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Acanthemblemaria aceroi, a new species of tube blenny from the Caribbean coast of South America with notes on Acanthemblemaria johnsoni (Teleostei: Chaenopsidae)
Abstract
Acanthemblemaria aceroi new species is described from the upwelling region of the Caribbean coasts of Venezuela and Colombia. It differs from its closest relative, Acanthemblemaria rivasi Stephens, 1970, known from Panama and Costa Rica, in the posterior extent of the infraorbitals, details of head spination, and unique COI sequences. The description of Acanthemblemaria johnsonsi Almany & Baldwin, 1996, heretofore known only from Tobago, is expanded based on specimens from islands offshore of eastern Venezuela.
... It is worth noting that there is a recently proposed sister species for A. rivasi called A. aceroi. This specie was believed to be in Colombian waters from Santa Marta to Venezuela [68]. However, the separation of the two species was based on meristic and morphological aspects, and the molecular analysis mentioned by Hastings et al. [68] did not include Colombian samples to confirm A. aceroi's presence in Colombia. ...
... This specie was believed to be in Colombian waters from Santa Marta to Venezuela [68]. However, the separation of the two species was based on meristic and morphological aspects, and the molecular analysis mentioned by Hastings et al. [68] did not include Colombian samples to confirm A. aceroi's presence in Colombia. Consequently, we considered A. rivasi as the species present in the Colombian Caribbean for our analysis. ...
Simple Summary
The comparative phylogeography of marine species with contrasting dispersal potential across the southern Caribbean Sea was evaluated by the presence of two putative barriers: the Magdalena River plume (MRP) and the combination of the absence of a rocky bottom and the almost permanent upwelling in the La Guajira Peninsula (ARB + PUG). Samples of each species were collected in five locations from Capurganá to La Guajira. For the first time, sufficient evidence of a phylogeographic break caused by the MRP is provided, mainly for Acanthemblemaria rivasi, a fish in a coral reef. The ARB + PUG barrier causes another break for A. rivasi and Cittarium pica (rocky shore mollusk species). We identified three populations for A. rivasi and C. pica from five locations, while Nerita tessellata presented one population. Acanthemblemaria rivasi and C. pica fit the hierarchical population model and share a similar phylogeographic history. Our results show how the biological traits of these three species and the biogeographic barriers have influenced their phylogeographic structure. Finally, we discussed why the Santa Marta and La Guajira marine sectors are essential for conserving marine species across the southern Caribbean Sea.
Abstract
The comparative phylogeography of marine species with contrasting dispersal potential across the southern Caribbean Sea was evaluated by the presence of two putative barriers: the Magdalena River plume (MRP) and the combination of the absence of a rocky bottom and the almost permanent upwelling in the La Guajira Peninsula (ARB + PUG). Three species with varying biological and ecological characteristics (i.e., dispersal potentials) that inhabit shallow rocky bottoms were selected: Cittarium pica (PLD < 6 days), Acanthemblemaria rivasi (PLD < 22 days), and Nerita tessellata (PLD > 60 days). We generated a set of SNPs for the three species using the ddRad-seq technique. Samples of each species were collected in five locations from Capurganá to La Guajira. For the first time, evidence of a phylogeographic break caused by the MRP is provided, mainly for A. rivasi (AMOVA: ΦCT = 0.420). The ARB + PUG barrier causes another break for A. rivasi (ΦCT = 0.406) and C. pica (ΦCT = 0.224). Three populations (K = 3) were identified for A. rivasi and C. pica, while N. tessellata presented one population (K = 1). The Mantel correlogram indicated that A. rivasi and C. pica fit the hierarchical population model, and only the A. rivasi and C. pica comparisons showed phylogeographic congruence. Our results demonstrate how the biological traits of these three species and the biogeographic barriers have influenced their phylogeographic structure.
... obs.). Recent work in species descriptions of chaenopsids have required CT scanning to determine morphological differences between species (Hastings et al. 2020). ...
