A new species of Cymonomus A. Milne-Edwards, 1880, from the deep waters of the Gulf of Mexico (Crustacea: Brachyura: Cymonomidae).

A new western Atlantic member of the cymonomid crab genus, Cymonomus A. Milne-Edwards, 1880, is described from the continental slope in the northern Gulf of Mexico. While the only two available specimens are poorly preserved and lack appendages, they are clearly distinct from other known members of the genus on the basis of the subangular anterolateral margin of the carapace paired with nearly straight, untapered eyestalks that terminate in a slightly bulbous, well-defined cornea, and antennal peduncles that reach beyond the second article of the antennular peduncle.

Convergent Adaptation of True Crabs (Decapoda: Brachyura) to a Gradient of Terrestrial Environments.

For much of terrestrial biodiversity, the evolutionary pathways of adaptation from marine ancestors are poorly understood and have usually been viewed as a binary trait. True crabs, the decapod crustacean infraorder Brachyura, comprise over 7600 species representing a striking diversity of morphology and ecology, including repeated adaptation to non-marine habitats. Here, we reconstruct the evolutionary history of Brachyura using new and published sequences of 10 genes for 344 tips spanning 88 of 109 brachyuran families.

A new mud shrimp of the genus Paragourretia Sakai, 2004, from the Gulf of Mexico (Crustacea: Decapoda: Ctenochelidae).

A new western Atlantic member of the ctenochelid genus Paragourretia Sakai, 2004 is described to accommodate a single unique specimen collected by dredge on muddy rubble substrates of the continental shelf in the southwestern Gulf of Mexico. Paragourretia sandrae n. sp.

A new genus and species of micro-pagurid hermit crab (Crustacea, Decapoda, Paguridae) from the rariphotic reef zone in Curaçao, Lesser Antilles, Caribbean Sea.

During field investigations of deep-reefs off the coast of Curaçao in the Lesser Antilles, Caribbean Sea, a female specimen was collected of an undescribed micro-pagurid crab with striking dorso-ventral flattening of the right cheliped. It was further characterized by a reduced branchial formula, fourth pereopods with grasping-like spines instead of typically pagurid rasp-like scales, nearly symmetrical uropods and telson, and a minute pair of first pleopods (gonopods). The single specimen was discovered in samples from the rariphotic zone (~130-309 m) obtained using a suction sampler operated from the manned submersible R/V Curasub over cryptic habitats and surfaces populated by communities of sessile macro-organisms.

Redescription of the mole crab Emerita portoricensis Schmitt, 1935 (Crustacea: Decapoda: Hippidae), based on Caribbean populations from Puerto Rico, Belize, Costa Rica, and Panama.

The mole crab Emerita portoricensis Schmitt, 1935 was originally described solely on the basis of few key characters that were not precisely defined, giving reason to question subsequent reports of its distribution. The present study, prompted by recent collections documenting coloration in life, undertakes a comprehensive redescription of the species based on specimens of varied sizes from Puerto Rico, Belize, Costa Rica, and Panama. Collections from the northern Caribbean that at first take appear to represent a northernmost record of E.

A new shallow-water mud crab of the genus Hexapanopeus Rathbun, 1898 from Belize (Crustacea: Decapoda: Panopeidae).

A new species of panopeid crab from shallow coastal waters of Belize is formally described and named based upon comparative study of three small specimens obtained in the course of a regional biodiversity survey of decapod crustaceans. The herein designated holotype of Hexapanopeus klausruetzleri n. sp.

A comprehensive molecular phylogeny of the brachyuran crab superfamily Xanthoidea provides novel insights into its systematics and evolutionary history.

Maximum likelihood and Bayesian phylogenies for the brachyuran crab superfamily Xanthoidea were estimated based on three mitochondrial and four nuclear genes to infer phylogenetic relationships and inform taxonomy. Habitat data was then used in conjunction with several diversification rates analyses (BAMM, BiSSE, HiSSE, and FiSSE) to test evolutionary hypotheses regarding the diversification of xanthoid crabs. The phylogenies presented are the most comprehensive to date in terms of global diversity as they include all four constituent families (Xanthidae, Panopeidae, Pseudorhombilidae, and Linnaeoxanthidae) spanning all oceans in which xanthoid crabs occur.

