Sinodiapterna zeni ( Ochi, 1991 )

Wang, Chuan-Chan, 2017, The genus Sinodiaptera Dellacasa (Coleoptera: Scarabaeidae: Aphodiinae) in Taiwan, Zootaxa 4320 (1), pp. 68-80 : 71

Sinodiapterna zeni ( Ochi, 1991)

Figs. 1–2 , 5–6 , 9, 11 , 13 , 15 , 17–18 , 23 , 26, 28

Specimens examined. TAIWAN. Taoyuan County: Sulo , 24 June 1972, B.- S. Chang (1 male, 1 female, NMNS).

Redescription. Male ( Fig. 1 ). Body length 6.1 mm; width across humeri 3.0 mm. Color black, shiny, with antennae, mouthpart, and legs reddish black. Head: Epistoma strongly rugopunctate, frons with large punctures in uneven distribution; clypeofrontal suture distinctly ridged; forns with a small tubercle centrally ( Fig. 11 ). Clypeus slightly sinuate between dentate angles, angles moderately reflexed when viewed laterally ( Fig. 9 ). Genae obtusely angulate. Thorax: Pronotum widest at middle, surface with small and large punctures mixed; large punctures sparsely distributed and irregularly spaced; small punctures nearly evenly distributed; lateral margin beaded, posterior margin well-defined, beaded ( Fig. 13 ) with smooth part in front of scutellum; lateral declivities absent; anterior and basal margins smooth; hind angles rounded, slightly protrudent. Scutellum ( Fig. 15 ) narrowly elongate, base wider than elytral interval, quarter as long as elytra; punctures same as those on pronotum, number of large punctures far less than small punctures. Prosternal process longitudinally raised, covered with yellow setae. Elytra: Disc only with small punctures, similar to those on pronotum, with a few large punctures on sides of elytra; striae deeply impressed, punctate, punctures widely spaced; intervals feebly convex; humerus rounded. Venter ( Fig. 5 ): Punctures on ventral side large, setigerous, with exception of those on mesosternum, setae robust and long. Anterior margins of sternites 1–6 smooth with surface of sternites punctate; punctures setigerous, large in size, evenly spaced; setae on sides of sternites longer. Pygidium wider than long, slightly convex along midline; surface punctures setigerous, setae on apical margin longer than those on disc; punctures at apical half confluent. Legs: Protibia ( Fig. 17 ) tridentate with spur spatulate. Surface of profemora, mesofemora, and metafemora with setigerous punctures sparsely and irregularly distributed, setae along basal margin longer; protrochanter with a tuft of long setae at base, mesotrochanter and metatrochanter bearing setae along anterior margin; metafemora transverse, moderately broadened and convex at middle; inner margin of metatibia becoming curved and broadened anteriorly with sparse, long setae at inner side of apical half; metatibial superior spur sharp, slightly longer than metatarsomere 1 ( Fig. 23 ), metatarsomere 1 as long as metatarsomeres 2–4 combined. Genitalia: Parameres with apical parts roundly curved when viewed laterally ( Fig. 28 ), tapering anteriorly, tip broadened in an arrow shape ( Fig. 26 ).

Female ( Figs. 2 , 6 ). Body length 6.2 mm; width across humeri 3.1 mm. Protibia ( Fig. 18 ) with apical, middle, and basal tooth longer than in male; tibial spur sharply prolonged with tip slightly curved outwardly; protrochanter glabrous; inner margin of metatibia almost straight.

Diagnosis. Based on comparison of morphological characters, Sinodiapterna zeni most closely resembles S. troitzkyi . Both species can be separated by: size of body usually larger in S. zeni (usually smaller in S. troitzkyi ); posterior margin of pronotum with weakly-defined bead in S. zeni ( Fig. 13 ) (well-defined bead in S. troitzkyi ( Fig. 14 )); punctures of elytral striae well spaced in S. zeni (strial punctures tightly spaced in S. troitzkyi ); elytral intervals flat in S. zeni (elytral intervals slightly convex in S. troitzkyi ); and metatibial superior spur slightly longer than metatarsomere 1 ( Fig. 23 ) (distinctly longer than basimetatarsomere in S. troitzkyi ( Fig. 24 )).

Distribution. Northern and central Taiwan.

Chinese name: AEHMḎĤẘ.

Remarks. Ochi (1991) only compared Japanese specimens with Taiwanese specimens to describe and name Sinodiapterna zeni . The diagnosis between S. zeni and S. troitzkyi we made above is based on the examination of specimens of the later species from Japan (Tokushima Prefecture). However, the true identity of S. troitzkyi population in Japan is still awaiting clarification (Andrey Frolov, personal communication). Any conclusion about the true identity of Sinodiapterna species in Japan should be based on comprehensive comparisons for all species in the S. troitzkyi species group. Over 90 type specimens of Sinodiapterna zeni were designated in the original description of the species, however, no biological information was provided ( Ochi 1991). Masumoto (1977) reported that S. zeni in Taiwan (under the name Aphodius troitzkyi ) fed on cow and/or sheep dung based on collecting observations at the type locality of S. zeni . Additionally, the adult activity of S. zeni is from April to December based on published specimen information (e. g., Nomura 1973; Masumoto 1977; Ochi 1991).

Figures

FIGURES 1 – 4. Dorsal habitus of Sinodiapterna species. 1 – 2, Sinodiapterna zeni; 3 – 4, Sinodiapterna yushana. 1, 3, male; 2, 4, female; 3, holotype.

FIGURES 5 – 8. Ventral habitus of Sinodiapterna species. 5 – 6, Sinodiapterna zeni; 7 - 8, Sinodiapterna yushana. 5, 7, male; 6, 8, female; 7, holotype.

FIGURES 9 – 12. Lateral view and head of male Sinodiapterna species. 9, 11, Sinodiapterna zeni; 10, 12, Sinodiapterna yushana. 9, 10, lateral view; 11, 12, head.

FIGURES 13 – 14. Left base of pronotum of male Sinodiapterna species. 13, Sinodiapterna zeni; 14, Sinodiapterna troitzkyi (Tokushima Prefecture, Japan).

FIGURES 15 – 16. Scutellum of male Sinodiapterna species. 15, Sinodiapterna zeni; 16, Sinodiapterna yushana.

FIGURES 17 – 20. Right protibia of Sinodiapterna species. 17 – 18, Sinodiapterna zeni; 19 – 20, Sinodiapterna yushana. 17, 19, male; 18, 20, female.

FIGURES 23 – 25. Metatibial superior spur (indicated by arrow) and metatarsus of male Sinodiapterna species. 23, Sinodiapterna zeni, right metathoracic leg; 24, Sinodiapterna troitzkyi (Tokushima Prefecture, Japan), left metathoracic leg; 25, Sinodiapterna yushana, right metathoracic leg.

FIGURES 26 – 29. Parameres of Sinodiapterna species (26 – 27, dorsal view; 28 – 29, lateral view). 26, 28, Sinodiapterna zeni; 27, 29, Sinodiapterna yushana. Scale bar: Figs. 26 – 27 = 0.25 mm, Figs. 28 – 29 = 0.5 mm.