Daniel Roccatagliata

Diastylis fabrizioi, a new species and brief redescription of D. planifrons Calman, 1912 (Crustacea: Cumacea: Diastylidae) from South America

A new cumacean from the southwestern Atlantic, Diastylis fabrizioi, is fully described. This species is closely allied to Diastylis planifrons Calman, 1912, whose description is also completed. D. fabrizioi n. sp. can be easily distinguished from D. planifrons by having: (1) a wide pentagonal figure on the posterior part of the female carapace (a narrower pentagonal figure in D. planifrons), (2) a uniformly arched outline of the plateau when the carapace is seen from above (interrupted by two prominent blunt projections in D. planifrons), and (3) a telson with two divergent cuspidate setae distally (in close apposition in D. planifrons). Specimens housing nicothoid copepods inside their branchial chambers were observed in both species herein studied. One of these infested branchial chambers also contained two cryptoniscus larvae (Isopoda, Epicaridea).

Three New Species of the Genus Cyclaspis (Cumacea) From the South-West Atlantic With a Redescription of Cyclaspis Platymerus Zimmer, 1944

[Se describen tres nuevas especies del genero Cyclaspis Sars, 1865, colectadas en la plataforma continental de Brasil (C. jonesi, C. reticulata y C. micans) y Argentina (C. micans), y se redescribe a C. platymerus Zimmer, 1944. Se senala que, con excepcion de C. quadrituberculata Zimmer, 1907, las restantes especies americanas del mencionado genero presentan uropodos armados con fuertes espinas distales. En coincidencia con Zimmer (1943), se indica que la existencia dentro de este genero de especies con uropodos puntiagudos sin espinas distales y especies con uropodos truncados armados con fuertes espinas distales sugiere la presencia de por lo menos dos grupos naturales., Se describen tres nuevas especies del genero Cyclaspis Sars, 1865, colectadas en la plataforma continental de Brasil (C. jonesi, C. reticulata y C. micans) y Argentina (C. micans), y se redescribe a C. platymerus Zimmer, 1944. Se senala que, con excepcion de C. quadrituberculata Zimmer, 1907, las restantes especies americanas del mencionado genero presentan uropodos armados con fuertes espinas distales. En coincidencia con Zimmer (1943), se indica que la existencia dentro de este genero de especies con uropodos puntiagudos sin espinas distales y especies con uropodos truncados armados con fuertes espinas distales sugiere la presencia de por lo menos dos grupos naturales.]

CLA UDICUMA PLA TENSE ROCCATAGLIATA, 1981 (CUMACEA): A NEW REPRODUCTIVE PATTERN

An intertidal population of Claudicuma platense, a cumacean that inhabits the Rio de la Plata bottom, was sampled for 15 months. This species produces 3 generations per yearoverwintering, spring, and summer-instead of 2, as reported for other temperate shallow-water cumaceans. The spring and summer generations develop over a shorter period (about 2 and 3 months, respectively) than the overwintering generation (about 7 months). Lower abundances were observed in late winter (mean minimum abundance = 133 individuals m-2) when the population consisted mainly of adults, the survivors of the overwintering generation, whereas higher abundances occurred in early summer and early autumn (mean maximum abundances = 4,003 and 2,090 individuals m-2, respectively) when the population was composed primarily of mancas and juveniles. Claudicuma platense was also collected in the subtidal zone near the coast, where the temporal pattern of variations in abundance is apparently similar to that of the intertidal zone. Both the size of marsupial females and the fecundity decrease from overwintering, to spring, to summer generations. Each generation exhibits a linear, but different, female size-fecundity relationship. Hence, other factors, besides female size, influence the fecundity of C. platense.

On some Cyclaspis (Cumacea) from the South American Atlantic coast with the description of two new species

El presente trabajo es un aporte al conocimiento de las especies del genero Cyclaspis Sars, 1865 (Cumacea) del litoral atlantico sudamericano. Incluye la descripcion de dos nuevas especies, ambas localizadas sobre la plataforma continental: C. alba hallada en Uruguay y la Provincia de Buenos Aires, y C. variabilis hallada desde el Estado de Rio de Janeiro hasta la Provincia de Buenos Aires. Ademas se describen la hembre ovigera y el macho adulto de C. dolera Zimmer, 1944, con ejemplares obtenidos en una muestra de la plataforma continental del Estado de Rio de Janeiro; de esta manera se amplia la informacion referida a este especie, la cual fue erigida sobre la base de dos hembras inmaduras halladas en aguas someras centroamericanos. Por ultimo se redescribe el macho adulto y se describe las hembras adulta y subadulta de C. dentifrons Zimmer, 1944. Esta especie, citada originalmente para las cercanias de la Isla de Sao Sebastiao (Estado de Sao Paulo), fue hallada en una nueva localidad de la plataforma continental del mencionado Estado y en la plataforma continental del Estado de Rio de Janeiro.

