First worldwide molecular phylogeny of the morphologically and ecologically hyperdiversified snapping shrimp genus Alpheus (Malacostraca: Decapoda).

Hyperdiverse animal groups raise intriguing questions regarding the factors that generate and maintain their diversity. The snapping shrimp genus Alpheus (with >300 described species) is a spectacularly diversified group of decapod crustaceans that serves as an exemplary system for addressing evolutionary questions regarding morphological adaptations, symbiosis, cryptic diversity and molecular divergence. A lack of information regarding evolutionary relationships among species has limited investigations into the mechanisms that drive the diversification of Alpheus. Previous phylogenetic studies of Alpheus have been restricted in scope, while molecular datasets used for phylogenetic reconstructions have been based solely on mitochondrial and a handful of nuclear markers. Here we use an anchored hybrid enrichment (AHE) approach to resolve phylogenetic relationships among species of Alpheus. The AHE method generated sequence data for 240 loci (>72,000 bp) for 65 terminal species that span the geographic, ecological and taxonomic diversity of Alpheus. Our resulting, well-supported phylogeny demonstrates a lack of monophyly for five out of seven morphologically defined species groups that have traditionally been used as a framework in Alpheus taxonomy. Our results also suggest that symbiotic associations with a variety of other animals have evolved independently in at least seven lineages in this genus. Our AHE phylogeny represents the most comprehensive phylogenetic treatment of Alpheus to date and will provide a useful evolutionary framework to further investigate questions, such as various modifications of the snapping claw and the role of habitat specialization and symbiosis in promoting speciation. Running head: PHYLOGENY OF THE SNAPPING SHRIMP GENUS ALPHEUS.

Alpheopsis balaeniceps sp. nov., an unusual alpheid shrimp (Decapoda: Caridea) from French Polynesia.

Alpheopsis balaeniceps sp. nov. is described based on a single male specimen from Moorea, French Polynesia. The new species is unique within the genus Alpheopsis Coutière, 1896 in possessing balaeniceps-type setae on the fingers of both chelipeds, being especially well developed on the major chela. Within the family Alpheidae, this feature exists only in some species of the distantly related genus Alpheus Fabricius, 1798, however, only on the minor cheliped. This convergence between Alpheopsis and Alpheus is another example of the remarkable diversity and plasticity of the alpheid chelipeds.

Additional records of the laomediid mud-shrimp genus Naushonia Kingsley, 1897 (Crustacea: Decapoda: Gebiidea), with a revised identification key.

Six species of the peculiar mud-shrimp genus Naushonia Kingsley, 1897 (Laomediidae) from various localities in the world are treated in this study: N. carinata Dworschak, Marin & Anker, 2006 (newly recorded from Japan); N. japonica Komai, 2004 (second record since the original description); N. lactoalbida Berggren, 1992 (newly recorded from Papua New Guinea); N. portoricensis (Rathbun, 1901) (newly recorded from the French Antilles); N. serratipalma Komai & Anker, 2010 (newly recorded from Saudi Arabia); and N. draconis Anker, 2014 (newly recorded from Cuba). A detailed description and new illustrations are provided for N. portoricensis, a species for which a modern description was hitherto unavailable. Gill formula was re-examined in all six species. Colour photographs of living or fresh specimens are provided for most species. A revised key to all known species of Naushonia is presented, a eliminating misinterpretation of an important character in previous keys.

Phylogenetic relationships within the snapping shrimp genus Synalpheus (Decapoda: Alpheidae).

