Juan Bolaños

Molecular phylogeny of enigmatic Caribbean spider crabs from the Mithrax–Mithraculus species complex (Brachyura: Majidae: Mithracinae): ecological diversity and a formal test of genera monophyly

STRI ; Marine biology ; Understanding and Sustaining a Biodiverse Planet ; forces of Change

LARVAL DEVELOPMENT OF PACHYCHELES SERRATUS (DECAPODA: ANOMURA: PORCELLANIDAE) UNDER LABORATORY CONDITIONS, WITH NOTES ON THE LARVAE OF THE GENUS

Abstract Larval stages and the megalopa of Pachycheles serratus are fully described and illustrated on the basis of laboratory-reared materials collected from Margarita Island, Venezuela. Complete development of P. serratus includes two zoeal stages and the megalopal (decapodid) stage, cultured at a water temperature of 25°C and salinity of 37‰. The first zoea lasts 5–6 days and the second lasts 8–10 days. A diagnostic character of the present species is the existence of a short mesial spine on the maxillular endopodite, unique among known zoeae of the genus Pachycheles. In addition, they can be distinguished from the first zoeae of P. laevidactylus and P. monilifer (western Atlantic congeners for which larval morphology is well-described) by size and ornamentation of the rostral spine, disposition of lateral spines on the abdominal somites, and setation of the maxilliped 3 in the second zoea. A comparative summary of zoeal morphology is provided for members of the genus Pachycheles.

ABBREVIATED LARVAL DEVELOPMENT OF THE PEA CRAB ORTHOTHERES BARBATUS (DECAPODA: BRACHYURA: PINNOTHERIDAE) DESCRIBED FROM LABORATORY-REARED MATERIAL, WITH NOTES ON LARVAL CHARACTERS OF THE PINNOTHERINAE

Abstract The pea crab Orthotheres barbatus is one of seven species of the family Pinnotheridae reported from Venezuelan marine waters. Larval life histories are not known for any species of the genus Orthotheres. Ten ovigerous females of O. barbatus were obtained from their host gastropod, Cittarium pica, at Los Roques Archipelago, Venezuela. Larvae of O. barbatus were reared in the laboratory from hatching to the first crab stage. This species exhibits abbreviated development in both the number of larval stages (two zoeal stages preceding a megalopa) and the duration of development (minimum of four days from hatching to first crab). The number of zoeal stages for pinnotherid species described to date ranges from 3 to 5, with only Tunicotheres moseri, Pinnotheres taylori, and Nepinnotheres pinnotheres known to also have only two zoeal stages. Morphology of the larval stages of O. barbatus is described, illustrated and compared to that previously described for larvae of the Pinnotherinae. Selected larval characters are proposed as typical larval features for this subfamily and are used to support separation of this group from the rest of Pinnotheridae.

A case of leg malformation in the Atlantic ghost crab Ocypode quadrata (Decapoda, Brachyura, Ocypodidae)

Morphological anomalies have been documented in several groups of arthropods, including fossils (Trilobites: Babcock, 1993; Lee et al., 2001; Chilopoda: Leśniewska, 2004; Mitić & Makarov, 2007; Insecta: Balazuc, 1948, 1969; Frank, 1981; Asiain & Márquez, 2009; and Crustacea: Dexter, 1954; Heerebout, 1969; Ros & Quiñones, 1981). In the Crustacea, putative processes or conditions causing malformations include injuries (e.g., on the carapace: Dexter, 1954; Riedl, 1975; Shelton et al., 1981); parasitic diseases, including viral infections (Primavera & Quinitio, 2000); somatic mutations or the erroneous result of morphogenetic processes (von Vaupel Klein & Koomen, 1993); contaminants (Weis et al., 1992); and exposure to extreme environmental conditions such as low temperatures (Pandourski & Evtimova, 2009). In decapods, malformations are commonly reported for the chelipeds, with lateral processes having been recorded in Carcinus maenas (Linnaeus, 1758) (cf. Heerebout, 1969); Erimacrus isenbeckii (Brandt, 1848), Chionoecetes opilio (Fabricius, 1788) (cf. Suzuki & Odawara, 1971); Procambarus clarkii (Girard, 1852) (cf. Nakatani et al., 1992); Paralithodes camtschaticus (Tilesius, 1885) (cf. Nickerson & Gray, 1963); Menippe mercenaria (Say, 1818) (cf. Ros & Quiñones, 1981) and Pachycheles serratus (Benedict, 1901) (cf. Lira et al., 2003), among others. Chelipeds are commonly used as weapons during agonistic interactions and to halt attacks by predators. Thus, injuries (subsequently producing malformations) might be expected in chelipeds with a greater frequency than in other body appendages like maxilipeds or walking legs. Furthermore, chelipeds are the

