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 7,600 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. Using 36 newly vetted fossil calibrations, we infer that brachyurans most likely diverged in the Triassic, with family-level splits in the late Cretaceous and early Paleogene. By contrast, the root age is underestimated with automated sampling of 328 fossil occurrences explicitly incorporated into the tree prior, suggesting such models are a poor fit under heterogeneous fossil preservation. We apply recently defined trait-by-environment associations to classify a gradient of transitions from marine to terrestrial lifestyles. We estimate that crabs left the marine environment at least seven and up to 17 times convergently, and returned to the sea from non-marine environments at least twice. Although the most highly terrestrial- and many freshwater-adapted crabs are concentrated in Thoracotremata, Bayesian threshold models of ancestral state reconstruction fail to identify shifts to higher terrestrial grades due to the degree of underlying change required. Lineages throughout our tree inhabit intertidal and marginal marine environments, corroborating the inference that the early stages of terrestrial adaptation have a lower threshold to evolve. Our framework and extensive new fossil and natural history datasets will enable future comparisons of non-marine adaptation at the morphological and molecular level. Crabs provide an important window into the early processes of adaptation to novel environments, and different degrees of evolutionary constraint that might help predict these pathways.

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. As the specimen does not fit any known pagurid taxon, we regard it to represent a new monotypic genus. We fully describe this new micro-pagurid as Raripagurus roseangelae n. gen., n. sp. and also provide photographs of its live coloration. The CO1 barcode for the holotype in the Barcode of Life Database and GenBank accession number are included as part of the description for any future phylogenetic investigations.

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. closely resembles Paragourretia biffari (Blanco Rambla & Liñero Arana, 1994), another regionally reported species for which photographs and additional illustrations are herein provided. While P. biffari and P. sandrae n. sp. are similar in habitus and known habitat to the more commonly encountered confamilial Dawsonius latispina (Dawson, 1967), the third maxillipeds in Paragourretia bear distinct exopods that are absent in Dawsonius Manning & Felder, 1991. As in eight other world congeners, P. sandrae n. sp. differs from both P. biffari and Dawsonius in lacking triangular ventrolateral projections on the sixth pleomere. It is further distinguished from P. biffari by lacking a distinctly incised notch in the anterodistal margin of the uropodal exopod and by absence of a median terminal spine on the telson. Additional sequence-quality specimens of P. sandrae n. sp. are required to clarify its relationships within the polyphyletic genus Paragourretia on a molecular genetic basis.

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. brasiliensis Schmitt, 1935 or southernmost occurrence of E. talpoida (Say, 1817), may be assignable E. portoricensis as now recognized. Among western Atlantic species, E. portoricensis and E. benedicti have to date been considered to have the dactylus of the first pereopod terminally subacute or sharply pointed, which purportedly separates them from E. brasiliensis and E. talpoida, western Atlantic species in which this article is terminally rounded. However, in E. portoricensis this character varies with specimen size and the magnification at which the distal extreme of the dactylus is examined, being rounded to varying degrees in all but the largest specimens. Even in sexually mature specimens of less than maximum size, this rounded tip is armed by a minute corneous spine in E. portoricensis, although it is less prominent than the terminal spine on the consistently more acute dactylus of E. benedicti at all adult sizes. Also, the carapace color in live specimens of E. portoricensis, as documented for specimens collected in both Belize and Panama, differs from that of E. brasiliensis, E. talpoida, and E. benedicti by typically including longitudinal and diagonal dark bars of olive brown on the branchial regions and a light longitudinal bar marking the posterior quarter of the median line. Posterior to the cervical groove, fine rugae of the carapace that form broken transverse lines are at most little diminished across the mid-dorsal longitudinal line in E. portoricensis and E. benedicti, somewhat more broken in E. brasiliensis, and distinctly diminished to all but absent at the midline in E. talpoida. Previously reported BINs in the Barcode of Life database include sequenced specimens from Costa Rica herein accepted as E. portoricensis. We exclude populations from Brazil that have been mis-assigned to E. portoricensis.

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. However, no definitive characters have been found for its identification on the basis of structural morphology. A second new species is genetically sister to P. tortugae Schmitt, 1933, even though it was regarded in earlier literature as no more than an ecomorphic variant expressing protective coloration related to habitat substrate color. In addition to its unique coloration, subtle distinctions are evident in structural morphology. Both species are formally named with accompanying morphological and color descriptions.

