Biology and life cycle of Tmetonyx similis (G. O. Sars, 1891) (Amphipoda,Lysianassidae), a scavenging amphipod from the continental slope of the Mediterranean

The present study focused on the biology and life cycle of Tmetonyx similis, a scavenging amphipod inhabiting the continental slope of the north‐western Mediterranean. All the categories of individuals were observed in the samples. The emergence of offspring occurs in successive cohorts. The lifespan of the females is longer than that of the males, but the sex ratio is strongly in favour of the males. The fecundity was found to be lower than that of the other female crustaceans present in these samples. The growth pattern was modelled. A strong correlation was observed between the length and the weight of the animals collected. Several hypotheses are proposed to explain a sex ratio in favour of males. This result may be explained by a migratory process of the females of T. similis. A comparison of the reproduction strategy is given for the three main scavenger crustacean species (amphipods and isopod) collected in this area.     

Oostegite development during the sexual maturation of females of Tmetonyx similis (G. O. Sars, 1891) (Amphipoda,Lysianassidae)

The development of the oostegites was studied in the females of Tmetonyx similis (Crustacea, Amphipoda) during the period of sexual maturation. The process is complex and involves a series of variably long sequences. These sequences may constitute a means of adjusting the animals' sexual maturation to environmental conditions in order to increase their reproductive efficiency. The age and lifespan given by most authors working on amphipod species have probably been underestimated and should be regarded as minimum data. The physiological significance of the development of the oostegites is probably more complex than has generally been thought to be the case up to now.     

The life cycle of Diploproctodaeum arothroni Bray and Nahhas, 1998 (Digenea: Lepocreadiidae), with a comment on the parasitic castration of its molluscan intermediate host

Diploproctodaeum arothroni Bray and Nahhas, 1998 Bray, R. A. and Nahhas, F. M. 1998. Diploproctodaeum arothroni n. sp. (Digenea: Lepocreadiidae) from the pufferfish Arthron hispidus (Tetraodontidae) from Suva, Fiji, with a revised key to the species of the genus.. Systematic Parasitology, 40: 55–59. [Crossref] , [Google Scholar] (Digenea: Lepocreadiidae) was found in the intestine of its type‐host, Arothron hispidus, a tetraodontid fish permanently resident in a lagoon within the mangrove swamps on the Egyptian coast of the Gulf of Aqaba. Larval forms of this trematode (sporocysts, rediae, and cercariae) were found in the gonads and digestive gland of Crassostrea cuccullata (Ostreidae), a common oyster in the same lagoon. So, the life cycle of D. arothroni is elucidated under natural conditions; eggs are directly ingested by the oyster; mother sporocysts and rediae reach their maturity 3–5 and 9–11 weeks after infection; rediae contain 18–25 developing cercariae; fully mature cercariae are trichocercous, without penetration glands, emerge from the oyster during the night 14–15 weeks after infection, their existence in seawater being very brief and transitory, and rapidly encyst on aquatic vegetation or other surfaces (there is no second intermediate host); encysted metacercaria are not progenetic; 4‐day‐old metacercariae encysted on filamentous algae fed to A. hispidus developed into fully mature worms 8–9 weeks after infection. This cycle is completed in about 24 weeks and has its own characteristics, which differentiate it from the other known lepocreadiid life cycles. All of the developmental stages are figured and described. Parasitic castration in the females of C. cuccullata caused by the parasite was studied histologically and is described and discussed.     

Marphysa cinari,a new species of Eunicidae (Polychaeta) from the coasts of Turkey (eastern Mediterranean) and re-descriptions of Marphysa kinbergi McIntosh, 1910 and Marphysa disjuncta Hartman, 1961

The present study describes a new polychaete species belonging to the family Eunicidae, Marphysa cinari sp. nov., collected from the Sea of Marmara and the Aegean Sea (eastern Mediterranean), and re-describes Marphysa disjuncta Hartman, 1961 and Marphysa kinbergi McIntosh, 1910. The new species is mainly characterized by having unidentate subacicular hooks with a terminal hood and compound falciger chaetae on posterior parapodia. The shape of unidentate hooks of M. cinari is a very important character for distinguishing this species from other species. Atlantic species M. kinbergi and Pacific species M. disjuncta are very close species and the present paper deals with the differences and similarities between them and the new taxon.

http://zoobank.org/urn:lsid:zoobank.org:pub:E8503032-81D3-4B4D-AAA0-9164E05E613F