Heteromysoides (Crustacea: Mysidacea: Heteromysini) from a submarine cave on Grand Cayman,the Caribbean Sea: descriptions of a new and a rare species

During a recent biological investigation of submarine caves of Grand Cayman, the Caribbean Sea, two species of Heteromysoides were collected. One species, referred to Heteromysoides spongicola B?cescu, 1968 Baˇcescu, M, 1968. Heteromysini nouveaux des eaux cubaines: trois espèces nouvelles de Heteromysis et Heteromysoides spongicola n. g. n. sp., Revue Roumaine de Biologie, Zoologie 13 (1968), pp. 221–237. [Google Scholar], is known only by the type specimens; therefore, this discovery marks the second record of occurrence and a new habitat record for the species. The other species is considered new and is described as H. stenoura, a 10th species of the genus. The new species closely resembles H. simplex Hanamura and Kase, 2001 Hanamura, Y, and Kase, T, 2001. A new species of Heteromysoides (Mysidacea: Mysidae) from submarine caves of Okinawa, southwestern Japan, with a key to the world species, Crustacean Research 30 (2001), pp. 65–71.[Crossref] , [Google Scholar], known from the submarine caves of Okinawa, north-western Pacific, in the possession of a spiniform process on the eyes and a simple termination to the third thoracic endopod. However, the new species can be readily distinguished from the Pacific congener by a distally narrow telson and a more developed cornea in the eyes.     

Polydora and related genera (Polychaeta: Spionidae) from the Grand Caribbean region

The study of previously unidentified material of Spionidae from the Grand Caribbean region resulted in the discovery of five new species in four genera: Boccardia salazari sp. nov., Dipolydora anatentaculata sp. nov., D. contoyensis sp. nov., Polydora quintanarooensis sp. nov. and Pseudopolydora floridensis sp. nov. Boccardia salazari is characterized by two types of major spine in chaetiger 5, one with expanded end bearing cusps without bristles, the other, simple, falcate; D. anatentaculata is characterized by an occipital antenna, and major spines simple, falcate, without subterminal protuberance; D. contoyensis is characterized by six pairs of branchiae on chaetigers 11–16, major spines with two large accessory teeth on concave and convex sides in chaetiger 5, and pygidium small, glandular, cuff‐shaped with dorsal notch; Polydora quintanarooensis is characterized by two eyes, modified spines of chaetiger 5 falcate, with a lateral tooth, and gizzard‐like structure present at segment 16, and Pseudopolydora floridensis is characterized by two types of major spines in chaetiger 5, first falcate, second pennoned, with both types arranged in U‐shaped, double row, a caruncle extending to chaetigers 6–7, and an occipital antenna. A key to all species of Boccardia, Dipolydora, Polydora and Pseudopolydora from the Grand Caribbean region is provided.     

The genus Coralaxius redefined,with the description of two new species (Crustacea: Decapoda: Axiidae)

The genus Coralaxius is rediagnosed, and the type species C. nodulosus (Meinert, 1877), the holotype of which was found to be identical with C. abelei Kensley and Gore, 1982, is redescribed. The two new species of Coralaxius are described, viz. C. galapagensis from the Galapagos Islands, and C. indopacificus from Fiji and the Comoro Islands. On the basis of carapace, gill and appendage characters, it is concluded that C. indopacificus is more primitive than the other two species. The genus is thought to have had a tethyan distribution, with the eastern Pacific representative being cut off from the western Atlantic form with the raising of the Isthmus of Panama.     

Cienfuegia gen. nov. (Xyalidae) and Pseudoterschellingia gen. nov. (Linhomoeidae), two new genera of free‐living marine nematodes from the Caribbean Sea

Two new genera of nematodes are described from the Caribbean Sea. Cienfuegia gen. nov. belongs to the Xyalidae based on the position of the anterior gonad constantly left of the intestine, cuticle clearly striated, second and third circle of anterior sensilla inserted at the same level and buccal cavity surrounded by pharynx. The new genus is differentiated from other genera by the buccal cavity divided in two chambers and by the four cephalic setae being longer than the six outer labial setae. Within the Xyalidae, Cienfuegia shows most affinities with the genera Daptonema and Theristus. Pseudoterschellingia gen. nov. is placed within the Linhomoeidae on the basis of the presence of anterior rounded amphidial fovea, unarmed narrow buccal cavity, distinctive cardia and presence of apophysis of gubernaculum. Pseudoterschellingia is closely related to the genera Terschellingia and Terschellingioides, but is differentiated by the crypto‐spiral amphidial fovea, and conical buccal cavity surrounded by pharyngeal tissue.     