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. Six Xanthoidea families are recognised. Panopeidae and Xanthidae sensu stricto are the two largest family-level clades, which are reciprocally monophyletic. Pseudorhombilidae is nested within and is here treated as a subfamily of Panopeidae. Former subfamilies or tribes of Xanthidae sensu lato are basally positioned clades in Xanthoidea and are here assigned family-level ranks: Garthiellidae, Linnaeoxanthidae, Antrocarcinidae, and Nanocassiopidae. The genera Linnaeoxantho and Melybia were recovered in separate clades with Linnaeoxantho being sister to the family Antrocarcinidae, while Melybia was recovered within the family Panopeidae. The existing subfamily classification of Xanthidae and Panopeidae is drastically restructured with 20 xanthid and four panopeid subfamilies provisionally recognised. Diversification-time analyses inferred the origin of Xanthoidea and Garthiellidae in the Eocene, while the other families originated during the Oligocene. The majority of genus- and species-level diversification took place during the Miocene. Ancestral state reconstruction based on depth of occurrence (shallow vs. deep water) shows some ambiguity for the most recent common ancestor of Xanthoidea and Nanocassiopidae. The most recent common ancestors of Antrocarcinidae and Panopeidae were likely deep-water species, while those of Garthiellidae and Xanthidae were probably shallow-water species. Several shifts in net diversification rates were detected but they were not associated with depth-related habitat transitions.

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. is a specimen previously included in a comparative molecular phylogenetic analysis that showed it to be closely related to, but genetically distinct from, the western Atlantic species Hexapanopeus angustifrons (Benedict Rathbun, 1891). Hexapanopeus klausruetzleri n. sp. differs from this widely reported warm-temperate species in both its smoother carapace and pereopod surfaces and its generally more lobiform anterolateral teeth. The unique male first gonopod of the new species also strongly supports its morphological separation from all known congeners and other superficially similar western Atlantic panopeids with which it might be confused. To date, mature females have not been found, and the limited available collections are restricted to the vicinity of Carrie Bow Cay and nearby waters. Fourteen additional species of small panopeid and pseudorhombilid crabs, similar to Hexapanopeus klausruetzleri n. sp. in size and general habitus, were taken in the course of our studies in Belize. Most have not been previously reported from these waters, and several warrant further study to confirm their identifications.

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. This molecular analysis supported a polyphyletic Diogenidae Ortmann, 1892, although incomplete taxonomic sampling among the genera of Diogenidae limits the utility of this finding for resolving family level relationships. Several hypotheses regarding the evolutionary relationships among hermit crab genera were refuted by the Kishino-Hasegawa (KH). Shimodaira-Hasegawa (SH) and Approximately Unbiased (AU) tree topology tests, among them the hypothesis that Areopaguristes is monophyletic. A lack of support for the monophyly of Areopaguristes calls into question the phylogenetic validity of gill number for the differentiation of Paguristes, Areopaguristes, and Pseudopaguristes. The study was inconclusive with regard to the relationships among these three genera, but previously unknown diversity within both Paguristes and Areopaguristes was demonstrated. Existence of an undescribed species confounded under the name Paguristes tortugae Schmitt, 1933 was supported by genetics, morphology, and coloration. A second undescribed species with remarkable similarity to Areopaguristes hummi Wass, 1955 was discovered based on genetics and coloration.

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. appears to inhabit interstices and cavities of coralline algal rubble, rhodoliths, coral rubble, and other eroded calcareous substrates. Weakly separated from Eutrichocheles Wood-Mason, 1876 on the basis of morphology, present assignments of western Atlantic species to Paraxiopsis de Man, 1905 are regarded as provisional. The new species is described morphologically, and the coloration of freshly captured specimens is documented and compared to related species where possible. Coloration readily distinguishes mature specimens of the new species from Paraxiopsis spinipleura Kensley, 1996, with which it was initially confused. The diagnosis includes GenBank accession numbers for COI sequences to allow future molecular phylogenetic comparisons. Compared to regional species that share a similar dentation or spination on the submedian carina, the pleon of the new species is distinctive in the truncate ventral margin on pleura 2-4, as opposed to being broadly rounded or directed ventrally in an acutely triangular tip. The new species is the eighteenth species of Paraxiopsis worldwide and the ninth from western Atlantic waters, seven of which are now known to range into the Gulf of Mexico. An updated key to western Atlantic members of the genus is provided.

