Phelister parallelisternus Schmidt, 1893

Caterino, Michael S. & Tishechkin, Alexey K., 2019, A revision of the Phelisterhaemorrhous species group (Coleoptera, Histeridae, Exosternini), ZooKeys 854, pp. 41-88 : 53

Phelister parallelisternus Schmidt, 1893 Figs 2, 3; Map 2

Phelister parallelisternus Schmidt, 1893b: 86.

Type material.

Lectotype of undetermined sex, hereby designated: “Mexico” / "parallelisternus Sch." / "parallelisternum [sic]" / “Type” / "coll. J.Schmidt" / "LECTOTYPE Phelister parallelisternus Schmidt 1893, M.S. Caterino & A.K. Tischechkin des. 2010" (ZHMB); one paralectotype of undetermined sex is also designated at ZMHB: “Mexico”, and one at MNHN: "Mexique, col. Bickhardt".

Diagnostic description.

Length: 1.65-1.93 mm (avg. 1.78 mm); width: 1.22-1.58 mm (avg. 1.46 mm). Body elongate-oval, widest at humeri, humeri slightly wider than base of pronotum; body uniformly dark rufescent to piceous; frons finely but distinctly punctulate, somewhat depressed along midline; supraorbital stria complete, frontal stria interrupted across middle; labrum wide, distinctly emarginate apically; both mandibles with strong tooth on inner edges; pronotum with coarse ground punctation throughout, with larger punctures becoming more densely intermingled toward sides; prescutellar impression distinct; lateral and anterior marginal pronotal striae continuous, complete, slightly crenulate at front; submarginal pronotal striae absent; elytron with single, complete, crenulate epipleural stria, outer subhumeral stria present in apical one-third to one-half, inner subhumeral stria absent, dorsal striae 1-5 complete (5th rarely abbreviated from base); sutural stria present in posterior three-fourths; ground punctation of pygidium and propygidium similarly fine, propygidium with secondary punctures small, sparse, mostly separated by two to three times their widths; prosternal lobe with truncate to weakly emarginate anterior margin, with fine marginal stria; prosternal keel with two complete striae parallel and distinctly united by basal arch, variably connected anteriorly, with faint, secondary basal striae nearer procoxa, finely punctulate between in both sexes; mesoventrite distinctly projecting, marginal stria complete, crenulate, continued at sides by postmesocoxal stria which runs posteriad nearly to metepipleuron; mesometaventral stria complete, weakly crenulate, arched weakly onto basal one-fourth of mesoventrite, extended posteriad by lateral metaventral stria to near inner corner of metacoxa; metaventral disk with few secondary punctures anteromediad metacoxae; first abdominal ventrite with complete inner lateral stria, outer lateral stria nearly complete, often fragmented at base; protibia with apex obliquely truncate, outer margin weakly rounded, bearing 5-6 marginal spines; meso- and metatibiae weakly expanded to apex, mesotibia with ca. five marginal spines, more prominent toward apex, metatibia with distinct spines confined to apical fourth. Aedeagus with distinct ventral process, just basad middle, basal piece short, less than one-fourth total length; tegmen with sides rounded, widest just beyond middle, apices narrowly separated, apical emargination narrow and shallow; median lobe approximately one-half tegmen length, proximal apodemes thin near base, thickened toward gonopore.

Remarks.

This species is quite similar to P. affinis , but can be consistently distinguished by its parallel and rather narrowly separated prosternal striae, and its complete 5th dorsal stria. Its frontal stria is interrupted at the middle, but not at the sides, and it never appears to show any indication of a sublateral pronotal stria.

Biology.

The only indications of habits for this species come from a few Oklahoma specimens sifted from ‘bay’ litter. A couple of specimens were also collected using flight interception traps.

Distribution.

The known distribution of this species is oddly disjunct. The types and other early specimens (NHMUK) bear no more specific locality than Mexico. Yet all recent specimens we have seen are from the south-central United States, specifically Oklahoma, Arkansas, and Missouri. It is most surprising that no specimens have been seen from Texas. Records: USA: Arkansas: Faulkner; Missouri: Pike; Oklahoma: Latimer.