Unmasking a master of camouflage: The rich morphology, taxonomy, and biology of the Brazilian stick insect Canuleius similis (Phasmatodea: Heteronemiidae), with general considerations on phasmid genitalia

Abstract

Stick insects have received little attention in Brazil, with many taxa lacking taxonomic, biological and morphological information on the literature. This represents a gap of knowledge for inclusive groups in Phasmatodea and for the Neotropical diversity as a whole, including members of poorly known Pygirhynchini (Heteronemiidae). Canuleius similis Redtenbacher belongs to that lineage and is redescribed based on 123 individuals recently collected or raised in captivity. Bacteria ornata Brunner von Wattenwyl is found to be a junior synonym of C. similis. Lectotypes and paralectotypes are designated for Canuleius inermis Redtenbacher, of which part of the syntype series is assigned to C. similis. The male, female, nymphs and eggs were analyzed, illustrated and described. External macromorphology of mouthparts, cerci, tarsi, antennae and internal morphology of genitalia of both sexes, in special the male genitalia, were accounted for. The findings on male and female genitalia are discussed considering available information for Phasmatodea, including so far infrequently referenced works on Chilean species, hoping to shed more light in the understanding of genital structures in these insects. The male genitalia have common characters between Heteronemiidae and Pseudophasmatidae, indicating that the former may be a member of Occidophasmata. Female and male internal genitalia vary interespecifically and appear to be conservative in the same population. Traditional taxonomic characters, mostly related to camouflage, are shown to vary whereas detailed morphology is emphasized to be more conservative and encouraged to be included in future analyses. Additional information on habitat, behavior and development are given.