New light on the nomenclature, taxonomy, and biology of Hemipholis species (Echinodermata: Ophiuroidea: Ophiactidae)

Zootaxa ◽  
2011 ◽  
Vol 3048 (1) ◽  
pp. 44 ◽  
Author(s):  
GORDON HENDLER
Keyword(s):  
Water Temperature ◽  
Cold Tolerance ◽  
Coastal Water ◽  
Brittle Star ◽  
Eastern Pacific ◽  
Warm Water ◽  
Western Atlantic ◽  
Boundary Currents ◽  
Incertae Sedis ◽  
Nomen Novum

Hemipholis cordifera is the correct name for the only known Western Atlantic species of Hemipholis. Hemipholis elongata, a name which has been used in place of H. cordifera, is a nomen dubium that cannot unambiguously be assigned to any known species of brittle star. Evidence is presented that the genus Hemipholis presently comprises only H. cordifera and its geminate Eastern Pacific congener Hemipholis gracilis, and it is shown that the latter name has priority over Hemipholis affinis. Hemipholis gracilis and H. cordifera are illustrated and compared to show how mature individuals can be distinguished. However, small individuals of both species are extremely similar. The latitudinal distributions of H. cordifera and H. gracilis appear to be causally related to coastal water temperature, possibly in conjunction with divergent ocean currents, and the relatively broad range of H. cordifera compared to H. gracilis is attributed to its cold tolerance and to the influence of widespread warm-water boundary currents in the central Western Atlantic. As regards the two other congeners that have been described, Hemipholis wallichii is revealed to be a juvenile ophiuroid incertae sedis, and Hemipholis microdiscus was previously transferred to the Amphiuridae and assigned the nomen novum, Amphiura microdiscoida.

Occurrence and biogeographic significance of Heliaster (Echinodermata: Asteroidea) from the Pliocene of southwest Florida

1988 ◽  
Vol 62 (01) ◽  
pp. 126-132 ◽  
Author(s):  
Douglas S. Jones ◽  
Roger W. Portell
Keyword(s):  
Central American ◽  
Eastern Pacific ◽  
Whole Body ◽  
Marine Fauna ◽  
Western Atlantic ◽  
Southwest Florida ◽  
Extant Species ◽  
Geologic Record ◽  
Central American Isthmus

Whole body asteroid fossils are rare in the geologic record and previously unreported from the Cenozoic of Florida. However, specimens of the extant species,Heliaster microbrachiusXantus, were recently discovered in upper Pliocene deposits. This marks the first reported fossil occurrence of the monogeneric Heliasteridae, a group today confined to the eastern Pacific. This discovery provides further non-molluscan evidence of the close similarities between the Neogene marine fauna of Florida and the modern fauna of the eastern Pacific. The extinction of the heliasters in the western Atlantic is consistent with the pattern of many other marine groups in the region which suffered impoverishment following uplift of the Central American isthmus.

Distribution, history, and taxonomy of the Thais clade (Gastropoda: Muricidae) in the Neogene of tropical America

2001 ◽  
Vol 75 (3) ◽  
pp. 697-705 ◽  
Author(s):  
Geerat J. Vermeij
Keyword(s):  
New Species ◽  
South Atlantic ◽  
Eastern Pacific ◽  
Caribbean Region ◽  
Large Species ◽  
The South ◽  
Western Atlantic ◽  
Extinction Rates ◽  
Tropical America ◽  
The Caribbean

The earliest known members of the Thais clade of rapanine muricid neogastropods comprise four species from the Cantaure Formation (early Miocene: Burdigalian) of Venezuela; three of these species are new. Neorapana rotundata Gibson-Smith et al., 1997, is most closely related to the Recent Pacific Mexican N. tuberculata (Sowerby, 1835), and represents the only known Atlantic occurrence of the genus. Thais brevicula new species is closest to T. callaoensis (Gray, 1828) from the Recent of northern Peru and the Galápagos. A review of the genus Thais indicates that the typical members of this group occur in the South Atlantic, West Africa, and eastern Pacific, but not in the Recent fauna of the southern Caribbean. Stramonita bifida new species is a large species related to the Recent S. haemastoma floridana (Conrad, 1837), which occurs throughout the Caribbean. A review of American species of Stramonita indicates that the taxon S. biserialis (de Blainville, 1832) from the Recent fauna of the eastern Pacific, and the taxon S. h. haemastoma (Linnaeus, 1767), may each be composed of more than one species despite the teleplanic dispersal of their larvae. Stramonita semiplicata new species is closely related to the Recent S. bicarinata (de Blainville, 1832) from the South Atlantic, and represents a lineage that occurred in the Caribbean region until at least the late Miocene. It may have given rise to the eastern Pacific genus Acanthais. The higher diversity and greater antipredatory specialization of eastern Pacific as compared to western Atlantic members of the Thais clade may have resulted from higher post-Miocene rates of speciation and lower extinction rates in the eastern Pacific.

