Carlos Henrique Soares Caetano

Imposex in Olivancillaria vesica vesica (Gmelin) (Gastropoda, Olividae) from a Southeastern Brazilian sandy beach

Imposex, the development of male sex organs on the female, is registered and described for Olivancillaria vesica vesica (Gmelin, 1791) at Restinga da Marambaia beach, Rio de Janeiro state, Brazil.

Biphallia in imposexed females of marine gastropods: new record for Nassarius vibex from Brazil

Imposex is an endocrine disruption syndrome, in which females of marine gastropods develop sexual characteristics of males (penis and/or vas deferens) (Smith, 1971). This syndrome is caused by tributyltin (TBT) or triphenyltin (TPT), toxic organotin compounds found in naval paints used as antifouling system in boats and artificial structures (Gibbs and Bryan, 1987 and Axiak et al., 2003). Quantification of TBT by chemical analysis in water or sediment is very onerous, therefore imposex as a tool to detect contamination by organotin compounds is often used. Five genus of marine gastropods in the Brazilian littoral have already been studied and the occurrence of imposex was related to either mild or severe contamination by TBT (Fernandez et al., 2005 and Limaverde et al., 2007). Nassarius (Mollusca: Gastropoda) is a ubiquitous genus that has been proposed as a bioindicator of TBT pollution (Marshall and Rajkumar, 2003). Here, we report the novel occurrence of imposex in Nassarius vibex (Say) in south Brazil and the biphallia in imposexed females of this species. Specimens of N. vibex were collected at Flexeira beach (22° 56’ S and 43° 53’ W), Itacuruçá Island, Rio de Janeiro state, Brazil, in the intertidal zone at spring low tide in September 2007. Two fixed transects (500 m apart) were established from the lower limit of the swash zone to 10 m above the drift line (supralittoral). Next, ten equally spaced sampling strata parallel to the water line were marked according to a systematic design with stratification. At each stratum, five replicate quadrats of 0.04 m (systematically allocated 3 m apart) were taken to a depth of 25 cm and sieved through 0.7 mm mesh. This beach is exposed to effects of the yachting activities of Itacuruçá Yacht Club (distant 1.1 km) and Sepetiba Harbor (distant 7.3 km), which constituted potential sources of TBT pollution. In the laboratory, shell length (Figure 1a and b) was measured with a vernier caliper, then cracked and opened in a vice, and the individuals of N. vibex removed and examined for sex determination. Individuals having seminal vesicle were identified as males while others with seminal vesicle absent, as females. Females with male sex organs (e.g. penis) were identified as imposexed females. Penis length of males and imposexed females was measured under a stereoscopic microscope and the Relative Penis Length Index (RPLI) and Relative Penis Size Index (RPSI) were calculated according to Gibbs and Bryan (1987). A total of 155 individuals were collected, with 86 males (55.48%, Figure 1c) and 69 females (44.52%). All the females examined present the occurrence of imposex (Figure 1d). Two imposexed females presented biphallia (i.e. double penis, see Figure 1e and f). These

Population Biology and Secondary Production of Excirolana braziliensis (Isopoda: Cirolanidae) in Two Sandy Beaches of Southeastern Brazil

Abstract The population dynamics and secondary production of the cirolanid isopod Excirolana braziliensis are compared between two distinct sandy beaches. Monthly sampling from June 1998 through July 2000 was carried out at Grumari (a reflective beach with coarse sand and steeper slope) and Restinga da Marambaia (an intermediate beach with fine sand and moderate slope), both located in Rio de Janeiro State (23° S), southeastern Brazil. Sampling was conducted according to a systematic design in which two transects (fixed 500 meters apart) were established, each with 10 equally spaced sampling strata. From each stratum, five replicates (0.04 square meters) were taken. Highest population abundances were observed in spring and summer on both beaches. The beaches differed significantly in physical parameters and the characteristics of their inhabitant populations: (1) Grumari Beach had a steeper slope, coarse sands, and a short swash period; (2) the abundance of total population, fecundity at length, and egg production potential were higher at Restinga da Marambaia; and (3) individual growth of males was higher at Grumari. Mean length at sexual maturity (L50%), mortality, growth of females, secondary production, and mean annual biomass did not show significant differences between beaches. Variations in population parameters of E. braziliensis might be regulated by phenotypic adjustment to local conditions, optimizing fitness, and especially enabling species to adapt to different physical conditions.

