Calvarium Calvariellum
Creators: name: Zwick, Peter
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Scirtidae
Calvarium

description: Calvarium (Calvariellum), new subgenus
Type species: Calvarium (Calvariellum) hamifer, n. sp.
Diagnosis. Small (BL 1.7 − 2.2 mm), parallel-sided beetles exhibiting the before-mentioned generic characters but distinguished by the following:
• Head without subocular ridge, about 1.7 times wider across eyes than long from occipital foramen to anterior edge of frontoclypeus (Fig. 6).
• A transverse arched suture subdividing the gula (Fig. 6).
• Penis with wide triangularly excised pala, large trigonium, and simple parameroids (Figs. 24, 42), or parameroid tips caudally connected (Figs. 30, 36).
• Tegmen and parameres Y-shaped (e.g., Fig. 25), or parameres separate, no visible tegmen (e.g., Fig. 31). • T9 not sclerotized, only the long rod-like apodemes distinct. They may be connected by a membrane (Fig. 34), or completely separate (e.g., Fig. 23).
• T8 of two species with paired ventral appendages (Figs. 21, 29).
• S8 indistinct or very weak, S9 lightly sclerotized.
Description. Elongate, sides of elytra parallel. In dorsal view, almost no angle between elytra and pronotum, none between pronotum and head (Fig. 18). Head very wide, distance between eyes large. In frontal view, an eye, the labrum and the 1st antennal segment each occupy roughly 1/5 of total head width (Figs. 6, 7).
Antennal sulcus between eye and mouthparts deep, bordered by high crests. The medial crest runs from the inner edge of the antennal sulcus up to above the mandibular articulation. The frontal ridge above the scape turns into the outer crest which descends close to the eye. The outer crest eventually meets the subgenal ridge at the point where a short transverse branch connects it to an arched accessory suture (Fig. 7).
Antennal base as for genus. Scape a little longer than pedicel. Pedicel and first flagellar segment of similar length, segment 4 thin, cylindrical. Flagellum loosely structured, segments constricted at both ends. Last segment elongate oval (Fig. 19).
Mandibles symmetrical, with distinct tooth. Last segment of maxillary palpus short, bottle-shaped. Second segment of labial palpus curved, its end with the concave terminal segment directed mediad (Figs. 6, 8, 9). Prosternal process anteriorly parallel, caudally widened, rear edge regularly rounded (Fig. 20), sclerite punctate and finely pilose.
Receiving groove on mesoventrite wide, almost hexagonal, bordered by low ridges. Mesoventral process wide and short, not extending to rear edge of middle coxae which are widely separated by a finely bordered parabolic process of the metaventrite (Fig. 20). Ventral face of thorax with coarse setiferous punctures except in places where the femora rest. Discrimen of metaventrite complete.
Legs unmodified. Abdominal sternites unmodified. A few setiferous granules on the small triangle formed by S3 between the hind coxae, a long granule row along the front edge of S4.
Male. T8 with only microtrichia, no setal fringe (e.g., Figs. 29, 39). S8 weakly developed, V-shaped (Figs. 29, 33). Plate of T9 not developed, apodemes caudally prolonged, connected (Fig. 34) or separate (Figs. 23, 40). S9 with a slender base and an oval, caudally sparsely pilose bilobed or rounded plate (e.g., Figs. 23, 35). Penis stout, pala anteriorly wide, excised, with anterolateral corners (e.g., Figs. 24, 36). Trigonium and parameroids well developed, variable between species. The parameres are slender blades attached to a narrow handle-like tegmen (e.g., Figs. 25, 37).
Female. No hair tuft or other modification to abdominal sternites. T8 with long and strong apodemes, those of the hairless small S8 much shorter, thin, anteriorly connected by a loop. Ovipositor unmodified (Fig. 26), the long apodemes with short recurrent branchlet. Prehensor variably developed (Figs. 27, 28). No distinct pores on bursella or gonoduct.
Note. All four species agree with the foregoing description which is not repeated under individual species. Only short diagnoses of distinctive traits are provided, in order of descending similarity with the type species. By their genitalia, the species are recognized at a glance, no key is needed.
Etymology. Calvariellum, diminutive of Calvarium.
description: Published as part of Zwick, Peter, 2014, Australian Marsh Beetles (Coleoptera: Scirtidae). 6. Genera Calvarium Pic, Papuacyphon Zwick, and Ypsiloncyphon Klausnitzer, pp. 1-41 in Zootaxa 3846 (1) on pages 7-8, DOI: 10.11646/zootaxa.3846.1.1, http://zenodo.org/record/286792