RESUMEN
Urobatis jamaicensis is a coastal batoid species affected by habitat loss and small-scale exploitation from fisheries and the aquarium trade, yet the life-history information available is limited. This is the first study to assess the vertebral centra from 195 stingrays to estimate age and growth patterns, and compare them with the biannual reproductive pattern previously reported for this species. Age-at-size data were compared using five different growth models and found a two-parameter von Bertalanffy growth function (VBGF), the Gompertz model and a modified VBGF fit best for males, females and sexes combined, respectively. Maturity was achieved before 1 year. However, growth did not cease with the onset of maturity, but instead slowed down. Results from marginal increment analysis and edge analysis indicated a nonannual somatic growth pattern with influences from the biannual reproduction cycle where peaks in resource allocation may be focused on ovulation rather than growth during March when larger brood sizes are present, while resources may be allocated more towards growth during August and September when brood sizes are generally smaller. These results may be used as a proxy for species with similar reproductive patterns or for those that lack annual or seasonal growth patterns.
Asunto(s)
Rajidae , Femenino , Masculino , Animales , Reproducción , Tamaño Corporal , Periodicidad , EcosistemaRESUMEN
Phascolosoma (P.) varians, a sipunculan species known from the Greater Caribbean, was designated as a synonym of Phascolosoma (P.) nigrescens, which was originally described from Fiji. Their synonymy was primarily based upon an interpretation that these two species were morphologically indistinguishable. After its designation as a synonym, no further detailed analyses of morphological or molecular characteristics were performed to corroborate the assumed widespread distribution of Phascolosoma (P.) nigrescens. In this study, Phascolosoma (P.) varians is redescribed, and notable differences between this species and its proposed senior synonym are presented. These two species differ in the shape of their hooks, the spatial attachment of nephridia to the body wall, and the morphology of the contractile vessel. Additionally, there is high genetic divergence between nucleotide sequences within their respective cytochrome c oxidase subunit 1 (COI) genes, which supports the morphological data. Herein, the synonymy of Phascolosoma (P.) varians with Phascolosoma (P.) nigrescens is rejected due to morphological and molecular differences. Furthermore, the assumed widespread distribution of Phascolosoma (P.) nigrescens is still considered as questionable.
RESUMEN
Distributed in tropical and warm-temperate waters worldwide, Lobophora species are found across the Greater Caribbean (i.e., Caribbean sensu stricto, Gulf of Mexico, Florida, the Bahamas, and Bermuda). We presently discuss the diversity, ecology, biogeography, and evolution of the Greater Caribbean Lobophora species based on previous studies and an extensive number of samples collected across the eastern, southern, and to a lesser extent western Caribbean. A total of 18 Lobophora species are now documented from the Greater Caribbean, of which five are newly described (L. agardhii sp. nov., L. dickiei sp. nov., L. lamourouxii sp. nov., L. richardii sp. nov., and L. setchellii sp. nov.). Within the Greater Caribbean, the eastern Caribbean and the Central Province are the most diverse ecoregion and province (16 spp.), respectively. Observed distribution patterns indicate that Lobophora species from the Greater Caribbean have climate affinities (i.e., warm-temperate vs. tropical affinities). In total, 11 Lobophora species exclusively occur in the Greater Caribbean; six are present in the western Atlantic; two in the Indo-Pacific; and one in the eastern Pacific. Biogeographic analyses support that no speciation occurred across the Isthmus of Panama, and that the Greater Caribbean acted as a recipient region for species from the Indo-Pacific and as a region of diversification as well as a donor region to the North-eastern Atlantic. The Greater Caribbean is not an evolutionary dead end for Lobophora, but instead generates and exports diversity. Present results illustrate how sampling based on DNA identification is reshaping biogeographic patterns, as we know them.
Asunto(s)
Phaeophyceae , Región del Caribe , Ecología , Florida , Golfo de México , FilogeniaRESUMEN
Pulley Ridge, a limestone ridge that extends nearly 300 km along the southwestern Florida shelf in the eastern Gulf of Mexico, supports a mesophotic coral ecosystem (59 to 94 m deep), surrounded by deeper waters. An ongoing evaluation of Porifera biodiversity observed and collected during expeditions by Harbor Branch Oceanographic Institute (2003-2015) have shown the existence of approximately 102 sponge species, with at least 20 species new to science. The present paper describes two novel Poecilosclerida from mesophotic reefs and deep escarpments in the Pulley Ridge Region, Eastern Gulf of Mexico, namely Discorhabdella ruetzleri n.sp. (Crambeidae, Poecilosclerida) and Hymedesmia (Hymedesmia) vaceleti n. sp. (Hymedesmiidae, Poecilosclerida). This is the first record of Discorhabdella for the greater Caribbean and the Central West Atlantic. The skeleton of D. ruetzleri n.sp. includes the unique pseudoastrose acanthostyles of the genus, and it is distinct from congeners in the size ranges of the megascleres and in the occurrence of predominantly smooth instead of tuberose choanosomal and ectosomal subtylostyles. The intense blue color and the spicule combination of Hymesdesmia (H.) vaceleti n.sp. makes this species unique among other Hymedesmia spp. from the western Atlantic. The discovery represents a considerable expansion in the known biogeographical distribution of the genus Discorhabdella which is represented now by six species with a discrete geographic distribution (New Zealand, Azores, Western Mediterranean Sea, Eastern Pacific in Panama). This work is the first contribution to an ongoing effort to discover and document the importance of sponge biodiversity on mesophotic reefs and associated deep-water habitats in the Gulf of Mexico and the Caribbean.
Asunto(s)
Arrecifes de Coral , Ecosistema , Animales , Golfo de México , PoríferosRESUMEN
The Indo-West Pacific (IWP) coral-reef damselfish Neopomacentrus cyanomos is well established across the south-west Gulf of Mexico (SwGoMx). Comparisons of mtDNA sequences of the SwGoMx population with those from conspecifics from 16 sites scattered across its native geographic range show that the SwGoMx population is derived from two of four native lineages: one from the north-west Pacific Ocean, the other from the northern Indian Ocean. Three hypotheses address how this species was introduced to the SwGoMX: (1) aquarium release; (2) borne by cargo-ship; and (3) carried by offshore petroleum platform (petro-platform). The first is unlikely because this species rarely features in the aquarium trade, and "N. cyanomos" traded to the USA from the sole IWP source we are aware of are a misidentified congener, N. taeniurus. The second hypothesis is unlikely because shipping has not been associated with the introduction of alien damselfishes, there is little international shipping between the IWP and the SwGoMx, and voyages between those areas would be lengthy and along environmentally unfavorable routes. Various lines of evidence support the third hypothesis: (i) bio-fouled petro-platforms represent artificial reefs that can sustain large and diverse populations of tropical reef-fishes, including N. cyanomos in the SwGoMx; (ii) relocation of such platforms has been implicated in trans-oceanic introductions leading to establishment of non-native populations of such fishes; and (iii) genetic characteristics of the SwGoMx population indicate that it was established by a large and diverse group of founders drawn from the IWP regions where many petro-platforms currently in the SwGoMx and other Atlantic offshore oilfields originated.