Two new marine hermit crabs allied with the Paguristes tortugae complex (Crustacea: Decapoda: Anomura) from the western Atlantic.

A recent molecular phylogenetic analysis that focused on selected species of western Atlantic Paguristes Dana, 1851, Areopaguristes Rahayu McLaughlin, 2010, and Pseudopaguristes McLaughlin, 2002 was somewhat inconclusive regarding relationships among those genera, but it revealed two new unrecognized species genetically related to members of the Paguristes tortugae complex. One of the new species is sister to A. hummi (Wass, 1955), which is readily separated from Wass taxon by significant differences in coloration.

Molecular phylogenetic analysis of the Paguristes tortugae Schmitt, 1933 complex and selected other Paguroidea (Crustacea: Decapoda: Anomura).

Morphological characters, as presently applied to describe members of the Paguristes tortugae Schmitt, 1933 species complex, appear to be of limited value in inferring phylogenetic relationships within the genus, and may have similarly misinformed understanding of relationships between members of this complex and those presently assigned to the related genera Areopaguristes Rahayu McLaughlin, 2010 and Pseudopaguristes McLaughlin, 2002. Previously undocumented observations of similarities and differences in color patterns among populations additionally suggest genetic divergences within some species, or alternatively seem to support phylogenetic groupings of some species. In the present study, a Maximum Likelihood (ML) phylogenetic analysis was undertaken based on the H3, 12S mtDNA, and 16S mtDNA sequences of 148 individuals, primarily representatives of paguroid species from the western Atlantic.

Description of Paraxiopsis/ kensleyi/ n. sp., a new axiid lobster from the Gulf of Mexico (Crustacea: Decapoda: Axiidea).

A new species of axiid was discovered during sampling offshore deep banks on the middle continental shelf off Louisiana. Paraxiopsis kensleyi n. sp.

The complete mitochondrial genome of the symbiotic infaunal snapping shrimp (Decapoda, Alpheidae).

The snapping shrimp (family Alpheidae) has a unique natural history as an infaunal symbiont of larger burrowing crustaceans. The mitogenome of was sequenced, the first for a symbiotic representative of the family and the first for a species outside of the genus . The complete mitogenome was 15,463 bp in length and included 13 protein-coding genes, 12 tRNAs, and 2 rRNAs.

A new species of the hermit crab genus Cancellus H. Milne Edwards, 1836 from a mesophotic deep bank in the northwestern Gulf of Mexico (Crustacea: Decapoda: Diogenidae).

Recent sampling on mesophotic deep banks in the northwestern Gulf of Mexico has produced a previously undescribed hermit crab assignable to the genus Cancellus H. Milne Edwards, 1836. Members of the genus are most often found to occupy cavities of eroded coral, siliceous sponges, porous calcareous rock fragments, algal concretions, or worm tubes as shelters.

A new genus and species of mud crab (Crustacea, Brachyura, Panopeidae) from shoreline waters of the western Gulf of Mexico.

Several specimens of a small panopeid crab from coastal waters of the western Gulf of Mexico were long suspected to represent an undescribed species and are herein designated as representatives of a new genus. While the originally collected specimens from over four decades ago were not of gene-sequence quality, later collections from the same locality produced materials that yielded sequence data for inclusion in molecular phylogenetic studies. Building on results of those analyses, the present taxonomic description draws upon morphology to support the description of a unique species in which especially the male first gonopods differ from those of all other described panopeid genera.

Phylogeny of the genus Austinixa Heard amp; Manning, 1997, inferred from mitochondrial and nuclear molecular markers, with descriptions of three new species and redescription of Austinixa felipensis (Glassell, 1935) (Decapoda: Brachyura: Pinnotheridae).

We used the mitochondrial 16S-NADH1 complex, mitochondrial 12S, and nuclear histone 3 genes to examine evolutionary relationships among members of the genus Austinixa Heard Manning, 1997, and their relationships to other pinnotherids. The monophyly of Austinixa was confirmed by maximum likelihood, Bayesian, and maximum parsimony analyses. Clades recovered on the basis of molecular data agreed with current morphology-based taxonomy at species rank.

