Estrutura populacional de Armases angustipes (Dana) (Decapoda, Brachyura, Grapsidae) na Ilha do Farol, Matinhos, Paraná

Abstract

ABSTRACT. Population structure of Armases anguslipes (Dana) (Decapoda, Brachyura, Grapsidae) from Farol Island, Matinhos, Paraná. Annual fluctuation of densities and population structure ofArmases angustipes (Dana, 1852) from a rocky shore at Farol Island, Matinhos, Paraná, Brazil (25°51 'S and 48°32'W) were studied. The population structure was treated in the following aspects: sexual proportion, dial intensity of activities, size composition and its fluctuation, and general condition of the crabs. The collections were made monthly, from January to December 1991. The samples were obtained handly, in the morning and at night, at the supratidal zone during low tides. There were caught 1,139 crabs, among which 34 were juveniles, 544 males, 555 females and 4 ovigerous females. Population density was highest in April (19.56 ind.m· 2 ) and in October (23 .86 ind.m· 2 ). The sexual proportion was 1:1 in eleven months. Although the mal e crabs were more abundanl than the females in May, there was not any statistical signiticant difference between the sexes. The activity of the population is intenser at night than at moming for both sexes. The recruilment of juveniles occurs mainly in March, April and July. The condition factor in females is related to thê reproductive period. The population can migrate to lhe terrestrial habitat near the supratidal zone. KEY WORDS. Armases angustipes, crabs, population structure, rocky shore, Matinhos, Brazil Os representantes marinhos de Grapsidae ocupam, caracteristicamente, a estreita área entre o ambiente terrestre e o aquático, onde são elementos importantes e conspícuos da fauna carcinológica (HARTNOLL 1965).O gênero Sesarma foi estabelecido em \817 por Say, com Ocypode reticl/-latus como espécie-tipo, e a inclusão de aproximadamente 130 espécies das regiões temperada e tropical resultou em confusão sistemática (TESCH 1917;ABELE 1992). O último autor revisando o gênero Sesarma, criou um novo gênero denominado Armases, para o qual alocou 12 espécies anteriormente pertencentes a Sesarma.As espécies americanas de Sesarma e Armases ocorrem em uma ampla variedade de habitats desde água doce de cavernas, rios e ribeirões, manguezais, marismas e a zona intertidal alta. Nenhuma espécie poderia ser classificada como tipicamente marinha subtidal, já que todas são ativas pelo menos algum tempo na terra (ABELE \992).

Larval Morphology of the Sesarmid Crab Armases Angustipes Dana, 1852 (Decapoda, Brachyura, Grapsoidea)

“…A comparison of the previous description of the larval development of A. angustipes (Kowalczuk, 1994) and the present results is given in Table 2. The setation of the carapace was not described by Kowalczuk (1994) and therefore this character cannot be compared here; a detailed description is given above (see text and figures).…”

“…Another important difference was observed on the inner surface of the scaphognathite of the megalopal maxilla. In the present study, two setae were observed on the anterior and one seta on the posterior area; the latter was not described by Kowalczuk (1994). This is significant insofar as the setation (2 + 1) is a typical character which allows one to distinguish sesarmid megalopae from all other grapsoid megalopae (Cuesta, 1999).…”

“…The setation of the carapace was not described by Kowalczuk (1994) and therefore this character cannot be compared here; a detailed description is given above (see text and figures). Hence, this character is not included in Table 2.…”

“…Within this genus, larval morphology has been described for the following species: A. cinereum (Bosc, 1802) by Costlow and Bookhout (1960) and Schubart and Cuesta (1998);A. ricordi (H. Milne Edwards, 1853) and A. rubripes (Rathbun, 1897) by Díaz and Ewald (1968) and Schubart and Cuesta (1998); A. angustipes Dana, 1852, by Kowalczuk (1994and A. miersii (Rathbun, 1897) by Cuesta et al (1999). According to Niem (1996) and Schubart et al (2000), the monotypic Aratus pisonii (H. Milne Edwards, 1837) is also closely related to Armases and therefore is included in our morphological comparison (see Warner, 1968;Fransozo et al, 1998).…”

Larvae and first‐stage juveniles of the American genusArmasesAbele, 1992 (Brachyura: Sesarmidae): a morphological description of two complete developments and one first zoeal stage

“…angustipes (Dana, 1852) by Kowalczuk (1994) and Cuesta and Anger (2001);A. miersii (Rathbun, 1897) by Zimmermann-Ruf (1997) and Cuesta et al (1999), and most recently A. benedicti (Rathbun, 1897) by Lima and Abrunhosa (2006).…”