First record of the hyperparasite Liriopsis pygmaea (Cryptoniscidae, Isopoda) from a rhizocephalan parasite of the false king crab Paralomis granulosa from the Beagle Channel (Argentina), with a redescription

The Cryptoniscidae are epicaridean isopod parasites or hyperparasites of other crustaceans. Liriopsis Schultze in Müller, 1859, one of the genera included in this family, now contains two nominal species: L. pygmaea (Rathke, 1843) and L. monophthalma (Fraisse, 1878). Both of these species infest rhizocephalan cirripeds, which are in turn parasites of hermit crabs. Among the false king crabs, Paralomis granulosa (Jacquinot, 1847), captured commercially in the Beagle Channel in 1996–1998, we found 31 specimens of the rhizocephalan Briarosaccus callosus Boschma, 1930 infested by one or more specimens of L. pygmaea. Neither L. pygmaea nor L. monophthalma has been reported previously for the southern seas. Although unidentified isopod hyperparasites have been found on B. callosus infesting other lithodids from Crozet Islands, South Georgia Island and Canadian Atlantic waters, this is the first time that one of these hyperparasites has been identified as a member of the genus Liriopsis. Since the differences between L. pygmaea and L. monophthalma remain obscure, the epicaridium and cryptoniscus larvae and three females stages of L. pygmaea are herein described from the material collected in the Beagle Channel.

Four Cyclaspis Species (Cumacea) From the South American Atlantic Coast

[Se describen tres nuevas especies - C. perelegans sp. n., C. striata sp. n., y C. oxyura sp. n. - y se redescribe C. pustulata Zimmer, 1943, todas pertenecientes al genero Cyclaspis Sars, 1865 y halladas frente a la costa brasilera. C. pustulata fue previamente localizada en la bahia de Chesapeake y en el estuario del Mississippi., Se describen tres nuevas especies - C. perelegans sp. n., C. striata sp. n., y C. oxyura sp. n. - y se redescribe C. pustulata Zimmer, 1943, todas pertenecientes al genero Cyclaspis Sars, 1865 y halladas frente a la costa brasilera. C. pustulata fue previamente localizada en la bahia de Chesapeake y en el estuario del Mississippi.]

On two Southwest Atlantic species of the genus Leptocuma Sars, 1873 (Crustacea: Cumacea)

Two species of the genus Leptocuma from the Southwest Atlantic have been studied. For L. kinbergii Sars, 1873 the adult male, and (very briefly) the marsupial female, are redescribed; for L. patagonicum n. sp. the adults of both sexes are described. In addition, a key to the American species of the genus Leptocuma is presented, the taxonomic position of some specimens previously assigned to L. kinbergii discussed, and the distributional range of L. kinbergii redefined.

Range Extension of Pseudidothea Miersii (Studer, 1884) (Isopoda, Valvifera) and New Evidence of Its Likely Commensal Relationship with a Sea Urchin

BRENDA L. DOTI1,3), DANIEL ROCCATAGLIATA1,4) and FABRIZIO SCARABINO2,5) 1) Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, UBA, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina 2) Dirección Nacional de Recursos Acuáticos, Constituyente 1497, C.C. 1612, C.P. 11200, Montevideo, Uruguay; and Museo Nacional de Historia Natural y Antropología, C.C. 399, C.P. 11000, Montevideo, Uruguay

On two paramunnid species from the Beagle Channel, Argentina (Crustacea: Isopoda: Asellota)

ABSTRACT Austrosignum fuegiae, a new species, is fully described on the basis of specimens collected in the shallow waters of the Beagle Channel. The genus Austrosignum Hodgson, 1910 is in need of revision, and the inclusion of A. fuegiae in this genus should be considered provisional. Austrosignum fuegiae is most similar to A. dentatum Winkler, 1994, which was previously known from the Magellan Strait and is herein recorded for the Beagle Channel for the first time. These two species have a head with bilobed frontal margin, short eyestalks, and mandibles with palps, a group of characters that is not shared by the type species of the genus, A. grande Hodgson, 1910.

On Two Species of Diastylis (Cumacea) from the Southwestern Atlantic: D. sexpectinata n. sp. and D. hammoniae Zimmer, 1902

Abstract Diastylis sexpectinata, a new species of cumacean that extends from São Paulo State (Brazil) to northern Patagonia (Argentina), is herein fully described and illustrated. This species can be easily distinguished from the other members of the genus by the following combination of characters: 1) carapace with a pair of anterolateral horns and six longitudinal rows of conical teeth (middle and uppermost rows poorly developed or absent in the adult male), 2) third and fourth pereiopods of the female without rudimentary exopods, and 3) uropod endopod consisting of two articles, the proximal one in the female with 3-4 teeth on outer margin. The description of the female of Diastylis hammoniae is completed and the adult male described for the first time based on its type material and additional specimens herein reported. The type species of Leptostylis (?) mancoides was also re-examined and its synonymy with Diastylis hammoniae is proposed. The synonymy of D. hammoniae with Diastylis manca is also strongly suspected, but until additional specimens become available D. manca should be treated as “species inquirenda.” An identification key to the species of the genus Diastylis from Argentina and Uruguay is given.