Cabamofa alexsmithi sp. nov., the second species of Cabamofa in Costa Rica (Diptera: Bibionomorpha: Sciaroidea incertae sedis)

Abstract

The genus Cabamofa Jaschhof previously contained three species: the type species C. mira Jaschhof from Costa Rica, and the Oriental C. orientalis Jaschhof & Ševčík from Thailand and C. vietnamensis Jaschhof & Levesque-Beaudin from Vietnam (Jaschhof 2005, Jaschhof & Ševčík 2019, Jaschhof et al. 2022). Here we describe a further Costa Rican member of the genus, C. alexsmithi Jaschhof & Levesque-Beaudin sp. nov. We analyzed the morphology of both sexes and obtained the COI barcode for the species. The specimens studied, two males and three females, were collected in the course of the inventory of the arthropod fauna of Área de Conservación Guanacaste, a World Heritage Site, northwestern Costa Rica (Janzen & Hallwachs 2016). The systematic position of Cabamofa within the Sciaroidea incertae sedis group of genera, recently reviewed by Jaschhof & Ševčík (2019), is not further discussed here since C. alexsmithi does not provide us with fresh insights in this respect. Size and shape of the new species are that of a typical Cabamofa (Fig. 1). In terms of adult morphology, C. alexsmithi is most similar to C. mira, the resemblance being as close as in the species pair from the Oriental region (Jaschhof et al. 2022). Positive species-specific distinctions, although still subtle, lie mostly in the genitalic structures of males. Morphological terms used here are in accordance with the overview given by Cumming & Wood (2017). The types of C. alexsmithi will be deposited in the Canadian National Collection of Insects, Arachnids, and Nematodes, Ottawa, Ontario, Canada (CNC). A morphological peculiarity of male Cabamofa not adequately addressed in the past is the structure of the two abdominal segments preceding the genitalia (see below the description of C. alexsmithi). Of both the seventh and eighth segments, the tergal portions are markedly shorter than the corresponding sternal portions (Fig. 2), giving the genitalia space for an upwards turn (Figs 1‒1A), probably during copulation. This peculiarity can be regarded as a generi