Neogene Cupuladriidae of tropical America. II: taxonomy of recent Discoporella from opposite sides of the Isthmus of Panama

2008 ◽  
Vol 82 (2) ◽  
pp. 279-298 ◽  
Author(s):  
Amalia Herrera-Cubilla ◽  
Matthew H. Dick ◽  
Joann Sanner ◽  
Jeremy B. C. Jackson
Keyword(s):  
Colony Size ◽  
Morphological Characters ◽  
Sympatric Species ◽  
Eastern Pacific ◽  
Linear Discriminant ◽  
Isthmus Of Panama ◽  
Granule Density ◽  
Tropical America ◽  
Separate Step ◽  
The Caribbean

We used up to 30 morphological characters to discriminate and describe species of the genus Discoporella based on complete colony specimens collected from both coasts of the Isthmus of Panama. The characters included zooidal characters and colony-level characters such as colony size and basal granule density. Species were classified by a series of multivariate cluster and linear discriminant analyses until the majority of specimens were assigned to their putative species with high confidence. In the first phase of the analyses, the colonies were grouped by ocean (Caribbean versus eastern Pacific), discriminated predominantly by colony size and basal granule density, characters that might reflect ecophenotypic responses to different conditions in primary productivity and predation between the two oceans. Further analyses of these two groups separately resulted in the discrimination of seven species. Five new species from the Caribbean (D. scutella, D. peltifera, D. bocasdeltoroensis, D. terminata and D. triangula), and two from the eastern Pacific (D. marcusorum and D. cookae). Of these, D. cookae had been identified previously as D. umbellata, a species once considered cosmopolitan, with a range spanning the Caribbean and eastern Pacific coasts of America. With the exception of one genetically defined clade represented by only two specimens, the correspondence of classification between groups discriminated morphometrically by separate step-wise multivariate analyses and those detected by a previous genetic analysis, ranged from 91% to 100%. In analyses of all specimens combined or separated by ocean, but using the total number of characters, 20% to 30% of the specimens could not be distinguished morphometrically from extremely similar sympatric species or cognate (“geminate”) species from the opposite ocean. Diversity was higher in the Caribbean compared to the eastern Pacific, which reflects a similar pattern recently described for the genus Cupuladria from the same region.

scholarly journals Molluscan diversification and extinction on opposite sides of the Isthmus of Panama

1992 ◽  
Vol 6 ◽  
pp. 144-144
Author(s):  
Jeremy B. C. Jackson ◽  
Peter Jung
Keyword(s):  
Late Miocene ◽  
Eastern Pacific ◽  
Tropical Eastern Pacific ◽  
Early Pliocene ◽  
Isthmus Of Panama ◽  
Late Neogene ◽  
Tropical America ◽  
The Caribbean ◽  
First Time ◽  
Final Closure

Molluscs are the most diverse and abundant tropical American macrofossils, but their distributions and evolution are not well understood. Classic studies by Olsson and Woodring documented a rich Late Miocene to Early Pliocene “Gatunian” fauna throughout the Caribbean and tropical Eastern Pacific, with many species in common between the oceans. This fauna was divided by formation of the Isthmus of Panama, and diverged into distinct Pacific and Caribbean faunas sometime thereafter. Diversity also decreased by about half in the Caribbean. However, the timing, rates and correlation of these major biological changes with changes in environmental conditions have not been resolved because of imprecise dating and taxonomy and failure to consider problems of sampling and biofacies in biological comparisons. We used the newly revised late Neogene stratigraphy for Panama and Costa Rica to date for the first time the radiation and extinction of molluscs on opposite sides of the Isthmus. Data include occurrences throughout tropical America for nearly 100 species of the Strombina-group (Gastropoda, Columbellidae) and for more than 500 gastropod and bivalve genera from 240 Late Miocene to Pleistocene isthmian collections.All evidence suggests that final closure of the Isthmus of Panama occurred between 3.5 and 2.5 My. Subgeneric divergence between the oceans was well developed, and trans-isthmian species were rare by the Early Pliocene, at least 2 Ma before final closure. Caribbean diversity remained high until 1.8 to 1.5 Ma when massive but selective extinction occurred. This was at least 1 Ma after final closure of the Isthmus, and may be correlated with onset of slightly cooler Caribbean sea surface temperatures in the Pleistocene. In contrast, Eastern Pacific diversity did not decline, and even increased during the Pleistocene.