First record of Stenocionops spinosissimus (De Saussure, 1857) (Decapoda, Mithracidae) in Venezuelan waters

Majoids crabs are relatively well-know in shallow waters of Venezuela (Marcano & Bolaños, 2001), but under 60 m depth there are few records for the area. Stenocionops spinosissimus (De Saussure, 1857), has been reported from North Carolina, Florida, the Gulf of Mexico, Cuba, Haiti, Guadeloupe, Dominica, Colombia, Guyana, and Brazil (Rathbun, 1925; Powers, 1977; Takeda & Okutani, 1983; Melo, 1996; Cruz & Campos, 2003) in a depth range of 90-480 m. In an artisanal fishery on Margarita Island, three specimens of S. spinosissimus were collected at 190 m depth, representing the first record for Venezuela. Carapace length (CL) was measured from the rostral spines to the posterior end of the cephalotorax. The morphological characters agree adequately with the description of Rathbun (1925) and with the diagnosis of Melo (1996) for this species, and consequently no further description is presented. The material collected is deposited in the Museo Marino de Margarita and in the Laboratorio de Carcinología, Escuela de Ciencias Aplicadas del Mar, Universidad de Oriente, Margarita Island, Venezuela (GIC 0335).

Morphology of the larval stages of Pitho aculeata (Gibbes, 1850) (Crustacea, Brachyura, Majoidea) and its implications on the taxonomic position of the genus

ABSTRACT The larval development of Pitho aculeata is described and illustrated in detail. The characters described are used to discuss recent molecular phylogenetic findings suggesting that Pitho is a genus in Mithracidae sensu stricto. Based on species with known larval development, our results indicate that Pitho shares more similarities with mithracids than epialtids and therefore it should be included in the former family. Presently, there appear to be no diagnostic characteristics for the zoeal stages; however, for the megalopa the fused antennal articles 5 and 6 and the distinct number of setae on the abdominal somites 1–5 can be used to differentiate Pitho from other majoideans.

A case of malformation on the third maxilliped of Uca rapax (Smith, 1870) (Decapoda: Ocypodidae)

This paper evaluates the malformation in the left third maxilliped of a specimen of the fiddler crab Uca rapax from Venezuela. There are some hypotheses and the cause of the malformation remains unknown, but the results are indicative that is most likely due to errors in morphogenetic processes.

Primer hallazgo de Nibilia antilocapra (Stimpson, 1871) (Crustacea: Decapoda: Epialtidae) para Venezuela

Seven specimens of Nibilia antilocapra were collected in Margarita Island, Venezuela. This is the first record of N. antilocapra for Venezuela, and for the south Caribbean area. Nibilia antilocapra can be separated from other species of the family Epialtidae by the following features: wide postorbital tooth forming a cup, supraocular eave and postocular cup well separated, with a small tooth between them. Carapace pyriform, longer than wide, with several spines of different size on the surface. Chelipeds stouter than the walking leg, the formers diminish gradually in size. Four species of the subfamily Pisinae have been recorded for Venezuela marine waters.