Most firefly genera have poorly defined taxonomic boundaries, especially in the Neotropics, where they are more diverse and more difficult to identify. Recent advances that shed light on the diversity of fireflies in South America have focused mainly on Atlantic Rainforest taxa, whereas lampyrids in other biomes remained largely unstudied. We found three new firefly species endemic to the Amazon basin that share unique traits of the male abdomen where sternum VIII and the pygidium are modified and likely work as a copulation clamp. Here we test and confirm the hypothesis that these three species form a monophyletic lineage and propose Haplocauda gen. nov. to accommodate the three new species. Both maximum parsimony and probabilistic (Bayesian and maximum likelihood) phylogenetic analyses confirmed Haplocauda gen. nov. monophyly, and consistently recovered it as the sister group to Scissicauda, fireflies endemic to the Atlantic Rainforest that also feature a copulation clamp on abdominal segment VIII, although with a different configuration. We provide illustrations, diagnostic descriptions, and keys to species based on males and females. The three new species were sampled from different regions, and are likely allopatric, a common pattern among Amazonian taxa.

Cratomorphus Motschulsky, 1853 includes 38 species restricted to the Neotropical region. Based on adult males from Mexico, Cratomorphus leoneli sp. nov. is herein described from the states of Oaxaca, Campeche and Chiapas.We place the new species in Cratomorphus’ group IV, which includes species with the posterior border of sternite VIII medially produced. The new species can be distinguished from other species of the group IV by the clypeussubquadrate, posterior margin of pygidium bisinuate and posterior margin of sternite VIII with an apically obtuse median projection. Illustrations of habiti and diagnostic traits are provided, along with an identification key and adistribution map for the group IV species.

Fireflies (Coleoptera: Lampyridae) spend most of their lives as larvae. Nevertheless, immature stages of over 99% of species remain unknown, which gives an incomplete picture of the species' biology. Moreover, fireflies are most diverse in Central and South America, where most species remain known from the centuries-old taxonomic descriptions based on male morphology. Here, we redescribe the spotted tortoise firefly, Aspisoma stictucum Gemminger, 1870 based on immature and adult stages, provide illustration of diagnostic features and an updated distribution map. A definitive diagnosis of adult A. sticticum among congeneric species remains elusive due to lack of comparative studies, but the following combination of traits allow for discrimination of co-occurring species: size large (2–4 cm); pronotum and elytron testaceous with variable developed black spots, pronotum subtriangular; elytron widest at basal third. A. sticticum larvae is unique among fireflies in having paired pronotal lantern spots, in addition to the typical abdominal lantern spots. In fact, these sets of larval lanterns have independent control, as observed in the field and in the lab. Noteworthy, the pronotal lanterns cannot be seen in dead specimens, which stresses the need for field studies towards a deeper and more comprehensive understanding of fireflies.

New World lampyrid taxonomy faces severe taxonomic impediments. Most species remain known from original taxonomic descriptions only, often insufficient for accurate identification. Therefore, the study of type specimens is critical to ensure proper identification. The Russian entomologist Viktor Ivanovich Motschulsky was one of the most important authors of firefly (Coleoptera: Lampyridae) taxonomy during the XIXth century, and his work is still relevant today. Part of his material, including the type specimens of several species, is deposited at the Zoological Institute of the Russian Academy of Sciences. Unlike their European, Asian, and Oceanian counterparts, the taxonomy of Neotropical fireflies is still in its infancy, partly due to largely outdated literature and difficulties in accessing type specimens. Here, we review the type specimens of 38 firefly species deposited at ZIN, 15 of which are holotypes and 7 are lectotypes. For each specimen, the name-bearing status, condition of preservation, as well as the associated label data are provided. Lectotypes are designated for the following species described by Motschulsky: Bicellonycha lividipennis, Ellychnia californica, Lychnuris klugii, Macrolampis longipennis, Pseudolychnuris suturalis, Telephoroides lineaticollis, Telephoroide occidentalis.

The genus Lucio Laporte, 1833 is comprised of 16 species distributed throughout the Neotropics and is characterized by the presence of biflabellate antennae with asymmetric lamellae. In Brazil, there are nine species whose morphology has not been further explored taxonomically since the original description, many of them short, ambiguous and without illustrations, making the species identification in the genus difficult. Here, we provide a taxonomic review of Lucio pictum (Gorham, 1880) based on the examination of the holotype and 24 adult specimens. We provide a redescription of the male, description of the female (sexual dimorphism), illustrations, distribution map with new records for South America (Brazil and Peru) and notes on the biology. Additionally, we provide photographs of the Lucio rufiventris Olivier, 1885 and L. castelnaui (Kirsch, 1865) types.