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

The snapping shrimp Leptalpheus forceps (family Alpheidae) has a unique natural history as an infaunal symbiont of larger burrowing crustaceans. The mitogenome of L. forceps was sequenced, the first for a symbiotic representative of the family and the first for a species outside of the genus Alpheus. The complete mitogenome was 15,463 bp in length and included 13 protein-coding genes, 12 tRNAs, and 2 rRNAs. The gene order matched all known alpheid mitogenomes. Similar to other caridean mitogenomes, the nucleotide composition was A + T biased (62%). A maximum-likelihood phylogenetic analysis of caridean mitogenomes strongly supported monophyly of the family Alpheidae.

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. The present specimen was found loose as by-catch in a dredged rhodolith sample taken for algal life history studies. In situ, it likely occupied a cavity within one of the collected calcareous rhodoliths or small sponges in the by-catch. While our description is based on a single female specimen, the holotype is fully mature and intact, and it was solidly frozen in seawater until its coloration could be photographically documented and tissues extracted for sequencing. In comparison to the three other known western Atlantic species, the frontal rim of the carapace shield in the new species is continuous between the blunt lateral teeth as in C. ornatus Benedict, 1901 and C. viridis Mayo, 1873, and thus distinct from the subdivided front found in C. spongicola Benedict, 1901. The rim itself is somewhat flattened as in C. ornatus rather than inflated as in C. viridis. However, each of the ocular scales bears a pair of spines at the tip, as in C. viridis. The lower palms of the chelipeds, while distinctly rugose, do not have a separated patch of stridulating ridges comparable to those reported for C. spongicola. The yellow-orange to deep-orange pigmentation of the color pattern differs from fresh coloration in both C. ornatus and C. viridis, but that of C. spongicola is unknown for other than preserved specimens. Description of the single available specimen is in this case justified by the low likelihood for timely acquiring of additional samples from the type locality or adjacent habitats, most of which are deep banks warranting protection under pending habitat management changes. Our diagnosis includes GenBank accession numbers for COI sequences to facilitate future molecular phylogenetic comparisons.

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. The description is based upon a number of specimens previously misidentified as Micropanope truncatifrons Rathbun, 1898, including one so represented in recent molecular phylogenetic analyses. As restricted, Micropanope truncatifrons remains known with certainty from only the limited type series, which does not include a mature male, and sequence quality tissues are not available for molecular phylogenetic analyses. Its generic placement remains questionable following morphological study of its type materials and comparisons to specimens representing other present and former members of Micropanope Stimpson, 1871. Those comparisons underscore that morphological and molecular distinctions warrant assignment of Micropanope pusilla A. Milne-Edwards, 1880 to a new genus, herein designated as Pseudopanopeus n. gen.

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. Morphological characters presently used to distinguish species of Austinixa are not synapomorphic at higher levels and therefore cannot be used to infer cladistic relationships among them. High genetic and morphological intraspecific variation was observed, consistent with patterns of restricted gene flow likely attributable to climatic and geographic history, physical characteristics of contemporary habitats, and host-related constraints on the symbiotic life styles of Austinixa spp. Molecular and morphological characters warrant description of three new species, herein named and illustrated: Austinixa cuestai sp. nov., from Pacific waters of Panama and Nicaragua; Austinixa artankeri sp. nov., from the Caribbean waters of Panama, Colombia, and Venezuela; and Austinixa roblesi sp. nov., from Belize and Panama. All three species inhabit intertidal zones, as do their congeners. To facilitate comparisons and augment the very limited original description, a redescription of the Pacific species Austinixa felipensis (Glassell, 1935) is provided on the basis of paratypes labelled by Glassell and more recently collected topoptypic specimens.

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. To date, the species remains known from only two western Gulf of Mexico sites, both of which are wave-washed intertidal rocky habitats where substrates are heavily burrowed by boring bivalves and sipunculans. While we cannot exclude the possibility that the species was introduced, recurrent collections show its populations to be at very least persistent, the species most likely being a long-overlooked among a confusing hard-substrate assemblage of small panopeid crabs.