Life history of the spider Selenops occultus Mello‐Leitão (Araneae,Selenopidae) from Brazil with notes on the natural history of the genus

Selenopids are extremely fast‐moving, dorsoventrally flattened spiders and are among the most secretive of animals. However, they can be locally abundant, providing an opportunity to examine their life and natural histories. Here we report life history data from Selenops occultus which were studied and collected monthly for over a year at an experimental farm of São Paulo State University in Botucatu, Brazil. We compare these data with what we have found in other Selenops species in the Caribbean region. Overall, S. occultus showed considerable seasonality. Males were most common in January and March, whereas females were more common in June and November. Significant differences between the numbers of males collected during the wet and dry seasons indicate that mating may be limited to the wet season. The Caribbean species share similar natural histories to S. occultus, such as little conflict in small areas and overlapping generations throughout the year.     

II.—Notes on some Australian Polyzoa

Forty-one species of 20 families of fishes were observed being cleaned at Bonaire by two species of decapod crustaceans and four species of fishes. Of 525 observations of fishes being cleaned (clients), over 60% involved species of the Serranidae, Scaridae and one species of Pomacentridae (Chromis multilineata). Gobies (Gobiosoma spp.) and Pederson's cleaner shrimp (Periclimenes pedersoni) were the most frequent cleaners of all three groups of clients. Only P. pedersoni performed a display that may have attracted clients. Cleaner species except Thalassoma bifasciatum cleaned the mouth and gills of clients, as well as the rest of the body. Clients approached cleaners, presented part of their body to the cleaner, opened their mouth or flared their gills, remained relatively motionless, and then twitched their tail and body and swam away. Unlike other clients, species of the Serranidae rarely assumed a vertical posture during cleaning. Chromis spp. and Clepticus parrai formed tight ball-like formations around cleaners. The behaviour of cleaner fishes and shrimp at Bonaire was more similar to that reported for eastern Pacific species than that of Labroides spp. of the Indo-Pacific area.     

Antipredator defence mechanism in the amphidromous shrimp Xiphocaris elongata (Decapoda: Xiphocarididae): rostrum length

Predators may affect prey through inducible defences that can alter prey phenotype. The shrimp Xiphocaris elongata exhibits a short rostrum (SR) in the absence of fish predators and a long rostrum (LR) in their presence. The long rostrum in X. elongata is inducible by the predatory fish Agonostomus monticola (mountain mullet). Our objective was to test whether the long rostrum is an effective antipredator defence against A. monticola in different stages of predator–prey interactions (i.e. choice, attacks, bites, rejections, handling time and survival). We conducted behavioural experiments in fish tanks in which we fed A. monticola simultaneously with (1) one LR shrimp and one SR shrimp, or (2) one LR shrimp and one shrimp which originally had a long rostrum but whose rostrum was cut (LR[S]). We scored the fish behaviours in terms of choice, unsuccessful attacks, bites, rejections and handling time. We also conducted mortality experiments in closed artificial pools in which we exposed (1) 10 LR and 10 SR shrimp or (2) 10 LR and 10 LR[S] shrimp to A. monticola, and quantified shrimp survival after 24 h. In the trials with LR and SR shrimp, A. monticola tended to attack SR shrimp first. LR shrimp were unsuccessfully attacked, bitten and rejected more than SR individuals. Handling time was higher for LR shrimp. The mortality experiments show higher survival of LR shrimp. In the trials with LR and LR[S] shrimp, A. monticola tended to attack LR[S] shrimp first. Unsuccessful attacks were similar for LR and LR[S]. There were more bites and rejections and longer handling time for LR shrimp. Survival was similar for LR and LR[S] shrimp in the mortality experiments. This study provides evidence in support of the hypothesis that the long rostrum in X. elongata is an effective antipredator defence against A. monticola by conferring benefits in most stages of the predator–prey interactions.