A new crab of the genus Nanoplax from the Gulf of Mexico, and assignment of Micropanope pusilla to a new genus (Crustacea, Brachyura, Pseudorhombilidae).

Nanoplax thomai n. sp. is described from the Gulf of Mexico, representing the second species of the genus.

A new species of the hairy crab genus Pilumnus (Decapoda: Brachyura: Pilumnidae) from Belize.

A new species of the pilumnid crab genus Pilumnus Leach, 1815, P. mantelattoi n. sp.

A new mud shrimp of the genus Pugnatrypaea from outer continental shelf waters of the northern Gulf of Mexico, commonly associated with hydrocarbon seeps (Crustacea: Decapoda: Callianassidae).

A new species of callianassid mud shrimp is described from outer continental shelf waters of the northwestern Gulf of Mexico, where it appears to commonly live in close association with sediments on or near natural hydrocarbon seeps. Recent genus-level taxonomic revisions of the Callianassidae, based on gene sequence analyses and comparative morphological studies, included specimens representing this new species, assigning it with strong support to the genus Pugnatrypaea Poore et al., 2019.

Documenting decapod biodiversity in the Caribbean from DNA barcodes generated during field training in taxonomy.

DNA barcoding is a useful tool to identify the components of mixed or bulk samples, as well as to determine individuals that lack morphologically diagnostic features. However, the reference database of DNA barcode sequences is particularly sparsely populated for marine invertebrates and for tropical taxa. We used samples collected as part of two field courses, focused on graduate training in taxonomy and systematics, to generate DNA sequences of the barcode fragments of subunit I (COI) and mitochondrial ribosomal 16S genes for 447 individuals, representing at least 129 morphospecies of decapod crustaceans.

Designation of a neotype for Glypturus rabalaisae Sakai, 2011, a ghost shrimp from continental shelf waters of the northern Gulf of Mexico (Crustacea: Decapoda: Callianassidae).

Glypturus rabalaisae Sakai, 2011 was named for type materials identified solely on the basis of illustrations that had been originally reported as "Glypturus acanthochirus" by previous authors (Rabalais et al. 1981). As the voucher specimens for those illustrations (thus the types) are lost, a neotype is designated.

Two new species of the Phimochirus holthuisi complex from the Gulf of Mexico, supported by morphology, color, and genetics (Crustacea: Anomura: Paguridae).

Coloration, gene-sequence data (H3, 12s, 16s), and subtle features in morphology support the description of two new species, both formerly regarded to represent accepted variants of Phimochirus holthuisi s.l. While color in life consistently separates these species from P.

The first zoeal stage morphology of Achelous spinimanus (Latreille), A. gibbesii (Stimpson), and Portunus sayi (Gibbes) (Decapoda, Brachyura) provides support for molecular phylogeny.

Taxonomic rearrangements were recently proposed for some members of Portunus Weber and Cronius Stimpson, including the re-elevation of the status of the subgenus Achelous De Haan to accommodate 21 American species. In the present study the first zoea of Achelous spinimanus, type species of the genus, A. gibbesii and Portunus sayi were obtained from laboratory-hatched specimens.

Possible shell disease in 100 million-year-old crabs.

Modern organisms exhibit evidence of many diseases, but recognizing such evidence in fossils remains difficult, thus hampering the study of the evolution of disease. We report on 2 molts of the goniodromitid crabs Distefania incerta and Goniodromites laevis from the mid-Cretaceous (late Albian) of Spain, with both species exhibiting damage to the dorsal carapace in otherwise well-preserved specimens. The subcircular to quadratical holes, found in <0.

Integrative Taxonomic Study of the Purse Crab Genus Persephona Leach, 1817 (Brachyura: Leucosiidae): Combining Morphology and Molecular Data.

Marine crabs of the genus Persephona Leach, 1817 are restricted to American waters of the western Atlantic and eastern Pacific Oceans. Subfamilial assignment of this taxon has varied between authors and its species composition remain in question. We conducted a comparative study based on morphology and molecular phylogenetics for all ten recognized species of Persephona, along with Iliacantha hancocki.