Patterns of morphological diversity among and within arcid bivalve species pairs separated by the Isthmus of Panama

2001 ◽  
Vol 75 (3) ◽  
pp. 590-606 ◽  
Author(s):  
Peter B. Marko ◽  
Jeremy B. C. Jackson
Keyword(s):  
Morphological Variation ◽  
Fossil Record ◽  
Eastern Pacific ◽  
Nominal Species ◽  
Western Atlantic ◽  
Isthmus Of Panama ◽  
Species Pairs ◽  
Recent Species ◽  
Discriminant Analyses ◽  
Collection Sites

Geminate species are morphologically similar sister-species found on either side of the Isthmus of Panama. The existence of all geminates in the tropical Eastern Pacific ocean and the Caribbean Sea is most often explained by vicariance: closure of the Central American Seaway 3.1 to 3.5 Ma simultaneously isolated populations of species with amphi-American distributions. In this paper, we test the potential of morphological measurements for discriminating between Recent geminate species pairs from three genera (Arca, Arcopsis, and Barbatia) in the bivalve family Arcidae and examine the prospects for distinguishing nominal species in the fossil record. Fourteen morphological variables were used to characterize shell shape and multivariate methods were used to discriminate between five Recent species pairs. Collection sites were also used as a priori groups for discrimination to describe patterns of intraspecific morphological variation and to evaluate differences among samples from different geographic regions.On average, 84 percent of specimens within geminate pairs are classified correctly following five separate discriminant analyses with nominal species as the grouping variable. Although all but one arcid species pair are discriminated with high statistical significance, some collection sites within species are highly morphologically distinct. Overall, a large proportion of specimens from each collection locality (79 percent on average) can be classified correctly to site although no single site possessed a multivariate centroid that was significantly different from all other conspecific centroids. The distinctiveness of some collection sites, however, raises the possibility that some nominal species may harbor cryptic species, indicating the need for wider geographic surveys of both molecular and morphological variation within geminate species pairs.The eigenvalue coefficients derived from the Recent samples of one geminate pair (Arca mutabilis and A. imbricata) were used to assess the potential for identifying arcid species in the fossil record. Discriminant analyses of fossil Arca indicate that the forms that characterize Recent A. mutabilis and A. imbricata are present in the fossil record as far back as the Late Early Miocene, in the Cantaure Formation of Venezuela. Because a deep water connection between the Eastern Pacific and Western Atlantic existed until the Middle Miocene, the morphological differences associated with Recent A. mutabilis and A. imbricata likely existed well before the rising Isthmus affected ocean circulation patterns in tropical America. Therefore, despite great overall morphological similarity, these putative geminate species likely have a time of divergence that is at least four times older than final seaway closure. The geographic distribution of fossils also suggests that morphological forms associated with each Recent species had amphi-American distributions both before and after isthmus formation but are now geographically restricted to either side of the isthmus in the Recent fauna.

scholarly journals REVISIÓN TAXONÓMICA DE LA FAMILIA ANTENNARIIDAE PARA COLOMBIA (PISCES: LOPHIIFORMES), INCLUYENDO UN NUEVO REGISTRO DE ANTENNARIUS

2016 ◽  
Vol 36 ◽  
Author(s):  
Luz M. Mejía Ladino ◽  
Arturo Acero P. ◽  
Luz S. Mejía M. ◽  
Andrea Polanco F.
Keyword(s):  
Common Species ◽  
Eastern Pacific ◽  
Western Atlantic ◽  
The Pacific ◽  
The Family ◽  
The Caribbean

The family Antennariidae is represented by two genera (Antennarius and Histrio) and seven species in the Western Atlantic, and by two genera (Antennarius and Antennatus) and five species in the Eastern Pacific. All the species are known from Colombian waters, with the exception of Antenanrius coccineus. In this study we review the family Antenariidae in Colombia, based on the examination of 51 specimens. Antennarius radiosus is first recorded from the Colombian Caribbean, based on two specimens collected with trawls at 20 m depth in Buritaca (Magdalena) and Isla Fuerte (Córdoba). Antennarius radiosus, Antennarius bermudensis, Antennarius multiocellatus, Antennarius ocellatus and Antennarius pauciradiatus are restricted to the Western Atlantic. The most common species found in Colombian seas are Antennarius striatus in the Caribbean and Antennarius avalonis in the Pacific. Histrio histrio is the only species with an almost circumglobal distribution. A key to identify antenariid fishes from Colombia is provided.

