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The longhorn beetle tribe Dorcasomini exhibits remarkable endemism and species richness in Madagascar. Among the diurnal genera of Dorcasomini, Tsivoka Villiers, 1982 (Coleoptera: Cerambycidae) is distinguished by its coloration and elytral patterning. In this study, we present a taxonomic review focusing on Tsivoka, identifying a total of four species, including one species new to science: T. humeralis sp. nov.; T. peyrierasi Villiers, 1982; T. simplicicollis (Gahan, 1890); and T. testaceipes (Fairmaire, 1889). Descriptions, photographs, and a taxonomic key are provided for species identification. Additionally, we provide a distribution map for each species based on specimen information.  

Abstract Insect antennae are crucial sensory organs that house numerous sensilla with receptors for perceiving a wide variety of cues dominating their world. Historically, inconsistent terminology and criteria have been used to classify antennal sensilla, which has greatly impeded the comparison of data even across closely related species. Longhorn beetles (Coleoptera: Cerambycidae) are no exception to this quandary, and despite their prominent antennae, few studies have investigated their antennal morphology and ultrastructure, and none have compared sensillar diversity and variation among cerambycids. Existing studies of longhorn beetle antennal sensilla include only 29 species in five of the eight cerambycid subfamilies and include misidentified sensilla types and conflicting terminology. As such, it is very difficult to conduct comparative morphological studies of antennal sensilla in longhorn beetles and challenging to understand inter- and intra-specific variation in the sensory systems of these beetles. To facilitate future comparative studies, we reviewed all accessible published papers that have used scanning and transmission electron microscopy (SEM and TEM) to investigate antennal sensilla in cerambycids, and present a first attempt at standardizing the classification of their documented sensilla types and subtypes. Specifically, we discuss seven major types of antennal sensilla (Böhm bristles, sensilla chaetica, chemosensory hairs, sensilla basiconica, dome shaped organs, sensilla coeloconica, and sensilla auricillica). We also imaged the antennae of relevant species of longhorn beetles using SEM and included images exemplifying as many of the sensilla types and subtypes as possible.