Cerasommatidia Brethes 1925
Creators: name: Arriaga-Varela, Emmanuel
name: Tomaszewska, Wioletta
name: Szawaryn, Karol
name: Robertson, James
name: Seidel, Matthias
name: Ślipiński, Adam
name: Fikáček, Martin
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Cerasommatidiidae
Cerasommatidia

description: CERASOMMATIDIA BRÈTHES, 1925
(FIGS 3–5)
Cerasommatidia Brèthes, 1925: 199.
Type species, by monotypy, Cerasommatidia arroaei Brèthes, 1925. – Pakaluk et al., 1994: 228; Shockley et al., 2009: 27.
Ibicarella Pakaluk & Ślipiński, 1990: 717, synon. nov.
Type species, by original designation, Ibicarella plaumanni Pakaluk and Ślipiński, 1990. – Pakaluk et al., 1994: 228; Shockley et al., 2009: 27.
Diagnosis: Cerasommatidia can be separated from other genera of Cerasommatidiidae by the following combination of characters: dorsal surface of the body covered by inconspicuous tiny decumbent hairs (often broken or missing) (Figs 3A, B, 4D, 5C, G), pronotum with anterior and lateral sides narrowly marginate (Figs 4B, 5C); prosternal process moderately wide (Fig. 5D); trochanters flattened and expanded posteriorly to cover the tibio-tarsal joint in repose (Figs 4E, G, 5H); abdominal ventrite 1 with complete, semicircular postcoxal lines (Figs 3E, 4G, 5H); aedeagus with tegmen membranous, not fused with penis (Fig. 3E, F). Cerasommatidia resembles MahaƲelo in the body shape, coloration, short, inconspicuous dorsal vestiture and the pronotal lateral margins without internal carina. However, it can be distinguished from the later by having the prosternal process with a pair of lateral carinae extending anteriorly beyond level of anterior margin of procoxal cavities (a single, long, median, longitudinal carina present in MahaƲelo), hind angles of pronotum without indentation (in MahaƲelo hind angles of pronotum possess small indentation to receive humeral corner of elytron), scutellar shield visible (invisible/absent in MahaƲelo) and complete semicircular femoral lines in the abdominal ventrite 1.
Description: Length 1.15–1.70 mm. Body moderately short oval, convex, 1.3–1.4 times as long as wide, 1.8–1.9 times as long as high. Coloration homogeneous: dark brown to black (Fig. 3A, B).
Head with dorsal surface uniformly covered with short fine setae (Figs 4A, 5A). Clypeus large, rectangular. Frontoclypeal suture present but feebly marked, almost straight. Ventral antennal grooves short, reaching close to posterior eye level (Fig. 5B). Antenna approximately 0.35 of length of body (Figs 3A, C, 5E); antennal club one quarter of total antennal length; antennomeres 1–5 longer than wide, with antennomere 5 longer than antennomere 6; antennomeres 6–9 variable. Eyes comparatively small, moderately prominent (Figs 3C, 4A, 5A). Galea large, densely setose apically. Lacinia weakly narrower than galea with dense setae at apex and inner margin. Labium (Fig. 5B) with mentum widest near midlength or basal third, palpomere 2 and 3 large, bulbous, somewhat oval and subrectangular respectively; terminal palpomere short and subtruncate to weakly elongate, acuminate, 1.2–1.5 times as long as wide.
Prothorax. Pronotum 2.2–2.5 times as wide as long, widest at base and strongly convergent anteriorly, 1.9–2.2 times wider at widest part than on front angles (Figs 4B, 5C). Anterior margin (at least partly) and lateral margins narrowly bordered; base of pronotum regularly rounded, without distinct bordering line or with faint bordering line present medially. Pronotal sides scarcely rounded; hind angles without indentation to receive humeral corner of elytron. Pronotal disc moderately convex, smooth, with sparse fine punctures provided with thin, tiny hairs. Prosternum (Fig. 5D) with anterior margin weakly arcuate posteriorly; prosternal process extending posteriorly to hind level of procoxae, comparatively wide, at apex about 0.7–0.8 of the width of procoxal cavity; with raised lateral carinae reaching anteriorly well beyond level of anterior margin of procoxal cavities; area between carinae weakly concave. Hypomeron with deep, long, straight antennal grooves (Fig. 5D).