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.

Redescription of Pomatostegus stellatus (Abildgaard, 1789) and P. kroyeri Mörch, 1863 (Polychaeta: Serpulidae) from the Tropical American coasts

Zootaxa ◽  
2021 ◽  
Vol 4970 (3) ◽  
pp. 495-514
Author(s):  
J. PABLO SÁNCHEZ-OVANDO ◽  
J. ROLANDO BASTIDA-ZAVALA
Keyword(s):  
Costa Rica ◽  
Caribbean Sea ◽  
Morphological Characters ◽  
Identification Key ◽  
Eastern Pacific ◽  
Tropical Eastern Pacific ◽  
Tropical Waters ◽  
The Pacific ◽  
Plate Shape ◽  
The Caribbean

Pomatostegus Schmarda, 1861 is a serpulid genus with three recognized species, mostly from tropical waters. Pomatostegus stellatus (Abildgaard, 1789), was described from the Caribbean Sea, and has been widely recorded in the Pacific and Indian oceans; P. kroyeri Mörch, 1863 was described from Puntarenas, Costa Rica; however, most records from the Tropical Eastern Pacific were referred to P. stellatus. In this work, the two species are redescribed using morphological characters. The main differences are in the shape of the Spirobranchus-type collar chaetae, opercular plate shape and the number of “free” circlets of spines without accompanying of opercular plates. Comments about characters of P. actinoceras Mörch, 1863, described from Philippines, and an identification key for the three species, are included. 

Systematics of the bubblegum corals (Cnidaria: Octocorallia: Paragorgiidae) with description of new species from New Zealand and the Eastern Pacific

Zootaxa ◽  
2005 ◽  
Vol 1014 (1) ◽  
pp. 1 ◽  
Author(s):  
JUAN ARMANDO SÁNCHEZ
Keyword(s):  
New Species ◽  
New Zealand ◽  
Deep Water ◽  
Phylogenetic Reconstruction ◽  
Morphological Characters ◽  
Sympatric Species ◽  
The Other ◽  
Eastern Pacific ◽  
Areas Of Endemism ◽  
Sister Relationships

Bubblegum corals, Paragorgiidae, are among the largest and most ecologically important benthic sessile deep-water organisms harboring hundreds of associated. However, no recent reviews of their diversity and systematics are yet available, despite the recent increase in the sampling and fishing of deep-water habitats. This study covers 17 Paragorgiidae species. There were only five previously known species for Paragorgia (P. arborea [Linnaeus], P. johnsoni Gray, P. splendens Thomson & Henderson, P. regalis Nutting [=dendroides Bayer], and P. coralloides Bayer) and just one of Sibogagorgia (S. weberi Stiasny). Eleven new species are described here comprising 9 Paragorgia spp. (P. alisonae, P. kaupeka, P. maunga, P. aotearoa, P. wahine, P. whero, P. yutlinux, P. stephencairnsi, and P. tapachtli) and 2 Sibogagorgia spp. (S. tautahi and S. dennisgordoni). This study also uncovered two areas of endemism for bubblegum corals corresponding to New Zealand and the Eastern Pacific (Mexico to Canada). New Zealand has 6 likely endemic species of Paragorgia (P. alisonae, P. kaupeka, P. maunga, P. aotearoa, P. whero, and P. wahine) and the two new species of Sibogagorgia, whereas P. yutlinux, P. stephencairnsi, and P. tapachtli were collected in the Eastern Pacific. There seem to be a few trans-Pacific species such as P. regalis, and likewise in the Atlantic with P. johnsoni, but it is clear that no other species is as cosmopolitan as P. arborea with discontinuous but bi-polar distribution. There are cases of morphological sister species such as P. johnsoni and P. aotearoa that correspond to the Atlantic and Pacific respectively, but the phylogenetic relationships of the remaining species indicate that most paragorgiid diversity and speciation took place in the Indo-Pacific region, as suggested by a number of sympatric species. Surface sclerites, radiates, exhibit a great deal of variation under the Scanning Electron Microscope (SEM), providing a number of characters for phylogenetic reconstruction, including three kinds of radial ornamentation and several types of surfaces and sub-ornamentation at the ultrastructure level. The three most parsimonious trees of equal length, using morphological characters, showed P. arborea as basal to the rest of the Paragorgia species (using Sibogagorgia as the outgroup), which were divided in two clades. One clade includes the species with asymmetrical surface sclerites with some radial ornaments larger or different than others have ([P. maunga -[P. coralloides-P. tapachtli-P. regalis-P. kaupeka]]). In this clade, P. maunga conserved the basal position in the most parsimonious trees whereas relationships among the other species were not consensual. The other clade comprised species with symmetrical surface sclerites ([[P. splendens-P. wahine] P. alisonae-[P. yutlinux-P. stephencairnsi]-P. johnsoni-P. aotearoa]). P. splendens-P. wahine-P. whero and P. yutlinux-P. stephencairnsi maintained their sister relationships respectively in all most-parsimonious trees but no consensual relationships with respect to and among the other species of the clade. Complete descriptions of described and new species using SEM, species comparisons, character states, and a species key are also provided in this paper.

