A new Brazilian species of the cricket genus Megalogryllus Chopard (Orthoptera: Gryllidae)

Abstract

In 1929 Chopard published the description of a new genus and species of cricket (Megalogryllus molinai), giving the collecting locality as "Types: Brésil: Manaos 1 Guyane anglaise". Chopard's paper shows the dorsal view of a male of the species but illustrations on the phallic structure were not included. In 1964, Randell published a study on the phallic structure of several species of Gryllinae including his drawings (fig. 10a, b, c) as well as a description of the phallic sclerites (p. 1577-78) of the male type of M. molinai. Collecting in a "cerrado" vegetation near Corumbatai town on November 11 th 1985, a female of a not identified species of cricket was obtained (Fig. 1a). Since then, yearly collections in this locality, which measures about 300 ha, failed to obtain more specimens. More than a decade later, December 1996, while collecting insects in the same locality, a very loud and continuous calling cricket song was heard. With the help of a directional microphone three males of a large cricket were captured. Cytologycal analysis of this specimens were unsuccessful because the meiotic process was already completed and only spermatozoa were observed. When dissection and drawings of the phallic structures were performed, a comparison with Randell´s drawings showed that the Corumbatai specimens belonged to Chopard´s genus Megalogryllus. The mention of the last author about the shape and size of the ovipositor proves that the single female collected in 1986 belongs to the same species than the three males collected a decade later (Fig. 1a). A careful comparison of Randell´s and our drawings on the male genitalia shows however some differences that justify to consider the Corumbatai specimens as a new species of Megalogryllus. Type material is deposited in the collection of the Museu de Zoologia da Universidade de São Paulo (MZUSP) and in the collection of the Universidade Estadual Paulista (UNESP), campus of Rio Claro, SP. Megalogryllus clamosus n. sp. Diagnosis. The phallic structure of M. clamosus is quite similar to that drawn by Randell in his fig. 10a, b, c of M. molinai. The differences are: a) In M. clamosus a rami plate does not exist but a slightly more dense membrane connecting the PECS to the DECS. b) Randell´s ectoparameres and mesal lobe are parts (right and left) of a single sclerite that in Randell´s interpretation are divided at each side into ectoparameres and mesal lobe. c) The structure of the PENS which is connected by fibrilar tissue (as expected) with DENS is not clearly defined in his drawings. Apart from differences in interpretations, Randell´s and the drawing of this paper are quite similar but clearly different in details mainly in the structure that are here named DENS. Male (Fig. 1a,Table 1). Color uniformly brown, lighter in the abdominal region. Tegmen as in Fig. 2. Fore tibia armed with SYSTEMATICS, MORPHOLOGY AND PHYSIOLOGY Nova Espécie de Grilo do Gênero Megalogryllus Chopard (Orthoptera: Gryllidae) RESUMO-Megalogryllus clamosus, uma nova espécie de grilo do estado de São Paulo, é descrita. As fotografias do holótipo (macho) e do parátipo (fêmea) são apresentadas, assim como o desenho do tégmen direito do macho e a estrutura fálica. As fotografias da pars stridens para mostrar a estrutura dos dentes e o sonograma do canto de chamado do macho são também apresentados. ABSTRACT-Megalogryllus clamosus a new species of cricket from the São Paulo State (Brazil) is described. Photographs of the holotype (male) and of the paratype (female) are provided, as well as a drawing of the structure of the right tegmen of the male and of the phallic sclerite structure. Photographs of the pars stridens teeth and sonogram of the male calling song are also provided.