The snapping shrimp genus Synalpheus (Alpheidae) is one of the most speciose decapod genera, with over 160 described species worldwide. Most species live in symbiotic relationships with other marine organisms, such as sponges, corals and crinoids, and some sponge-dwelling species have a highly organized, social structure. The present study is the first worldwide molecular phylogenetic analysis of Synalpheus, based on >2,200 bp of sequence data from two mitochondrial (COI and 16S) and two nuclear (PEPCK and 18S) loci. Our molecular data show strong support for monophyly of three out of six traditionally recognized morphology-based species groups: the S. brevicarpus, S. comatularum and S. gambarelloides groups. The remaining three species groups (S. paulsoni, S. neomeris and S. coutierei groups) are non-monophyletic in their current composition and will need to be either abandoned or taxonomically redefined. We also identified potential cryptic species of Synalpheus in our dataset, using intraspecific and interspecific sequence variation in COI from the taxonomically well-studied S. gambarelloides group to establish a genetic divergence threshold. We then used both genetic divergence and tree-based criteria (reciprocal monophyly) to identify potential cryptic species in the remaining taxa of the genus. Our results suggest the presence of multiple cryptic lineages in Synalpheus, underlining the need for more integrative taxonomic studies-including morphological, ecological, molecular, and color pattern data-in this biologically interesting genus.

Athanas manticolus sp. nov., a new stomatopod-associated alpheid shrimp from Vietnam (Crustacea, Decapoda).

A new species of the alpheid shrimp genus Athanas Leach, 1814 is described based on a single specimen, an ovigerous female from Nha Trang Bay, Vietnam. Athanas manticolus sp. nov. differs from all other species of Athanas by the presence of a small post-rostral tubercle, combined with a minutely toothed rostrum, reduced extra-corneal teeth, and the absence of infra-corneal and supra-corneal teeth. In addition, the new species is characterised by its unique colour pattern, particularly by the red chromatophores disposed in randomly oriented, short, narrow streaks. As its name suggests, A. manticolus sp. nov. is commensally associated with the burrows of the nannosquillid mantis shrimp Bigelowina phalangium (Fabricius, 1798).

Taxonomic notes on some Brazilian species of Synalpheus Spence Bate, 1888, with new records and description of a new species (Decapoda, Alpheidae).

The present report deals with several western Atlantic species of the snapping shrimp genus Synalpheus Spence Bate, 1888 occurring in Brazilian territorial waters. Two species, Synalpheus cf. ruetzleri Macdonald & Duffy, 2006 and Synalpheus yano (Ríos & Duffy, 2007), are recorded from the southwestern Atlantic Ocean and Brazil (Ceará) for the first time; S. yano is also newly reported from the eastern Gulf of Mexico and USA (Florida). Synalpheus androsi Coutière, 1909, a distinctive species previously known in Brazil only from a single unconfirmed record, is confirmed to be present in Brazilian waters based on material from Bahia and Espírito Santo. Synalpheus tenuispina Coutière, 1909, a poorly known species from southern Brazil, is redescribed. Synalpheus ul (Ríos & Duffy, 2007), previously known from Bahia and Alagoas, is reported from Pernambuco based on older "Calypso" material misidentified as Synalpheus longicarpus (Herrick, 1891). A new species from the Synalpheus paraneptunus Coutière, 1909 complex is described as Synalpheus maxillispinus sp. nov. based on three specimens dredged from moderate depths (15-55 m) off southern Bahia and Espírito Santo, eastern Brazil. Finally, an incomplete specimen that appears to belong to a species presently unknown in Brazil is preliminarily reported as Synalpheus sp. gambarelloides group. Illustrations are provided for all reported taxa except for S. ul.

Two new species and two new records of deep-water caridean shrimps from Brazil (Decapoda: Pandalidae, Palaemonidae, Crangonidae).

The present study deals with four species of benthic deep-water caridean shrimps collected on the continental slope off southeastern Brazil, between 360 m and 900 m. The deepwater pandalid Bitias stocki Fransen, 1990, previously known only from a few localities in the eastern Atlantic, is reported for the first time from the western Atlantic (Brazil). The Brazilian material of B. stocki also represents the first record of the genus Bitias Fransen, 1990 in the western Atlantic. The palaemonid Periclimenes tenellus (Smith, 1882), previously known only from South Carolina and New Jersey, USA, is reported for the first time from Brazil, representing a considerable range extension of this uncommon species into the southwestern Atlantic. Another deepwater palaemonid shrimp is described as new: Periclimenes bathyalis sp. nov. The new species is morphologically closest to the echinoid associates Periclimenes milleri Bruce, 1986 and Periclimenes ingressicolumbi Berggren & Svane, 1989. Finally, the bizarre deepwater crangonid genus Prionocrangon Wood-Mason in Wood-Mason & Alcock, 1891 is reported for the first time from Brazil and the southwestern Atlantic, where it is represented by a new species, Prionocrangon brasiliensis sp. nov.