Life history characteristics of cryptobenthic reef fishes (CRFs), such as their fast growth and reproductive rates, near-shore larval retention and high turnover, predispose these species to rapid diversification and cryptic speciation. This may be particularly true for isolated CRF populations. The sailfin blenny, Emblemaria pandionis, is widespread throughout the Caribbean and is found on the reefs of the Flower Garden Banks, an isolated reef system in the NW Gulf of Mexico. Using DNA barcoding and multi-locus delimitation, we show that E. pandionis is a species complex comprised of at least four distinct taxonomic units in the Caribbean, one at the Flower Garden Banks, a second in eastern Florida, a third in the central Caribbean and a fourth in Curaçao. The phylogenetic relationships within the E. pandionis species complex are defined by well-established phylogeographic barriers to gene flow in the Caribbean. Populations of E. pandionis from eastern Florida are genetically distinct from populations found in the Bahamas, highlighting the role of the Florida Strait as a strong barrier to gene flow and populations in Curaçao are deeply divergent from all other populations sampled in the Caribbean. Results from this study highlight the roles of isolated reefs and ocean currents in the speciation of cryptobenthic reef fishes.
... The combination of physical, ecological, and biological aspects suggests a vicariant event for A. rivasi because a new species distributed from Santa Marta to Venezuela was recently proposed [A. aceroi, 93 ]. However, the high level of genetic differentiation observed among the three clades (Cabo de la Vela, Santa Marta, and Cartagena+Isla Fuerte+Capurganá; AMOVA: ФCT = 0.495, p < 0.05) suggests a taxonomic revision, which should include the mitochondrial molecular markers, meristic characters, and morphology to determine the existence of a possible additional species in the A. rivasi complex. ...
The comparative phylogeography of marine species with contrasting dispersal potential across the southern Caribbean Sea was evaluated by the presence of two putative barriers: the Magdale-na River plume (MRP) and the combination of the absence of a rocky bottom and permanent upwelling in the La Guajira Peninsula (ARB+PUG). Three species of rocky shallow bottoms were selected with different dispersal potentials: Acanthemblemaria rivasi (PLD < 22 days), Cittarium pica (PLD < 6 days), and Nerita tessellata (PLD > 60 days). We generated a set of SNPs for the three species using the ddRad-seq technique. Samples of each species were collected in five locations from Capurganá to La Guajira. For the first time, evidence of a phylogeographic break caused by MRP is provided, mainly for A. rivasi (AMOVA: ФCT = 0.420). The ARB+PUG barrier causes an-other break for A. rivasi (ФCT = 0.406) and C. pica (ФCT = 0.224). Three populations (K = 3) were identified for A. rivasi and C. pica, while N. tessellata presented one population (K = 1). The Mantel correlogram indicated that A. rivasi and C. pica fit the hierarchical population model, and only the A. rivasi and C. pica comparisons showed phylogeographic congruence. Our results demon-strate how the biological traits of these three species and the biogeographic barriers have influ-enced their phylogeographic structure.
Neotropical reef fish communities are species-poor compared to those of the Indo-West Pacific. An exception to that pattern is the blenny clade Chaenopsidae, one of only three rocky and coral reef fish families largely endemic to the Neotropics. Within the chaenopsids, the genus Acanthemblemaria is the most species-rich and is characterized by elaborate spinous processes on the skull. Here we construct a species tree using five nuclear markers and compare the results to those from Bayesian and parsimony phylogenetic analyses of 60 morphological characters. The sequence-based species tree conflicted with the morphological phylogenies for Acanthemblemaria, primarily due to the convergence of a suite of characters describing the distribution of spines on the head. However, we were able to resolve some of these conflicts by performing phylogenetic analyses on suites of characters not associated with head spines. By using the species tree as a guide, we used a quantitative method to identify suites of correlated morphological characters that, together, produce the distinctive skull phenotypes found in these fishes. A time calibrated phylogeny with nearly complete taxon sampling provided divergence time estimates that recovered a mid-Miocene origin for the genus, with a temporally and geographically complex pattern of speciation both before and after the closure of the Isthmus of Panama. Some sister taxa are broadly sympatric, but many occur in allopatry. The ability to infer the geography of speciation in Acanthemblemaria is complicated by extinctions, incomplete knowledge of their present geographic ranges and by wide-spread taxa that likely represent cryptic species complexes.
Background:
Marine allopatric speciation involves interplay between intrinsic organismal properties and extrinsic factors. However, the relative contribution of each depends on the taxon under study and its geographic context. Utilizing sea catfishes in the Cathorops mapale species group, this study tests the hypothesis that both reproductive strategies conferring limited dispersal opportunities and an apparent geomorphologic barrier in the Southern Caribbean have promoted speciation in this group from a little studied area of the world.