Pterothorax. Mesonotum with scutellar shield small, transverse, weakly rounded at apex (Fig. 5C). Mesoventrite (Figs 3D, 4E, 5H) with intercoxal process smooth, almost flat with anterior raised border incomplete medially; 1.2–1.4 times as wide as mesocoxal diameter. Metaventrite (Figs 3D, 4E, 5H) as long as abdominal ventrites 1–3 together; with remnants of discrimen posteriorly; anterior margin with bordering carina widening towards lateral corners; central area with small to large and deep setiferous punctures. Anterior part of metanepisternum with small outer blunt like projection (Fig. 3D). Elytra 0.85–1.00 mm long (Figs 3A, 4C, 5G), about as long a wide, 2.9–3.3 times as long and 1.2 times as wide as pronotum, with lateral margins narrowly explanate. Surface with small setiferous punctures bearing tiny, thin setae. Epipleura almost reaching elytral apex but incomplete, narrow, with internal bordering line narrow, present from the level of mid coxae to apex. Hindwings reduced or absent.
Legs (Fig. 3D). Trochanters angulately produced posteriorly. Meso- and metatrochanters with posterior margin as a conspicuous laminar expansion that covers tibio-tarsal joint in repose. Femora flattened (mid and hind femora more distinctly than fore femora); with grooves for tibiae present throughout whole length. Claws with comparatively small blunt tooth at base (Figs 4F, 5F).
Abdomen (Figs 3E, 4G) with ventrite 1 anteriorly with bordering carina forming distinct, rounded and complete laterally postcoxal lines, extending posteriorly beyond midlength of ventrite 1.
Male genitalia (Fig. 3E, F). Aedeagus with penis long and narrow, sclerotized, curved or asymmetrically sinuate, not-ramificate apically. Tegmen: large, in form of submembranous ring; tegminal strut long, membranous, flattened.
Female genitalia not studied.
Species included: Cerasommatidia arroaei Brèthes, 1925, C. plaumanni (Pakaluk & Ślipiński, 1990), C. rotundata (Pakaluk & Ślipiński, 1990).
Distribution: Brazil (Fig. 20B).
Comment: When Pakaluk & Ślipiński (1990) described Ibicarella in Eupsilobiinae they were not aware of its resemblance to Cerasommatidia Brèthes, 1925. Subsequently, when the holotype of Cerasommatidia arroaei was rediscovered its resemblance with Ibicarella was noticed and served as basis for the synonymy of Cerasommatidiidae under Eupsilobiinae (Pakaluk et al., 1994). Nevertheless, in part due to the state of preservation of the holotype of C. arroaei, its morphology was not thoroughly studied and both Cerasommatidia and Ibicarella were retained as valid genera. In the present study, we carefully examined the morphology of the type material of all Cerasommatidia and Ibicarella species and, following the results of our morphological (Supporting Information, File S12a–c) and combined (Fig. 2) analyses, we consider both represent the same genus and Ibicarella Pakaluk & Ślipiński is considered a subjective junior synonym of Cerasommatidia Arrow.
description: Published as part of Arriaga-Varela, Emmanuel, Tomaszewska, Wioletta, Szawaryn, Karol, Robertson, James, Seidel, Matthias, Ślipiński, Adam & Fikáček, Martin, 2023, The resurrection of Cerasommatidiidae, an enigmatic group of coccinelloid beetles (Coleoptera: Coccinelloidea) based on molecular and morphological evidence, pp. 1078-1115 in Zoological Journal of the Linnean Society 197 (4) on pages 1087-1091, DOI: 10.1093/zoolinnean/zlac082, http://zenodo.org/record/7814127