A review of the records of Pachycheles rugimanus A. Milne-Edwards, 1880 (Crustacea: Decapoda: Anomura: Porcellanidae) from Brazil, with the description of a new species

Zootaxa ◽  
2019 ◽  
Vol 4568 (1) ◽  
pp. 185 ◽  
Author(s):  
LUCIANE AUGUSTO DE AZEVEDO FERREIRA ◽  
MARCOS TAVARES
Keyword(s):  
New Species ◽  
Morphological Characters ◽  
The Other ◽  
Eastern Pacific ◽  
Brazilian Coast ◽  
Galapagos Island ◽  
Western Atlantic ◽  
The Third ◽  
Cocos Island ◽  
A New Species

All previous records of Pachycheles rugimanus A. Milne-Edwards, 1880, from the Brazilian coast are reviewed and prove to represent a new species, P. coelhoi sp. nov. (from Amapá, northern Brazilian coast), and P. ackleianus A. Milne-Edwards, 1880, a species already known from Brazil (from Pará to Rio de Janeiro). The new species is described and illustrated, and compared to its most similar congeners: P. rugimanus and P. ackleianus from the western Atlantic, and P. velerae Haig, 1960, from the eastern Pacific (Galapagos Island and Cocos Island). Pachycheles coelhoi sp. nov. is distinguishable from the other three species by a suite of morphological characters, which include the ornamentation of the carapace and chelipeds, and the shape of the third thoracic sternite. All previous records of P. rugimanus from Brazil are considered invalid. 

scholarly journals Mechanisms of Future Changes in Equatorial Upwelling: CMIP5 Intermodel Analysis

2020 ◽  
Vol 33 (2) ◽  
pp. 497-510 ◽  
Author(s):  
Mio Terada ◽  
Shoshiro Minobe ◽  
Curtis Deutsch
Keyword(s):  
Climate Models ◽  
Eastern Pacific ◽  
Trade Wind ◽  
Pacific Basin ◽  
Ekman Pumping ◽  
Equatorial Atlantic ◽  
Western Atlantic ◽  
Near Surface ◽  
The Pacific ◽  
Equatorial Upwelling

AbstractThe future change in equatorial upwelling between 1971–2000 and 2071–2100 is investigated using data from 24 coupled climate models. The multimodel ensemble (MME) mean exhibits substantial equatorial upwelling decrease in the eastern Pacific and weaker decrease in the western Atlantic Ocean. The MME mean of upwelling change and intermodel variation of that are decomposed into distinct isopycnal and diapycnal components. In the Pacific, the diapycnal upwelling decreases near the surface, associated with a weakened Ekman pumping. The isopycnal upwelling decreases at depths of 75–200 m around the core of the Equatorial Undercurrent (EUC) due to flattening of the density layer in which it flows. Both the weakened Ekman pumping and the EUC flattening are induced by the locally weakened trade wind over the eastern Pacific basin. In the equatorial Atlantic, both the change in MME mean and the intermodel variation of upwellings are significantly related to the weakened trade wind and enhanced stratification, although these drivers are not independent. The results for the Pacific Ocean imply that future reduction in upwelling may have impacts at different depths by different mechanisms. In particular, the rapid warming of sea surface temperature in the eastern Pacific basin may be mainly caused by the near-surface diapycnal upwelling reduction rather than isopycnal upwelling reduction associated EUC flattening, which is important at deeper levels.

A Rare Record of the Salp, Thetys Vagina (Tunicata: Thaliacea) From Western Scottish Waters

1996 ◽  
Vol 76 (3) ◽  
pp. 833-834 ◽  
Author(s):  
David W. Sims
Keyword(s):  
Hawaiian Islands ◽  
Open Ocean ◽  
Warm Water ◽  
Short Paper ◽  
Oceanic Water ◽  
Western Atlantic ◽  
Total Length ◽  
Asexual Form ◽  
Solitary Form ◽  
Sexual Form

There are no species of salps (Order: Salpida) indigenous to British waters. Those species that can be found, the most abundant being Salpa fusiformis Cuvier (Fraser, 1981) are carried to British and Irish waters from the open ocean of the western Atlantic. Because of this salps can be good indicators of oceanic water movements near to Britain (Fraser, 1981). The largest species of the Salpidae is Thetys vagina (Tilesius, 1802) which generally reaches ≥230 mm in total length (TL) in the solitary asexual form and ~250 mm TL in the aggregate sexual form (Metcalf, 1918; Fraser, 1981). However, a solitary form measuring 333 mm TL was caught in a trawl from the Hawaiian islands (Nakamura & Yount, 1958). The distribution of T. vagina is usually limited to warm water throughout the Atlantic, including the Mediterranean, Indian and Pacific Oceans (Berrill, 1950). Up to 1981 there have been only two records of T. vagina in British waters (Fraser, 1981). This short paper describes, to the best of my knowledge a third recording of this salp from British waters.

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