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. The other known species of this genus are also typically found in offshore waters of continental shelves, but are all restricted in distribution to the Indo-West Pacific and are known from relatively few specimens. Collections of this new Gulf of Mexico representative of the genus are all from slightly deeper waters than for other known congeners, and commonly occur near hydrocarbon seeps, on some occasions being directly associated with sulfidic substrates that include waxy crude oil globules.

A new genus and species of xanthoid crab (Decapoda: Brachyura) from offshore hard bank habitats in the Gulf of Mexico.

Speciose populations of small xanthoid crabs on offshore banks and reefs of the northern Gulf of Mexico include a new species that is not assignable to presently named genera. Morphological diagnoses of the new genus and species are underpinned by previously published gene sequence analyses, originally misattributed to another species but now known to apply to this taxon. Herein named Guinope tiara n. gen., n. sp., the species shows molecular phylogenetic affinities with the family Linnaeoxanthidae Stevcic, 2005, an ally of panopeid and pseudorhombilid crabs. Specimens from Occulina banks off the Florida Atlantic coast, previously regarded to represent Garthiope barbadensis (Rathbun, 1921), are not that species but instead morphologically assignable to Guinope n. gen. Whether they represent variants of Guinope tiara n. gen, n. sp. or a second species of the genus awaits the collection of fresh materials for DNA analyses.

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 cytochrome c oxidase subunit I (COI) and mitochondrial ribosomal 16S genes for 447 individuals, representing at least 129 morphospecies of decapod crustaceans. COI sequences for 36% (51/140) of the species and 16S sequences for 26% (37/140) of the species were new to GenBank. Automatic Barcode Gap Discovery identified 140 operational taxonomic units (OTUs) which largely coincided with the morphospecies delimitations. Barcode identifications (i.e. matches to identified sequences) were especially useful for OTUs within Synalpheus, a group that is notoriously difficult to identify and rife with cryptic species, a number of which we could not identify to species, based on morphology. Non-concordance between morphospecies and barcode OTUs also occurred in a few cases of suspected cryptic species. As mitochondrial pseudogenes are particularly common in decapods, we investigate the potential for this dataset to include pseudogenes and discuss the utility of these sequences as species identifiers (i.e. barcodes). These results demonstrate that material collected and identified during training activities can provide useful incidental barcode reference samples for under-studied taxa.

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. holthuisi s.s. and from each other, morphological distinctions are subtle and less than absolute in small specimens, being based on ventral spine counts of walking leg dactyls and relative development of the superior crest on the major chela. Molecular phylogenetic analyses clearly support the separation of sister clades, representing two new species, from P. holthuisi s.s. as well as other congeners available for analysis. Both of the new species are presently known to occur widely throughout the northern Gulf of Mexico, though one occurs more commonly in the northeastern and southeastern Gulf, and may range as far south as Suriname. The other has been taken primarily in the northwestern Gulf, and is not known from outside Gulf waters. While both of the new species appear restricted to relatively deep subtidal waters of the continental shelf, Phimochirus holthuisi s.s. is instead more commonly found in shallow nearshore tropical waters on or near coral reefs. Previous literature reports of P. holthuisi usually represent, at least in part, one or both of these two new species.

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. "Glypturus rabalaisae" as originally applied by Sakai (2005) constituted a nomen nudum, and the name has debatably remained so regarded, since the description in Sakai (2011) failed to clearly account for disposition of a type. In the interest of stability, his 2011 description is herewith regarded to meet minimum ICZN requirements for validity, and the name is conserved. Synonymies, brief diagnoses, and updated ranges are provided for Glypturus rabalaisae and its only known regional congener, G. acanthochirus Stimpson, 1866. Available illustrations of G. rabalaisae are augmented by color photographs.

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., is described and illustrated on the basis of a single ovigerous female specimen from Belize, bordering the northwestern Caribbean Sea. The holotype, an ovigerous female, was taken from an epifaunal accumulation of sponges, ascidians, and hydroids on red mangrove roots suspended in the water column. Superficially resembling Pilumnus floridanus Stimpson, 1871, with which it occurs sympatrically, it is distinguished from this and all other known western Atlantic species on the basis of both morphology and molecular markers.