Description and Phylogenetic Position of a New Genus and Species of Deep-Water Alpheid Shrimp Associated with Glass Sponges off New Caledonia (Decapoda: Caridea).

Batellopsis paula gen. et sp. nov., a new hexactinellid-associated alpheid shrimp, is described based on a single specimen collected at a depth of 477-503 m north of Île des Pins, New Caledonia. Batellopsis gen. nov. is part of a clade of four genera all containing hexactinellid-associated species, for which a molecular phylogeny is presented. The evolution of several morphological characters, including orbital teeth, a bulgefossa system on the fingers of the first pereiopod chela, and groups of microserrulate setae on the second pereiopod chela, is discussed in light of phylogenetic results.

Notes on two rare and little-known Indo-Pacific snapping shrimps, Alpheus percyi Coutière, 1908 and A. pseudopugnax (Banner, 1953) (Decapoda, Alpheidae).

Two uncommon, morphologically similar snapping shrimps, Alpheus percyi Coutière, 1908 and A. pseudopugnax (Banner, 1953), are reported from various localities across the Indo-West and Central Pacific. Both species are re-diagnosed based on type specimens and recently collected material; a lectotype is designated for A. percyi. The range of A. pseudopugnax, previously known only from the type locality in Hawaii, is extended considerably to French Polynesia and Reunion Island in the western Indian Ocean. Both A. percyi and A. pseudopugnax present a significant variation in the post-rostral region of the carapace, making identification of specimens based solely on morphology rather difficult. In the field, however, the two species can be easily separated by their diagnostic and very striking colour patterns. Colour patterns also suggest that A. percyi may be more closely related to the species of the A. gracilipes Stimpson, 1860 complex than to A. pseudopugnax.

A remarkable new crab-like hermit crab (Decapoda: Paguridae) from French Polynesia, with comments on carcinization in the Anomura.

Patagurus rex gen. et sp. nov., a deep-water pagurid hermit crab, is described and illustrated based on a single specimen dredged from 400 m off Moorea, Society Islands, French Polynesia. Patagurus is characterized by a subtriangular, vaulted, calcified carapace, with large, wing-like lateral processes, and is closely related to two other atypical pagurid genera, Porcellanopagurus Filhol, 1885 and Solitariopagurus Türkay, 1986. The broad, fully calcified carapace, calcified branchiostegites, as well as broad and rigidly articulated thoracic sternites make this remarkable animal one of the most crab-like hermit crabs. Patagurus rex carries small bivalve shells to protect its greatly reduced pleon. Carcinization pathways among asymmetrical hermit crabs and other anomurans are briefly reviewed and discussed.

Ctenocheloides almeidai sp. nov., a new ghost shrimp from Brazil (Decapoda, Ctenochelidae).

A second species of the ctenochelid genus Ctenocheloides Anker, 2010 is described based on a single female specimen collected on a rocky reef in front of Maceió, Alagoas, northeastern Brazil. Ctenocheloides almeidai sp. nov. represents the first record of Ctenocheloides in the Atlantic Ocean. The new species differs from C. attenboroughi Anker, 2010, the type species from Madagascar, in the number of teeth in the crista dentata of the third maxilliped, the proportions and armature of the major and minor chelipeds, and several other characters. The microhabitats of C. almeidai sp. nov. and C. attenboroughi are remarkably similar: both species inhabit burrows made in rock crevices cemented by compact clay-like silt, at very shallow depths (1-1.5 m). A key to the western Atlantic species of the family Ctenochelidae is provided.

