Morettius, Roggero & Dierkens & Barbero & Palestrini, 2017

GENUS MORETTIUS View in CoL GEN. NOV.

Type species: Onthophagus pallens d’Orbigny, 1908

Included species: M. pallens ( d’Orbigny, 1908) , and M. utete sp. nov.

Diagnosis: Species of the genus Morettius ( Fig. S3 – Appendix 4, Supporting Information) are characterized by the mostly rounded and only slightly notched anterior margin of the clypeus, and the pronotum covered by granules, sometimes mixed to points. The pygidium is always smooth, with some rade points. The species show a moderate sexual dimorphism in the fore tibiae, and the pygidium is larger in males than in females.

Epipharynx: The epipharynx ( Fig. 2) fore margin is arched, with a largely V-shaped notch in the middle. The corypha is reduced, the chaetopariae are arched with short, thick and almost equal-length setae. The pubescence of the haptomerum is dense. The proplegmatium is subequal along the whole length, with the posterior triangular sclerotization reaching at least as much or more than half the length of the anterior epitorma, which is rectilinear, well sclerotized and thin. The base of the triangular sclerotization reaches the small, thick and upwardturned apophyses. Laeotorma and dexiotorma are symmetrical, short and stout. Pternotormae are well sclerotized, and the crepis is short but evident, with a sharp apex. The plegmatic area is visible.

Male genitalia: Only the male genitalia of M. pallens could be examined. The phallobase ( Fig. 7) is short, only slightly arched, slender and of equal size along the whole length. The parameres are symmetrical, and squared, with a small tip at the apex, and a small, rounded protrusion ventrally. The internal sac ( Fig. 8) is membranous, with various well-sclerotized parts differing greatly from Hamonthophagus species.

Female genitalia: The female genitalia are very peculiar ( Fig. 11), as the vagina of both species is entirely membranous, and no sclerotization is present at all. Furthermore, the infundibular tube is lowered as in Hamonthophagus , but here an expanded portion is identifiable in the central part of the vagina, which is differently shaped in the two species. The receptaculum seminis is sickle-shaped, namely slim, arched and apically sharp ( Fig. 9).

Specific diagnosis: These species can be easily distinguished on the basis of external morphology, epipharynx and female genitalia.

The pronotum in M. pallens is covered by distinct rasping points mixed with smaller, yellow granules; the granules of the rasping points instead are large, darker than the background surface, and carry long, thick and light yellow setae. The pronotum of M. utete is covered by only a few rasping setigerous points with thin, yellow setae and many small granules, which are very thick, evenly coloured as the base and without points.

Elytral striae of M. pallens are as large as the points, being instead larger than the points in M. utete .

The smooth pygidium carries in M. pallens few, small, rade and deep setigerous points that are not granulated, and in M. utete only some large and superficial vanishing points without setae.

The epipharynx (see Fig. 2 for a comparison among species) has the characteristic shape of Morettius species, but can be distinguished from M. utete by the more developed apotormae, and the more slender laeotorma and dexiotorma.

In both species, the vagina is wholly desclerotized, but carries two globose symmetrical expansions that encircle the desclerotized and lowered infundibulum in M. pallens , while in M. utete there is a single, large expansion (see Fig. 11 for a comparison among species).

As the male of M. utete is unknown, no comparison can be made between species.

General remarks: No preimaginal stages have been described so far.