CERASOMMATIDIIDAE STAT. RESTORED WITHIN

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 : 1085-1086

THE PHYLOGENETIC PLACEMENT OF CERASOMMATIDIIDAE STAT. RESTORED WITHIN THE COCCINELLID LINEAGE OF COCCINELLOIDEA

The results from our molecular ( Fig. 1 ), morphological (Supporting Information, File S12a–c) and combined data (molecules and morphology) ( Fig. 2 ) analyses strongly and unambiguously support the status of Cerasommatidiidae as a distinct clade at the family level. Morphologically, the monophyly of Cerasommatidiidae is supported by several characters ( Fig. 2 ) (listed in Results) that set cerasommatidiids apart from Eupsilobiidae and other coccinelloid groups. In particular, the ovipositor lacking coxites is unique to this group and has not been found in any other Coccinelloidea . The sister-relationship of Cerasommatidiidae with Mycetaeidae is strongly supported in both the molecular and combined analyses. Yet, only one morphological, homoplastic character was recovered in the combined analyses as supporting this relationship: the mandible with subapical teeth or serrations (9:0). At this point it is difficult to elucidate shared morphological characters between members of these two families.

It is noteworthy that the position of Eupsilobiidae differs between the combined and molecular trees. In the molecular tree ( Fig. 1 ) it is recovered as the sistergroup to Coccinellidae with strong support (PP = 1.0), whereas in the combined analysis it forms the sistergroup to the Mycetaeidae + Cerasommatidiidae , although with low nodal support (PP = 0.69) and no corresponding anatomical synapomorphies.

The monophyly of Eupsilobiidae is supported by two uncontroverted synapomorphies: aedeagus with penis coiled (38:1) and ovipositor with infundibulumlike structure/sperm duct modified (41:1) and by one homoplastic character: labial mentum with large, triangular, raised area (11:2). The position of Eupsilobiidae within the coccinellid group, as well as the internal family relationships, remains uncertain and ought to be readdressed in future studies. The genus Chileolobius , the only member of Eupsilobiidae represented in the molecular analysis, was supported in our combined data analysis as sister-group to the rest of Eupsilobiidae (‘core Eupsilobiidae’ composed of Eidoreus , EƲolocera , Microxenus and Natalinus ). This result could be an artefact of the remaining eupsilobiid exemplars being represented in the combined data analysis by morphological data only. However, Chileolobius is an enigmatic taxon, exhibiting several morphological features shared with all or some Coccinellidae but no other Eupsilobiidae , including frontoclypeal suture absent (6:0), mandibular mola absent or reduced (7:1) and mesotrochantin concealed (28:1). The core eupsilobiids are recovered with strong nodal support (PP = 0.99) and multiple anatomical apomorphies, including antennae composed of ten articles (4:2) and mesotrochantin at least partially exposed (28:0). A closer relationship between Eidoreus and Microxenus , with respect to Chileolobius and Ibicarella , was previously hypothesized by Pakaluk & Ślipiński (1990). Including molecular data for exemplars of core Eupsilobiidae will be the next step to elucidate their relationships with Chileolobius and corroborate the position of Eupsilobiidae among the coccinellid group of families.

The results of this study demonstrate the separation of Cerasommatidiidae from Eupsilobiidae , and justify the restoration of this lineage to family status. Cerasommatidiidae are corroborated by both high topological support as the sister-group to Mycetaeidae in the molecular and combined analysis and by their unique morphological features, as outlined above.

The relationships between species of Cerasommatidiidae , as revealed by the morphological and combined analyses, justify the recognition of four genera despite an unclear relationship between them. Cerasommatidia in the new sense (including Ibicarella ) is a homogeneous group, with species differing only in the structures of the male genitalia, the body proportions and the degree of development of the pronotal border. A sister-relationship recovered for Cerasommatidia + MahaƲelo is based on single homoplastic character: labial palp with palpomere 2 oval, inflated (12:1) and is not strongly supported (PP = 0.83). Similarly, the sisterrelationship of Yamuy with Karumbe has negligible nodal support (PP = 0.47) and no morphological characters to bolster the relationship.

Figures

Figure 1. Results of the phylogenetic analysis of molecular data under Bayesian inference showing the position of Cerasommatidiidae status restored within Coccinelloidea. A summary tree of our molecular phylogenetic analyses using 236 taxa. Clades for each family/subfamily are collapsed. Statistical support for branches show posterior probabilities. The full-resolution tree is provided as in Supporting Information, File S11. Habitus pictures of the Cerasommatidiidae: MahaƲelo madagasus sp. nov. (lateral) and Yamuy marginatus sp. nov. (dorsal).

Figure 2. Results of the phylogenetic analyses of the combined, morphological and molecular dataset under Bayesian inference. Statistical support for branches show posterior probabilities. Branch lengths are kept and shown in the same proportion all along the tree. Apomorphies tracked in WINCLADA are shown upon each branch. DNA helix graphic after taxon name indicates taxa for which molecular data were available; asterisk ‘*’ indicates interspecific chimeras (combined data from two different species of the same genus).