New records of processid shrimps from the Indo-West and East Pacific (Crustacea: Decapoda).

New records are presented for the caridean shrimp family Processidae in Indo-West and East Pacific waters, based mainly on recently collected material. These records highlight that many processid species may be relatively widespread, although the distribution of some species remains imperfectly known. The colour pattern of several species is here documented for the first time, showing its potential use as an additional identification character. The available information on the ecology of the reported species is summarised.

Re-examination of the eastern Pacific and Atlantic material of Alpheus malleator Dana, 1852, with the description of Alpheus wonkimi sp. nov. (Crustacea, Decapoda, Alpheidae).

The bumpy-clawed snapping shrimp, Alpheus malleator Dana, 1852 (Alpheidae), is revised based on the recently collected and older museum material from the eastern Pacific (Panama, Ecuador), Caribbean (Panama, Puerto Rico, Trinidad & Tobago), Brazil (São Paulo), and West Africa (Cape Verde, Senegal, Guinea, Equatorial Guinea, Congo). The eastern Pacific material is assigned to A. wonkimi sp. nov., based on one morphological difference in the colour and thickness of the uropodal spiniform seta, as well as previously published molecular data. The Caribbean, Brazilian and West African material is considered to represent a single, widespread, morphologically variable, amphi-Atlantic taxon, A. malleator. Alpheus pugilator A. Milne-Edwards, 1878 is retained as ajunior synonym of A. malleator, whereas A. tuberculosus Osorio, 1892, A. malleator var. edentatus Zimmer, 1913 and A. belli Coutière, 1898, the latter two based on juvenile specimens, are tentatively placed in the synonymy of A. malleator. Illustrations, including colour photographs, are provided for A. wonkimi sp. nov. and A. malleator and their morphological variability is discussed and illustrated.

A conspicuously coloured new species of the Alpheus macrocheles group from the central Indian Ocean (Decapoda: Alpheidae).

A new snapping shrimp species of the Alpheus macrocheles (Hailstone, 1835) group is described based on a single adult male specimen collected on an exposed forereef near Magoodhoo Island, Faafu Atoll, Maldives. Alpheus dingabadi sp. nov. is one of several species of the A. macrocheles group characterised by the presence of a stout distoventral tooth on the merus of the third pereiopod, but can be separated from all of them by several morphological features, including the unusually long appendix masculina on the second pleopod, as well as by its conspicuous and highly diagnostic colour pattern.

Description of a new genus and new species of deep-water stenopodid shrimp from the western Atlantic, with remarks on Odontozona Holthuis, 1946 and Richardina A. Milne-Edwards, 1881 (Decapoda: Stenopodidea).

A new genus, Jogoya, gen. nov., is established for a new species of stenopodid shrimp, Jogoya alucia sp. nov., the holotype and single specimen of which was collected during a manned submersible dive in the Bahamas in 2019, and two additional specimens collected during earlier expeditions, one also from the Bahamas and one from Anguilla. The new genus appears to occupy an intermediate position between Richardina A. Milne-Edwards, 1881 and Odontozona Holthuis, 1946. Jogoya gen. nov. is characterised by the presence of unusually large spines on the cervical cincture of the carapace, a feature shared with a species originally described as Odontozona foresti Hendrickx, 2002 and herein tentatively transferred to Jogoya gen. nov., as Jogoya foresti (Hendrickx, 2002), comb. nov. The most conspicuous morphological difference between J. alucia sp. nov. and J. foresti is in the armature of the posterior half of the carapace, with the latter species having a post-cervical cincture armed with strong spines, which is absent in the new species. The two species of Jogoya gen. nov. also differ greatly by their colour patterns.

A new deep-water species of Discias Rathbun, 1902 (Decapoda: Caridea: Disciadidae) from the Gulf of Aqaba, northern Red Sea.