Methodology/principal findings:
Mitochondrial gene sequences were obtained from representatives of the Cathorops mapale species group across its distributional range from Colombia to Venezuela. Morphometric and meristic analyses were also done to assess morphologic variation. Along a approximately 2000 km transect, two major lineages, Cathorops sp. and C. mapale, were identified by levels of genetic differentiation, phylogenetic reconstructions, and morphological analyses. The lineages are separated by approximately 150 km at the Santa Marta Massif (SMM) in Colombia. The northward displacement of the SMM into the Caribbean in the early Pleistocene altered the geomorphology of the continental margin, ultimately disrupting the natural habitat of C. mapale. The estimated approximately 0.86 my divergence of the lineages from a common ancestor coincides with the timing of the SMM displacement at approximately 0.78 my.
Main conclusions/significance:
Results presented here support the hypothesis that organismal properties as well as extrinsic factors lead to diversification of the Cathorops mapale group along the northern coast of South America. While a lack of pelagic larval stages and ecological specialization are forces impacting this process, the identification of the SMM as contributing to allopatric speciation in marine organisms adds to the list of recognized barriers in the Caribbean. Comparative examination of additional Southern Caribbean taxa, particularly those with varying life history traits and dispersal capabilities, will determine the extent by which the SMM has influenced marine phylogeography in the region.
Acanthemblemaria johnsoni is described from six specimens collected from shallow coral reefs at the north end of the Caribbean island of Tobago. The new species differs from all other Atlantic species of Acanthemblemaria by the combined spinous and soft dorsal-fin ray count of XXIV, 12-13. Evolutionary relationships of the new species are discussed in relation to the phylogeny of the genus proposed by Hastings (1990).
Seven new species of chaenopsid blennies are described from the western Atlantic: Emblemariopsis leptocirris, Emblemariopsis occidentalis, Emblemaria caldwelli, Emblemaria diphyodontis, Emblemaria biocellata, Emblemaria culmenis, and Acanthemblemaria rivasi. The genus Pseudemblemaria Stephens 1961 is synonymized with Emblemariopsis Longley 1927 and the latter redefined. The description of the Chaenopsidae (inae) and the species Emblemariopsis bahamensis and Ekemblemaria nigra are supplemented. Cranial sensory pores are analyzed as a generic characteristic.
A parsimony analysis of the relationships of Acanthemblemaria species was conducted based on 60 morphological characters. Outgroups included the two species of Ekemblemaria, the apparent sister group of Acanthemblemaria, and a hypothetical outgroup based on character state distributions within potential second outgroups. The monophyly of Acanthemblemaria, containing 17 species, is supported by 5 synapomorphies: a fleshy or ossified process on the nasal bone adjacent to the first anterofrontal pore, spines on the raised ridges of the frontals, serrations or spines on the orbital margin of the frontal, serrations or spines on the orbital margin of the lateral ethmoid, and two rows of palatine teeth. Three equally parsimonious trees were found, and a strict consensus tree revealed that relationships were fully resolved except within a portion of the "hancocki species group" (Fig. 1). Species groups recognized by recent workers were supported and species relationships proved to be highly nested. The two species of Ekemblemaria and two species pairs of Acanthemblemaria follow the eastern Pacific-Caribbean distributional track, with one of the latter indicating a rarely reported relationship between the southern Caribbean and the Galapagos Islands.
The Bahaman species of emblemariid blennies
- J E Böhlke
Böhlke, J.E. (1957) The Bahaman species of emblemariid blennies. Proceeding of the Academy of natural Sciences, Philadelphia, 109, 25-57.
Standard symbolic codes for institutional resource collections in herpetology and ichthyology: an online reference
- M H Sabaj
Sabaj, M.H. (2019) Standard symbolic codes for institutional resource collections in herpetology and ichthyology: an online
reference. Version 7.1. 21 March 2019. American Society of Ichthyologists and Herpetologists, Washington, D.C. Electronically accessible. Available from: https://www.asih.org/ (accessed 29 June 2020)
A new Atlantic species of Acanthemblemaria (Teleostei: Blennioidei: Chaenopsidae): morphology and relationships
- C C Baldwin
- R Betancur-R
- P Acero