Brazilian species of Gadila (Mollusca: Scaphopoda: Gadilidae): rediscovery of Gadila elongata comb. nov. and shell morphometrics

Gadila elongata comb. nov. was described in 1920 from the northern Gulf of Mexico. Until recently, it was only known from the type locality. Herein we present the first record of G. elongata from Brazil (Northeast coast, Ceara state, collected at 177 m) and a morphometrics analysis of the Brazilian species of Gadila. A multivariate Discriminant Function Analysis, based on nine shell morphometric variables (length, maximum diameter, length to maximum diameter ratio, distance of point of maximum diameter from anterior aperture, maximum curvature, anterior aperture height to anterior aperture width ratio, apical aperture height, apical aperture width and apical aperture height to apical aperture width ratio) enabled the distinction between all species studied. Comparisons of shell morphometrics show that length and length to maximum diameter ratio are the most important variables in the differentiation of Gadila species.

A commented list of Scaphopoda (Mollusca) found along the Brazilian coast, with two new synonymies in the genus Gadila Gray, 1847

This review aims to present an updated checklist of scaphopods, based mainly on literature database. There is a total of 40 species (six families) for Brazil, including information about the distribution and bathymetric range of each taxon. We propose two synonyms with the aid of morphometry of the shell, for the genus Gadila: G. longa as junior synonym of G. elongata and G. robusta as junior synonym of G. pandionis.

Larval and early post-larval shell of three deep-sea Scaphopoda (Mollusca) from the southwest Atlantic

ABSTRACT The larval shells of Antalis circumcincta (Watson, 1879) (order Dentaliida), Pertusiconcha callithrix (Dall, 1889) (order Gadilida) and of an undetermined species of uncertain systematic position are described. The material studied comprises mainly samples from deep waters, collected by expeditions along the southeast coast of Brazil. The larval shell of the three taxa matches other types previously described in the literature. Antalis circumcincta and P. callithrix have four regions (protoconch A, protoconch B, teleoconch A, teleoconch B), but differ in dimensions and sculpture from each other, while the undetermined species has three regions (protoconch A, protoconch B, teleoconch B). A morphometric approach combined with a discriminant analysis also indicates that the three taxa are significantly distinct. This study confirms patterns of larval shells at the taxonomic rank of orders but other supraspecific patterns remain uncertain.

mtDNA analysis of Mytilopsis (Bivalvia, Dreissenidae) invasion in Brazil reveals the existence of two species

The genus Mytilopsis includes some of the most invasive estuarine bivalves in the world, and M. leucophaeata (native to the Gulf of Mexico) and M. sallei (indigenous in the Caribbean Sea) are the most often reported species. Molecular investigations of the COI gene in invasive populations of M. leucophaeata in Europe found only one haplotype, whereas the invasive M. sallei in Asia had high haplotype diversity. The present study investigated COI variability of invasive populations previously identified as M. leucophaeata in Brazil, located at the cities of Recife and Rio de Janeiro. Our genetic analysis revealed that the record of M. leucophaeata from Recife appears erroneous; this population forms a clade adjacent to but genetically separated from the Asian M. cf. sallei. Similarly, samples from Rio de Janeiro clustered close to but not within European/North American sequences of M. leucophaeata. The Automatic Barcode Gap Discovery test suggested the existence of three species: M. leucophaeata, M. cf. sallei (Asia), and M. cf. sallei (Recife), which merit confirmation with nuclear DNA sequences. The discovery of two lineages of Mytilopsis in Brazil augments concerns about their expansion.