A new species of the caridean shrimp genus Discias Rathbun, 1902 is described from the Gulf of Aqaba in the northern Red Sea off the coast of Saudi Arabia. Discias forsskali sp. nov. is unique within the genus Discias, combining the following morphological features: (1) rostrum elongate, triangular, pointed distally, non-lanceolate, with serrations on the lateral margins extending onto the orbital margin; (2) posterodorsal margins of all pleonites smooth, unarmed; (3) mandible with well-developed, biarticulated palp; (4) dactylus of third to fifth pereiopods with row of spinules on ventral margin, dactylus of fifth pereiopod smooth dorsally; (5) uropodal exopod with straight, non-serrated lateral margin; and (6) posterior margin of telson with nine (four pairs + one) spiniform setae. The holotype and single known specimen of the new species, an ovigerous female, was collected by ROV at a depth of 387.4 m.

Revision of Alpheus euphrosyne De Man, 1897 andA. microrhynchus De Man, 1897, with description of three new species and taxonomic remarks on several other morphologically and ecologically similar snapping shrimps (Malacostraca: Decapoda: Alpheidae).

Alpheus euphrosyne De Man, 1897 and A. microrhynchus De Man, 1897, two taxonomically challenging snapping shrimps without extant original type material, are rediagnosed based on recently collected and older museum material and adhering closely to their original descriptions. Two male specimens from Java and Kalimantan are designated as neotypes for A. euphrosyne and A. microrhynchus, respectively. Alpheus tirmiziae Kazmi, 1974 is placed in the synonymy of A. euphrosyne. The distributional range of A. euphrosyne extends from the South China Sea through the Sunda Shelf to the northern Arabian Sea. Alpheus eurydactylus De Man, 1920 is removed from the synonymy of A. euphrosyne and redescribed based on De Man's type material from Java and new material from South-East Asia, Indonesia and northern Australia. Alpheus richardsoni Yaldwyn, 1971, previously often regarded as a subspecies of A. euphrosyne, is confirmed as a valid species morphologically and ecologically distinct from A. euphrosyne. In addition, A. richardsoni is geographically separated from A. euphrosyne, being confined to subtropical and temperate waters of Australia and New Zealand. Alpheus microrhynchus appears to be geographically restricted to South-East Asia, with confirmed records from Thailand, peninsular Malaysia and Borneo, where it occurs in transitional freshwater to brackish water habitats. Alpheus cyanoteles Yeo & Ng, 1996 is currently seen as the only true freshwater snapping shrimp. This unique species is morphologically almost identical with A. microrhynchus and is presently known only from a few localities in southern Thailand, peninsular Malaysia and western Borneo (Sarawak). Three species that were previously confused with A. euphrosyne, A. euphrosyne euphrosyne or A. euphrosyne richardsoni, are described as new to science: A. nomurai sp. nov. from Japan, Korea and Taiwan; A. takla sp. nov. from South-East Asia, Philippines, Indonesia, Papua New Guinea and Australia; and A. mangalis sp. nov. from Singapore, Malaysia, Philippines, Indonesia, northern Australia, Taiwan and possibly New Caledonia. Alpheus takla sp. nov. may represent the largest presently known snapping shrimp, with the total body length reaching 90 mm and the length of the major chela reaching 52 mm; this species, locally known as takla, is consumed in some parts of the Philippines. The taxonomic identity of the material from the western and northern Indian Ocean previously reported as A. euphrosyne euphrosyne remains uncertain. Alpheus malabaricus songkla Banner & Banner, 1966 is tentatively elevated to species rank, as Alpheus songkla stat. nov. This taxon remains problematic, mainly because the original type material from Songkhla Lake, Thailand, is composed exclusively of females; its status is discussed based on the reexamination of type specimens and material tentatively identified as A. cf. songkla, which appears to have some affinities with both A. songkla and A. eurydactylus. In addition, taxonomic, biogeographic and/or ecological remarks are provided for five further species, which in the past were compared with A. euphrosyne, A. richardsoni and A. microrhynchus or are morphologically similar to them. These species are: A. paludicola Kemp, 1915 from India; A. nipa Banner & Banner, 1985 from Indonesia; A. bunburius Banner & Banner, 1982 from western Australia; A. pontederiae de Rochebrune, 1883 from both sides of the Atlantic Ocean; and A. firmus Kim & Abele, 1988 from the tropical eastern Pacific. The heterogeneity of the Panamanian and Mexican material currently assigned to A. firmus is discussed in more detail.

