Date Published: August 13, 2014
Publisher: Public Library of Science
Author(s): Verônica Saraiva Fialho, Juliana Chamorro-Rengifo, Cristiano Lopes-Andrade, Karla Suemy Clemente Yotoko, Andreas Hejnol.
Listroscelidinae (Orthoptera: Tettigoniidae) are insectivorous Pantropical katydids whose taxonomy presents a long history of controversy, with several genera incertae sedis. This work focused on species occurring in the Brazilian Atlantic Forest, one of the world’s most threatened biomes. We examined material deposited in scientific collections and visited 15 conservation units from Rio de Janeiro to southern Bahia between November 2011 and January 2012, catching 104 specimens from 10 conservation units. Based on morphological and molecular data we redefined Listroscelidini, adding a new tribe, new genus and eight new species to the subfamily. Using morphological analysis, we redescribed and added new geographic records for six species, synonymized two species and built a provisional identification key for the Atlantic Forest Listroscelidinae. Molecular results suggest two new species and a new genus to be described, possibly by the fission of the genus Hamayulus. We also proposed a 500 bp region in the final portion of the COI to be used as a molecular barcode. Our data suggest that the Atlantic Forest Listroscelidinae are seriously endangered, because they occur in highly preserved forest remnants, show high rates of endemism and have a narrow geographic distribution. Based on our results, we suggest future collection efforts must take into account the molecular barcode data to accelerate species recognition.
Listroscelidinae (Orthoptera: Tettigoniidae) are carnivorous (insectivorous) katydids  with a long and controversial taxonomic history. In 1891, Redtenbacher  placed these species in the tribe “Listroscelini”, which he included in Conocephalinae, with Listroscelis Serville as the type genus. This tribe included a few genera now classified in two other subfamilies, Meconematinae and Hexacentrinae. In 1898, Saussure & Pictet  separated Listroscelis into “Listroscelites”, but examined only L. arachnoides Redtenbacher, the type-species of Arachnoscelis, further described by Karny . In 1906, Kirby  raised the tribe to the rank of subfamily and in 1915 Bruner  treated the group as a family and provided a taxonomic key for tropical American genera. In 1924, Karny  transferred a few genera to Meconematinae and in 1936 Zeuner ,  reevaluated Tettigoniidae, examining traditional characteristics of the head, wing venation and prothoracic tracheal apparatus. He proposed two closely related taxa: “Conocephaloids”, including Listroscelidinae (treated as a subfamily), Salomoninae (including Agraeciinae) and Copiphorinae; and “Tettigonioids”, including Tettigoniinae, Decticinae, Saginae, Mecopodinae and Phyllophorinae. In 1840, Zeuner  transferred Xiphidiopsis Redtenbacher, Phlugis Stål and Phlugiola Karny to Meconematinae but some doubts remained as he considered the differences between Meconematinae and Listroscelidinae to be only gradual. In 1979, Rentz  corrected the suprageneric name to Listroscelidinae, redefining it to include species with fastigium of vertex narrow and usually sulcated, fore and mid femora with robust spines and fore tibia with five to seven long spines.
After more than a century since Litroscelidinae katydids were recognized as a suprageneric taxon, they remain barely known to science, which may be attributed to the difficulties in collecting these animals. In addition, some species are aggressive (e.g. Monocerophora and Cerberodon species) and others are very fast (e.g. Hamayulus spp.), making it difficult to observe and collect them in the field. In addition to the high number of individuals collected (104), our samples had approximately five females to each male, making it difficult to identify and describe the species, which are preferably identified by males. No males of L. itatiaiasp. nov., L. carinatasp. nov. or M. spinosa were collected.
This is the first broad taxonomic and molecular work on Neotropical Listroscelidinae. Based on specimens collected in the Brazilian Atlantic Forest, as well as some specimens deposited in museums, we added a new tribe, a new genus and eight new species to the subfamily and redefined Listroscelidini. We redescribed and added new geographic records for six species, synonymized two species and built a provisional identification key for Listroscelidinae occurring in the Atlantic Forest. Only four Listroscelidinae genera remain unclassified: Arachnoscelis, with six described species from southern Central America and the westernmost portion of the southern Neotropics; the monospecific Liostethomimus Karny, described from southern Brazil (but the type-specimen is considered lost) and the monospecific Paralistroscelis Carl and Poecilomerus Karny, both occurring in Madagascar.