin. Pronotal surface with transverse microstrigae.

Elytra short and wide, as long as wide, the greatest width near the base. Surface covered with transverse microstrigae, similar to that of the pronotum (Fig. 5). One incomplete parasutural longitudinal stria, extending over the basal half of the elytral length.

Mesoventral process with a high, widely rounded medial carina (Fig. 6). Metaventrite with lateral metaventral sutures slightly convergent symmetrically toward the central axis of the body. Metatergum long and thick, extending approximately half the length of the elytra (Fig. 18).

Protibia with a row of regular spines along the external side and with a second internal row on the ventral side, with one spine situated basally and a line of seven spines medially (Fig. 10). Mesotibia and metatibia with a comb of equal-sized spines around their apex (Fig. 11). Tarsal formula 5 –5– 5 in both sexes. Male protarsi widely dilated, as wide as the apex of the protibia. Female protarsi slightly dilated.

Male genital segment with a spiculum gastrale extending beyond the anterior margin of epipleurites on one third of its length and slightly narrowed on this part (Fig. 17). Latero-posterior margin of the epipleurites with a row of moderately strong setae (Fig. 17). Aedeagus with parameres fused laterally to the median lobe, tegmen without basal blade, the median lobe 2.6 times as long as wide, the apex roughly triangular in dorsal view (Fig. 15), with two lateral rows of eight strong and long setae inserted perpendicularly to the main plan of the aedeagus, and a preapical lateral row of four tiny setae (Fig. 16). Endophallus with a long, thick stylus, thicker at the base and getting progressively thinner from the base to the apex, with transverse stria in the distal half (Fig. 15).

Female abdominal segment IX with short gonocoxites (Fig. 19). Spermatheca uniformly sclerotized, spermiduct short and straight, spermathecal gland small (Fig. 19).

Diagnosis.

Distinct from other Ptomaphaginus in the absence of eyes, short, wide body shape, especially the elytra as wide as long (taken together), more developed setation of the aedeagus, and transverse microstrigae of the elytra which are extremely tight and orthogonal to the suture, not oblique as generally in Ptomaphagini .

The identification table of Chinese species of Ptomaphaginus given in the revision of the genus by Wang and Zhou (2015) should be modified by adding the first couplet before all others:

Figs 12-14 illustrate some characters of a Chinese epigean species of Ptomaphaginus to compare with P. troglodytes : Fully developed eyes (Fig. 12), mesoventral process less elevated (Fig. 13) and ventral face of protibia with the second row of spines more regular (Fig. 14).

Etymology.

Cave-dweller in Latin, because of the association of the new species with caves; noun in apposition.

Biology and biogeography.

No bionomic details are available for the two small series, collected in Shuiboshu Dong and Yamen Dong caves. This is the first species of Ptomaphaginus reported from Guizhou Province, most probably as a result of a gap in knowledge of the fauna of the centre of southern China (see Wang and Zhou 2015: 336, figure 20); this may be improved by additional sampling activities.

Distribution.

The species is presently known only from two closely situated caves in Libo Karst area, south of Guangxi Province, China (Fig. 20).