A distinctive new species of the coral shrimp genus Microprosthema Stimpson, 1860 from the Atlantic coast of Florida and Honduras (Decapoda: Stenopodidea: Spongicolidae).

A new species of the spongicolid coral shrimp genus Microprosthema Stimpson, 1860 is described on the basis of three specimens collected by hand while scuba diving off the Atlantic coast of southern Florida, with additional photographic records from Roatan, Honduras. Microprosthema dimitrisorum sp. nov. can be separated from all presently known species of the genus by a unique combination of morphological characters, and most easily, by its highly diagnostic and conspicuous colour pattern consisting of large red spots on most of the body and appendages.

Alpheid shrimps of the genera Athanas Leach, 1814, Athanopsis Coutire, 1897 and Pseudathanas Bruce, 1983 of the coasts of the Arabian Peninsula (Malacostraca: Decapoda: Caridea).

Several species of alpheid shrimps belonging the genera Athanas Leach, 1814, Athanopsis Coutire, 1897 and Pseudathanas Bruce, 1983 (Decapoda: Caridea) are reported based on material collected on the Red Sea coast of Saudi Arabia and in Oman. Athanas claereboudti sp. nov. is described based on specimens from Masirah Island and Bandar Khayran east of Muscat, Oman, whereas A. iranicus Anker, Naderloo & Marin, 2010, A. minikoensis Coutire, 1903, A. parvus De Man, 1910, and a species tentatively identified as A. cf. dentirostris Anker, Jeng & Chan, 2001, are reported from various Omani localities. In the genus Athanopsis, four species are reported, including one species new to science: A. brevirostris Banner & Banner, 1981 from Saudi Arabia, A. dawa sp. nov. and A. rubricinctuta Berggren, 1991 from Masirah Island, Oman, and A. tarahomii Marin, Sheibani & Sari, 2014 from Saudi Arabia. The records of A. rubricinctuta and A. tarahomii represent second findings and significant extensions of their previously known ranges for these species. An important error in the description and illustration of the colour pattern of A. tarahomii is corrected, whereas the colour pattern of A. brevirostris is compared again with that of A. saurus Anker, 2011; the latter species is newly recorded from New Caledonia. The taxonomic identity of A. platyrhynchus Coutire, 1897, the type species of the genus from Djibouti, remains somewhat problematic. Finally, the monotypic genus Alberta Kazmi & Kazmi, 2010 established for Alberta banneri Kazmi & Kazmi, 2010 is placed in the synonymy of Pseudathanas Bruce, 1983 and Pseudathanas banneri (Kazmi & Kazmi, 2010) comb. nov. is reported from Muscat, Oman, for the first time since its original description. The generic diagnoses of Athanas, Athanopsis and Pseudathanas are emended to accommodate new or transferred species. All species reported are illustrated in colour.

Description of a new species of the Alpheus edwardsii group (Decapoda: Alpheidae) with a distinctive colour pattern from the Indo-West Pacific.

A new snapping shrimp species of the Alpheus edwardsii (Audouin, 1826) group is described based on two specimens, one male and one female, collected on shallow-water reef flats of the Southern Ari Atoll in the Maldives, with a photographic record from Cebu in the Philippines. Alpheus octocellatus sp. nov. appears to be morphologically closest to A. edwardsii, A. pareuchirus Coutière, 1905, and A. leptochirus Coutière, 1905, but can be distinguished from all of them by a combination of morphological characters, mainly involving the chelipeds, third maxilliped and pleonal sternites. The new species also has a highly diagnostic colour pattern, with four pairs of conspicuous eyespots distributed in a unique and peculiar pattern on the pleon.