Ptomaphaminus granophilus, Perreau, Michel & Faille, Arnaud, 2015

Perreau, Michel & Faille, Arnaud, 2015, One new species of Ptomaphaminus Perreau, 2000 (Coleoptera: Leiodidae: Cholevinae: Ptomaphagini) from a granitic subterranean environment in Vietnam, Zootaxa 4021 (1), pp. 195-200 : 195-199

Ptomaphaminus granophilus n. sp.

( Fig. 3 )

Holotype. 1 male, Vietnam, granitic blockfield, Hon Ba, Suoi cat, 650 m, pitfall baited with vinegar, 20.IX 2013, A. Faille leg., deposited in Museum national d'Histoire naturelle de Paris, France.

Description. Length: 1.6 mm. General color light brown, antenna and protarsi yellowish.

Head. Eyes reduced, composed of approximately 40 ommatidia. Antennae slender, all antennomeres longer than wide except the eighth. The length of antennomeres (divided by the length of the first one) are: 1.00; 0.80; 0.35; 0.33; 0.30; 0.32; 0.45; 0.27; 0.50; 0.40; 0.87.

Pronotum transverse, 1.6 times wider than long, largest width near the base, sides parallel near the base. Surface covered with transverse strigae.

Elytra 1.35 times longer than wide together, as wide as the pronotum, largest width near the base. Surface covered with oblique (not strictly transversal) strigae, without longitudinal striae except the sutural one. Metasternal sutures convergent.

Protibiae with a longitudinal row of equal spines along outer margin, and with ventral spines randomly dispersed. Mesotibiae and metatibiae with a circular row of equal spines at apex. Tarsi pentamerous. Male protarsi dilated, 0.75 times as wide as protibias.

Urite IX with a long and narrow spiculum gastrale, protruding beyond the anterior edge of epipleurite IX by the apical half of its length which is imperceptibly widened ( Fig. 5 ). Aedeagus long and rather narrow, with parallel sides which are narrowly convergent at apex. Lateral apical expansions of the median lobe asymmetrical ( Fig. 4 ), the apex with a hook in lateral view ( Fig. 6 ). Internal stylus of the endophallus thin, helically winded in a single turn ( Fig. 4 ).

Female unknown.

Etymology. The epithet is from granum, latin origin of "granit", refering to the biotope where this species was found.

Discussion. The general morphology of this species, either external or internal, is typical of the genus Ptomaphaminus Perreau : median lobe of the aedeagus long, parallel, with the lateral apical expansions asymmetrical: the left one (which appears on the right side on pictures traditionally represented in reversed orientation) with a hook ventrally deflexed in lateral view. But it is evidently different from other species: aedeagus longer and narrower than P. bihamatus ( Szymczakowski, 1972) ( Figs. 7 ; 8), P. bedosae Perreau, 2009 ( Figs. 11, 12 ), P. deharvengi Perreau, 2009 ( Figs. 9 ; 10), P. boutini ( Jarrige, 1969) ( Figs. 13 ; 14) and P. leclerci ( Perreau, 1993) ( Figs. 15 ; 16), and the apex of median lobe with a different conformation. These five species are distributed not far from the type locality of the new species: the first two are known from Vietnam, the third from Laos, the fourth from Cambodia and the fifth from Thailand ( Fig. 17 ).

The biotope where the new species was discovered is remarkable. Ptomaphaminus granophilus n. sp. was found in a granitic blockfield made of huge, piled up blocks which are forming more or less important void spaces ( Figs. 1, 2 ) allowing to get through the screes and to go down several meters. The bottom is extremely wet and completely dark ( Fig. 2 ). During our visit, some water flowed there, forming a stream difficult to reach but clearly audible. In this peculiar biotope we also found most of the Arthropod groups common in the caves of limestones areas of the region: Orthoptera : Rhaphidophoridae , Araneae : Sparassidae , Hemiptera : Fulgoroidea of the families Cixiidae and Meenoplidae . The description of one of the species collected on hanging roots in the same blockfield is currently in progress.

The specimen was collected in the deepest reachable area of the blockfield, by means of a pitfall trap baited with vinegar. It is not excluded that the species will be found in the deep ground of the area. A second blockfield was localized at an altitude of 1500 meters behind the house of the bacteriologist A. Yersin who lived there until his death in 1943, close to the top of the massif. The new species was not found there, but these remarkable geological structures, forming a real subterranean environment in granitic area, would deserve to be inventoried and systematically sampled.

Figures

FIGURE 17. Distribution map of the genus Ptomaphaminus from Indo-China Peninsula.

FIGURES 1 – 3. Ptomaphaminus granophilus n. sp. 1 - 2: biotope: the granitic blockfield. 3: habitus.

FIGURES 4 – 16. Ptomaphaminus Perreau from Vietnam and Laos. 4: P. granophilus n. sp., aedeagus, dorsal view. 5: P. granophilus n. sp., male urite IX. 6: P. granophilus n. sp., aedeagus, lateral view. 7: P. bihamatus (Szymczakowski), aedeagus, dorsal view (from Szymczakowski, 1972). 8: P. bihamatus (Szymczakowski), aedeagus, lateral view (from Szymczakowski, 1972). 9: P. deharvengi Perreau, aedeagus, dorsal view. 10: P. deharvengi Perreau, aedeagus lateral view. 11: P. bedosae Perreau, aedeagus, dorsal view. 12: P. bedosae Perreau, aedeagus, lateral view. 13: P. boutini (Jarrige), aedeagus, dorsal view. 14: P. boutini (Jarrige), aedeagus, lateral view. 15: P. leclerci (Perreau), aedeagus, dorsal view. 16: P. leclerci (Perreau), aedeagus, lateral view.