Review of the Leptogenys unistimulosa species group (Hymenoptera: Formicidae) with the description of a new Amazonian species

ABSTRACT Leptogenys elzasoares new species, is described from workers and a male collected near Manaus in the Brazilian Amazon. The worker is recognizable by the presence of 12 chaetae (stout setae) on the clypeal median lobe, the straight mandible, and its bicolored body; the head and mesosoma are black while the gaster is brightly ferruginous. For the first time, the males of L. bohlsi Emery, 1896, L. unistimulosa Roger, 1863, and L. parensis Lattke, 2011 are described. A new key to the males of the unistimulosa species group is provided, and the key to workers of Lattke (2011) is updated to include the new species. Finally, we also report new records of L. parensis from French Guiana, expanding the known distribution by over 780 km northwest.

A tardigrade in Dominican amber.

Tardigrades are a diverse group of charismatic microscopic invertebrates that are best known for their ability to survive extreme conditions. Despite their long evolutionary history and global distribution in both aquatic and terrestrial environments, the tardigrade fossil record is exceedingly sparse. Molecular clocks estimate that tardigrades diverged from other panarthropod lineages before the Cambrian, but only two definitive crown-group representatives have been described to date, both from Cretaceous fossil deposits in North America. Here, we report a third fossil tardigrade from Miocene age Dominican amber. Paradoryphoribius chronocaribbeus gen. et sp. nov. is the first unambiguous fossil representative of the diverse superfamily Isohypsibioidea, as well as the first tardigrade fossil described from the Cenozoic. We propose that the patchy tardigrade fossil record can be explained by the preferential preservation of these microinvertebrates as amber inclusions, coupled with the scarcity of fossiliferous amber deposits before the Cretaceous.

A review of the Nearctic Odontomachus (Hymenoptera: Formicidae: Ponerinae) with a treatment of the males.

The ant genus Odontomachus Latreille in the United States is reviewed. Six species are treated: O. brunneus (Patton), O. clarus Roger, O. desertorum Wheeler stat. nov., O. relictus Deyrup and Cover, O. ruginodis M.R. Smith, and O. haematodus (Linnaeus), a new record for North America. The spread of O. haematodus is documented, and its identity is clarified. The genus is diagnosed for species in the Nearctic region for all castes, and worker- and male-based keys are presented. The workers and males of all six species are described and figured, including the first male descriptions for O. haematodus and O. desertorum. This represents the first study of species-level variation in Odontomachus male genitalia, and one of the first of such studies of the Ponerinae for any biogeographic region. A discussion of the utility of the male sex for Odontomachus taxonomy is provided.

Central American ants of the genus Megalomyrmex Forel (Hymenoptera: Formicidae): six new species and keys to workers and males.

Megalomyrmex Forel is a distinctive lineage of Neotropical ants, some of which are specialized parasites or predators of the fungus-growing ants Attini. Here we review and key the Central American fauna. Six new species are described from both female castes: M. brandaoi sp. n., M. fungiraptor sp. n., M. longinoi sp. n., M. milenae sp. n., M. megadrifti sp. n. and M. osadrifti sp. n. A worker-based key to all Central American species is presented, and all species are illustrated. Megalomyrmex drifti Kempf is redescribed and the first descriptions of queens for M. miri Brandão and M. foreli Emery are provided. New biological information, several new geographic records, and a discussion of the species-group schema of Brandão (1990) are presented. The male sex of Megalomyrmex is diagnosed at the genus-level and keyed to species for the Central American fauna, where known. The male of each species treated in the key is diagnosed, described, or redescribed. Males are known for fourteen out of twenty total Central American Megalomyrmex species. A distinct but unassociated male is described and keyed (M. male 01). The males of M. miri Brandão and M. wettereri Brandão are described for the first time, and the distinctness of these two species is confirmed. One potential synapomorphy of Megalomyrmex present in males and workers is the presence of a carina which posteriorly delimits the basalmost region of the petiolar dorsum. 

New species of Central American Rhopalothrix Mayr, 1870 (Hymenoptera, Formicidae).

The ant genus Rhopalothrix is a rare inhabitant of wet forest leaf litter and soil. We propose a monophyletic R. isthmica clade that is restricted to the Neotropics, contains most of the species in the genus, and has its center of abundance and diversity in Central America. Thirteen species are recognized in the R. isthmica clade, of which eight are described as new and three are redescribed. A key to species in the R. isthmica clade is provided, and the following eight new species are described: R. andersoni Longino & Boudinot, sp. nov., R. apertor Longino & Boudinot, sp. nov., R. atitlanica Longino & Boudinot, sp. nov., R. megisthmica Longino & Boudinot, sp. nov., R. nubilosa Longino & Boudinot, sp. nov., R. subspatulata Longino & Boudinot, sp. nov., R. therion Longino & Boudinot, sp. nov., and R. triumphalis Longino & Boudinot, sp. nov.. Queens are newly associated with workers for three Central American species. New synonymy is proposed for Rhopalothrix plaumanni Brown & Kempf, 1960 = R. acutipilis Kempf, 1962, syn. nov.