Search

The Onthophagus brevifrons species complex (Coleoptera: Scarabaeidae: Scarabaeinae: Onthophagini) consists of the five species: Onthophagus cavernicollis Howden and Cartwright, Onthophagus subtropicus Howden and Cartwright, Onthophagus brevifrons Horn, Onthophagus cuevensis Howden and Onthophagus moroni Zunino and Halffter, all of which are strictly associated with underground habitats (caves or burrows) and are consequently considered troglobites. Nevertheless, the biology of Onthophagus Latreille species reported from caves is lacking. In this study, four grottoes in the Cuetzalan region were explored: Trompa de Elefante, El Fosil and El Nido del Murcielago (which belong to the poorly explored Gruta de Atepolihui), and the Tasalolpan cave, in the search for dung beetles. Onthophagus moroni was collected inside El Nido del Murcielago and Tasalolpan cave, representing a new record for El Nido del Murcielago, since its presence was previously recorded inside the Tasalolpan cave in 1988. Adults of O. moroni were collected alive 70 m inside the Tasalolpan cave, under a latrine of Peters' climbing rat, Tylomys nudicaudus (Peters) (Rodentia: Cricetidae). We redescribe the species, discuss its biogeography and provide an updated dichotomous key to enable the identification of the constituent species in the O. brevifrons species complex.

Megaloptera belong to a large monophyletic group, the Neuropteroidea, together with Coleoptera, Strepsiptera, Raphidioptera, and Neuroptera. With the latter two, this order constitutes the Neuropterida, a smaller monophyletic subset among which it is the only entirely aquatic group, with larvae of all species requiring submersion in freshwater. Megaloptera is arguably the oldest extant clade of Holometabola with aquatic representatives, having originated during the Permian before the fragmentation of Pangea, since about 230 Ma. It includes 54 genera (35 extant and 19 extinct genera), with 397 extant described species and subspecies. Recent Megaloptera are divided into two families: Corydalidae (with subfamilies Corydalinae—dobsonflies and Chauliodinae—fishflies) and Sialidae (alderflies), both widely yet disjunctively distributed among zoogeographical realms. All species of Megaloptera have aquatic larvae, whereas eggs, pupae, and adults are terrestrial. The anatomy, physiology, and behavior of megalopteran larvae are specialized for an aquatic predatory habit, yet their ecological significance might still be underappreciated, as their role in food webs of benthic communities of many temperate and tropical streams and rivers is still understudied and largely unquantified. In many freshwater ecosystems, Megaloptera larvae are a conspicuous benthic component, important in energy flow, recycling of materials, and food web dynamics.

As partial results of a long-term project for the revision of the supraspecific classification of the American Melolonthini, using phylogenetic methods, interesting information on the relationships between the subgeneric groups of Phyllophaga Harris proposed by Saylor were obtained. The genus Listrochelus was described by Blanchard in 1851. However, in 1940, Saylor reduced it as a subgenus of Phyllophaga. The objective of the present study is to confirm the monophyly of Listrochelus by means of a phylogenetic analysis. A total of 132 species were analyzed; 31 species of them belong to Listrochelus, 76 are from other groups of Phyllophaga, and 25 species are from the outgroup. A morphological matrix with 281 characters was codified. A traditional search with 1000 iterations was performed in TNT. Branch support was investigated using the bootstrap method. Parsimony analysis resulted in ten equally parsimonious trees. The topology obtained in the strict consensus tree shows that the limits of Listrochelus are very clear (bootstrap 99%), supported by five synapomorphies and a combination of eight character states that are not exclusive to the group. Based on the hypothesis obtained, the restitution of the genus Listrochelus is proposed.