Description of cryptic taxa within the Alpheus bouvieri A. Milne-Edwards, 1878 and A. hebes Kim and Abele, 1988 species complexes (Crustacea: Decapoda: Alpheidae)

Zootaxa ◽  
2009 ◽  
Vol 2153 (1) ◽  
pp. 1-23 ◽  
Author(s):  
ARTHUR ANKER ◽  
CARLA HURT ◽  
NANCY KNOWLTON
Keyword(s):  
Genetic Data ◽  
Eastern Pacific ◽  
Northeastern Brazil ◽  
Western Atlantic ◽  
Isthmus Of Panama ◽  
Species Complexes ◽  
The Caribbean ◽  
Cryptic Taxa ◽  
Coi Sequences ◽  
Final Closure

Alpheus bouvieri A. Milne-Edwards, 1878 and A. hebes Kim and Abele, 1988 are reviewed based on morphological and genetic data. Alpheus bouvieri, previously believed to be distributed in the eastern Pacific and Atlantic, is restricted to the Atlantic populations; the eastern Pacific populations (A. bouvieri sensu Kim and Abele 1988) are assigned to A. javieri n. sp. A second new species, A. agilis n. sp., closely related to the eastern Pacific A. hebes, is described based on recently collected specimens from the eastern Atlantic (São Tomé, Cape Verde) and western Atlantic (Atol das Rocas off northeastern Brazil). The absence of A. agilis n. sp. (or any other representative of the A. hebes clade) in the Caribbean Sea is likely due to a relatively recent (~1–2 my) extinction. Genetic data (COI sequences) indicates that A. bouvieri and A. javieri n. sp., and A. hebes and A. agilis n. sp. diverged approximately 6 and 7.5 mya, respectively, i.e., around 3 my before the final closure of the Isthmus of Panama.

scholarly journals MORFOLOGÍA EXTERNA Y TERMINOLOGÍA PARA LAS ESPECIES DE MUNIDA (CRUSTACEA: ANOMURA: MUNIDIDAE) DEL ATLÁNTICO Y PACÍFICO ORIENTAL TROPICAL

2016 ◽  
Vol 42 (2) ◽  
Author(s):  
Gabriel R. Navas S. ◽  
Adriana Bermúdez Tobón ◽  
Néstor Hernando Campos C.
Keyword(s):  
Species Identification ◽  
Morphological Study ◽  
Morphological Characters ◽  
Eastern Pacific ◽  
Tropical Atlantic ◽  
Decapod Crustaceans ◽  
Diagnostic Characters ◽  
Continental Shelves ◽  
The Caribbean

The genus Munida is one of the most diverse within the superfamily Galatheoidea. This genus also represents one of the richest and most abundant decapod crustaceans from the continental shelves and upper slopes of the Caribbean and Pacific coasts of Colombia. A morphological study of species of this genus showed taxonomic difficulties mainly due to the lack of topological correspondence of some of the diagnostic characters, confusion in the nomenclature and poor or incomplete descriptions of some species. The majority of the species belonging to the genus Munida found in the tropical Atlantic and eastern Pacific oceans were analyzed. Based on the topological correspondence of several external morphological characters of the examined species, a standardization of the nomenclature of the diagnostic characters for species identification is proposed.

scholarly journals The Neogene tropical America fish assemblage and the paleobiogeography of the Caribbean region

2011 ◽  
Vol 130 (2) ◽  
pp. 217-240 ◽  
Author(s):  
Orangel Antonio Aguilera Socorro ◽  
Maria Inês Feijó Ramos ◽  
Eduardo Tavares Paes ◽  
Sue Anne Regina Ferreira Costa ◽  
Marcelo R. Sánchez-Villagra
Keyword(s):  
Fish Assemblage ◽  
Caribbean Region ◽  
Tropical America ◽  
The Caribbean

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.

