Parachorius hookeri Arrow, 1931

Tarasov, Sergei, 2017, A cybertaxonomic revision of the new dung beetle tribe Parachoriini (Coleoptera: Scarabaeidae: Scarabaeinae) and its phylogenetic assessment using molecular and morphological data, Zootaxa 4329 (2), pp. 101-149 : 125-126

Parachorius hookeri Arrow, 1931

( Figs. 12 , 26A )

Parachorius hookeri Arrow, 1931: 359

Parachorius hookeri ; Balthasar, 1963: 277 Parachorius hookeri ; Bacchus, 1978: 104

Type locality. Sikkim, northeast India.

Diagnosis. Given the shape of parameres with apex simple, widely rounded, and inferiorly angulate this species is similar to P. fungorum , P. newthayerae , P. globosus , and P. shuelkei . Based on external morphology this species is most similar to P. fungorum . The latter and P. hookeri can be differentiated from other species of abovementioned group by (1) clypeus with two indistinct teeth that are not notched laterally, (2) metatibia slightly sinuate, (3) frontal angles of pronotum rounded, and (4) wings normally developed. Parachorius hookeri subtly differs from P. fungorum by not having modified metathoracic legs and the absence of a serrate margin of the metatibia.

Taxonomic notes. The paramere shape in P. hookeri , P. fungorum , P. newthayerae , P. globosus , and P. shuelkei are almost identical. A larger series of specimens will be needed to assess intraspecific variation of P. hookeri , known only from a single male, in comparison to its close relative P. fungorum . Parachorius hookeri may just be a minor male of P. fungorum , with whom it has an identical shape of aedeagus, meaning that the two names should be synonyms.

However, I do not attempt to synonymize these names here, for the two reasons: (1) aedeagus shape is not an ultimate character for species delimitation in Parachorius as some species have similar aedeagus shapes despite being drastically different in external characters; (2) in addition, these two forms seems to have a disjunct distributions with P. hookeri occurring in northern India and P. fungorum occurring in southern China, Myanmar, and Indochina. Thus, at this point, given the distribution and characters differentiating P. hookeri and P. fungotum , I consider P. hookeri a separate species.

Description. Body. Body brown, dark, length 6 mm. Elytra uniformly colored.

Head. Clypeus with two indistinct teeth, outer margin of each tooth not notched basally.

Pronotum. Pronotum rounded laterally. Frontal angles rounded. Disc covered with punctures separated by 0.5– 2.0 puncture diameter(s). Pronotum in anterior-posterior direction notably shorter than elytra.

Elytra. Elytra covered with sparse punctures.

Wings. Wings normally developed.

Legs. Profemur with almost straight or sinuate anterior margin. Protibia with apical spur approximately reaching middle of protarsomere 3. First tooth almost not modified in males, approximately as wide as second tooth, first and second teeth distinctly separated from each other; first tooth distinctly separated from denticles located between first and second teeth. Metafemoral posterior margin not serrate, simple, not modified. Metatibia slightly sinuate, inner margin not denticulate, straight, not produced apically.

Metasternum. Transverse basal ridge of metasternum long, at least 1/5 of mesocoxa length.

Aedeagus. Parameres symmetrical, simple, apex widely rounded and inferiorly angulate.

Material examined. Holotype: India: 1 male, “ Holotype / n Ind / Parachorius hookeri type Arrow / Parachorius hookeri Arrow M.E. Bacchus det. 1975 HOLOTYPE / Parachorius hookeri Arrow, 1931 S. Tarasov det. 2010” [Sikkim] ( BMNH).

Figures

FIGURE 12. Morphology of Parachorius hookeri. (A) aedeagus, lateral view (holotype). (B) aedeagus lateral view. (C) left metafemur (male, holotype). (D) habitus (male, holotype)

FIGURE 26. Distribution maps of Parachorius species. (A) Parachorius hookeri. (B) Parachorius humeralis. (C) Parachorius javanus. (D) Parachorius longipenis. (E) Parachorius maruyamai. (F) Parachorius newthayerae. Type locality — type locality of species (holotype or lectotype); Type. Collection data — localities of type specimens associated with species (paratypes or paralectotypes); Collection data — localities of other specimens examined in this study.