Characterization and distribution of Teredinidae assemblage in an estuary in Ceará, Brazil's Northeast.

Teredinids are bivalves mollusks considered the most abundant of invertebrates group of marine wood borers performing an important role in the mangrove environment. This study aimed to characterize the Teredinidae species from the Acaraú River estuary in Ceará and analyse the relationship between the mangrove plant structure and the distribution of Teredinidae, according to gradients estuaries: vertical (flooding) and horizontal (salinity). The collection of mangrove logs with Teredinidae happened in three places within the estuary (inner, median, and upper); in each area, three transects were traced in which three plots were lined off, and a total of 40 logs were collected. Teredinidae species were found and identified: Nausitora fusticula; Neoteredo reynei; Teredo turnerae; Teredo cf. bartschi; Bankia bipennata; Bankia gouldi; Lirodus massa and Lyrodus cf. bipartitus. The Lyrodus cf. bipartitus, Bankia gouldi, and Teredo cf. bartschi species were registered for the first time in Ceará. The distribution and species richness of Teredinidae were directly related to the vertical gradient (flooding) and heterogeneity of the mangrove forest habitat. The data presented here are essential for comprehending the mechanisms responsible for the distribution patterns of the Teredinidae species in the mangrove, contributing to biodiversity conservation in Ceará coastal zones.

Reproductive cycle and embryonic development of the gastropod Melampus coffeus (Linnaeus, 1758) (Ellobiidae) in the Brazilian Northeast.

Melampus coffeus belongs to a primitive group of pulmonate mollusks found mainly in the upper levels of the marine intertidal zone. They are common in the neotropical mangroves. Little is known about the biology of this species, particularly about its reproduction. The aim of this study was to 1) characterize the morphology and histology of M. coffeus' gonad; 2) describe the main gametogenesis events and link them to a range of maturity stages; 3) chronologically evaluate the frequency of the different maturity stages and their relation to environmental factors such as water, air and sediment temperatures, relative humidity, salinity and rainfall; and 4) characterize M. coffeus' spawning, eggs and newly hatched veliger larvae. Samples were collected monthly between February, 2007 and January, 2009 from the mangroves of Praia de Arpoeiras, Acaraú County, State of Ceará, northeastern Brazil. The characterization of the gonad development stages was carried out using routine histological techniques. The results of this study show that Melampus coffeus is a simultaneous hermaphrodite. The follicles have masculine and feminine elements, interleaved within the gonad. M. coffeus presents a well-defined synchronous reproductive cycle, showing successive maturation, release and resting periods. The average diameter of the oocytes was negatively correlated with salinity and positively correlated with rainfall. The results show that no reproductive activity occurs during periods of drought. After the dry season, the increasing rainfall levels and reduced salinity lead to the appearance of very dense populations, predominantly composed of small individuals.

Gonad characterization and reproductive cycle of Collisella subrugosa (Orbigny, 1846) (Gastropoda: Acmaeidae) in the Northeastern Brazil

Gonad characteristics and reproductive cycle in the acmaeid Collisella subrugosa from Northeastern Brazil were investigated. The individuals were collected monthly from February 1993 to April 1994 at Farol do Mucuripe Beach, Fortaleza, Ceará, Brazil. There is no external characteristic on the shell and the soft body structures except the gonad that allows sex differenciation. The gonad of limpet Collisella subrugosa showned four stages (1) "partially ripe", (2) "ripe", (3) "partially spawned" and (4) "spawned", stages. The reproductive cycle is continous, with the maturation and spawning running parallelly in this population. The temperature was constant during the study period and it did not seem to be important to induce the spawning. The salinity had a weak negative correlation with the spawn process

Gonad characterization and reproductive cycle of Collisella subrugosa (Orbigny, 1846) (Gastropoda: Acmaeidae) in the northeastern Brazil.

Gonad characteristics and reproductive cycle in the acmaeid Collisella subrugosa from Northeastern Brazil were investigated. The individuals were collected monthly from February 1993 to April 1994 at Farol do Mucuripe Beach, Fortaleza, Ceará, Brazil. There is no external characteristic on the shell and the soft body structures except the gonad that allows sex differentiation. The gonad of limpet Collisella subrugosa shown four stages (1) "partially ripe", (2) "ripe", (3) "partially spawned" and (4) "spawned", stages. The reproductive cycle is continuous, with the maturation and spawning running parallell in this population. The temperature was constant during the study period and it did not seem to be important to induce the spawning. The salinity had a weak negative correlation with the spawn process.