Linking the Wrangellia Flood Basalts to the Galápagos Hotspot

2021 ◽  
Author(s):  
J. Gregory Shellnutt ◽  
Jaroslav Dostal ◽  
Tung-Yi Lee
Keyword(s):  
Mantle Plume ◽  
Elevated Temperatures ◽  
Volcanic Rocks ◽  
Thermal Conditions ◽  
Internal Variability ◽  
Eastern Pacific ◽  
Unique Region ◽  
Elemental Ratios ◽  
Trace Elemental ◽  
The Caribbean

Abstract The Triassic volcanic rocks of Wrangellia erupted at an equatorial to tropical latitude that was within 3000 km of western North America. The mafic and ultramafic volcanic rocks are compositionally and isotopically similar to those of oceanic plateaux that were generated from a Pacific mantle plume-type source. The thermal conditions, estimated from the primitive rocks, indicate that it was a high temperature regime (T P > 1550°C) consistent with elevated temperatures expected for a mantle plume. The only active hotspot currently located near the equator of the eastern Pacific Ocean that was active during the Mesozoic and produced ultramafic volcanic rocks is the Galápagos hotspot. The calculated mantle potential temperatures, trace elemental ratios, and Sr-Nd-Pb isotopes of the Wrangellia volcanic rocks are within the range of those from the Caribbean Plateau and Galápagos Islands, and collectively have similar internal variability as the Hawaii-Emperor island chain. The paleogeographic constraints, thermal estimates, and geochemistry suggests that it is possible that the Galápagos hotspot generated the volcanic rocks of Wrangellia and the Caribbean plateau or, more broadly, that the eastern Pacific (Panthalassa) Ocean was a unique region where anomalously high thermal conditions either periodically or continually existed from ~230 Ma to the present day.

scholarly journals An assessment of the taxonomic validity of three species of marsupial frogs (Anura: Hemiphractidae: Gastrotheca) from the Yungas of Bolivia based on external morphology and cranial osteology

Zootaxa ◽  
2021 ◽  
Vol 5068 (2) ◽  
pp. 211-239
Author(s):  
CLAUDIA LANSAC ◽  
RODRIGO AGUAYO ◽  
IGNACIO DE LA RIVA
Keyword(s):  
Principal Component ◽  
Taxonomic Status ◽  
Ct Scanning ◽  
Developmental State ◽  
Morphological Characters ◽  
Biological Entity ◽  
Nominal Species ◽  
Linear Discriminant ◽  
Morphological Studies ◽  
Cranial Osteology

The genus Gastrotheca (Anura: Hemiphractidae) is a group of marsupial frogs particularly diverse in Andean regions. Several taxonomic studies of this genus have been conducted in the humid cloud forests—or Yungas—of the Andean eastern slopes of central Bolivia (departments of Cochabamba and Santa Cruz). Yet, the distinction among three species that occur sympatrically in these forests, G. lauzuricae (proposed as a junior synonym of G. coeruleomaculatus in 2015), G. piperata, and G. splendens, remains unclear since the morphological characters that purportedly support their differentiation are variable and partly shared among them. We have carried out external morphological studies, including multivariate morphometric analyses, to assess how they support the taxonomic status of these three species. We also evaluated characters of the cranial osteology of a sample of six individuals using micro CT-scanning. Principal component and linear discriminant analyses resulted in a great overlap among the putative species. Cranial osteological comparisons did not reveal highly significant differences among them, but suggested that different degrees of hyperossification could be related to the developmental state of individuals. Our results indicate that most morphological and osteological reported differences between the three species likely represent intraspecific variation. Thus, we propose that the three nominal species belong to a single biological entity, for which the name Gastrotheca splendens (Schmidt, 1857) has priority. We also restrict the name Gastrotheca coeruleomaculatus (Werner, 1899) to externally similar congeneric populations from the Yungas forests of department of La Paz, but highlighting the need of a detailed evaluation of their taxonomic identity.  

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