Cerasommatidia, BRETHES, 1925

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, Zoological Journal of the Linnean Society 197 (4), pp. 1078-1115 : 1087-1091

publication ID	https://doi.org/ 10.1093/zoolinnean/zlac082
publication LSID	lsid:zoobank.org:pub:99842C3A-879F-4552-96B7-204D79CF3EDF
DOI	https://doi.org/10.5281/zenodo.7814159
persistent identifier	https://treatment.plazi.org/id/03C2CE00-FFF0-FF96-3D85-09BBFE1E4633
treatment provided by	Plazi
scientific name	Cerasommatidia
status

Treatment

CERASOMMATIDIA BRÈTHES, 1925

( FIGS 3–5 View Figure 3 View Figure 4 View Figure 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 View Figure 3 , 4D View Figure 4 , 5C, G View Figure 5 ), pronotum with anterior and lateral sides narrowly marginate ( Figs 4B View Figure 4 , 5C View Figure 5 ); prosternal process moderately wide ( Fig. 5D View Figure 5 ); trochanters flattened and expanded posteriorly to cover the tibio-tarsal joint in repose ( Figs 4E, G View Figure 4 , 5H View Figure 5 ); abdominal ventrite 1 with complete, semicircular postcoxal lines ( Figs 3E View Figure 3 , 4G View Figure 4 , 5H View Figure 5 ); aedeagus with tegmen membranous, not fused with penis ( Fig. 3E, F View Figure 3 ). 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 View Figure 3 ).

Head with dorsal surface uniformly covered with short fine setae ( Figs 4A View Figure 4 , 5A View Figure 5 ). Clypeus large, rectangular. Frontoclypeal suture present but feebly marked, almost straight. Ventral antennal grooves short, reaching close to posterior eye level ( Fig. 5B View Figure 5 ). Antenna approximately 0.35 of length of body ( Figs 3A, C View Figure 3 , 5E View Figure 5 ); 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 View Figure 3 , 4A View Figure 4 , 5A View Figure 5 ). Galea large, densely setose apically. Lacinia weakly narrower than galea with dense setae at apex and inner margin. Labium ( Fig. 5B View Figure 5 ) 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 View Figure 4 , 5C View Figure 5 ). 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 View Figure 5 ) 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 View Figure 5 ).

Pterothorax. Mesonotum with scutellar shield small, transverse, weakly rounded at apex ( Fig. 5C View Figure 5 ). Mesoventrite ( Figs 3D View Figure 3 , 4E View Figure 4 , 5H View Figure 5 ) 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 View Figure 3 , 4E View Figure 4 , 5H View Figure 5 ) 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 View Figure 3 ). Elytra 0.85–1.00 mm long ( Figs 3A View Figure 3 , 4C View Figure 4 , 5G View Figure 5 ), 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 View Figure 3 ). 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 View Figure 4 , 5F View Figure 5 ).

Abdomen ( Figs 3E View Figure 3 , 4G View Figure 4 ) 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 View Figure 3 ). 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 View Figure 20 ).

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 View Figure 2 ) analyses, we consider both represent the same genus and Ibicarella Pakaluk & Ślipiński is considered a subjective junior synonym of Cerasommatidia Arrow.