Seasonal distribution of a relatively rare and a relatively common species of Thecomyia at Belém, Pará, Brazil (Diptera: Sciomyzidae)

O gênero neotropical Thecomyia (Sciomyzidae) consiste de quatro espécies descritas e onze ainda não descritas (Steyskal & Knutson em preparação), sendo a maioria não muito comum. As espécies são muito próximas e grande número delas somente pode ser separado com base na genitália do macho. Somente é conhecida a biologia e uma espécie, T. limbata (Wiedermann), que, preferentemente, preda moluscos aquáticos (Abercrombie & Berg, 1975). A análise de registros de coletas de espécies relativamente raras e relativamente comuns de Thecomyia (172 especimens do Museu Goeldi coletados em Mocambo, Belém, Pará, Brasil) proporcionam informações sobre a distribuição sazonal de espécies tropicais e sua relativa abundância. Deste material 160 especimens pertencem à T. longicornis Perty e 12 à Thecomyia sp. n. A primeira foi registrada durante todos os meses do ano, mas a espécie nova somente durante junho e dezembro, sugerindo esta última uma população de adultos anual bimodal.

Distributional patterns of the Neotropical genus Thecomyia Perty (Diptera, Sciomyzidae) and phylogenetic support

Distributional patterns of the Neotropical genus Thecomyia Perty (Diptera, Sciomyzidae) and phylogenetic support. The distributional pattern of the genus Thecomyia Perty, 1833 was defined using panbiogeographic tools, and analyzed based on the phylogeny of the group. This study sought to establish biogeographical homologies in the Neotropical region between different species of the genus, based on their distribution pattern and later corroboration through its phylogeny. Eight individual tracks and 16 generalized tracks were identified, established along nearly the entire swath of the Neotropics. Individual tracks are the basic units of a panbiogeographic study, and correspond to the hypothesis of minimum distribution of the organisms involved. The generalized tracks, obtained from the spatial congruence between two or more individual tracks, are important in the identification of smaller areas of endemism. Thus, we found evidence from the generalized tracks in support of previous classification for the Neotropical region. The Amazon domain is indicated as an area of outstanding importance in the diversification of the group, by the confluence of generalized tracks and biogeographic nodes in the region. Most of the generalized tracks and biogeographical nodes were congruent with the phylogenetic hypothesis of the genus, indicating support of the primary biogeographical homologies originally defined by the track analysis.

Monographs of the Diptera of North America /

Part 2 by H. Loew, edited by R. Osten Sacken (dated Jan. 1864); pt. 3 by H. Loew (dated Dec. 1873); pt. 4 by R. Osten Sacken (dated Jan. 1869)