Phylogeography of the freshwater crab Potamon persicum (Decapoda: Potamidae): an ancestral ring species?

The Zagros Mountains, characterized by complex topography and three large drainage systems, harbor the endemic freshwater crab Potamon persicum in Iran. Our study delves into the evolutionary history of P. persicum, utilizing two mitochondrial and one nuclear marker. We collected 214 specimens from 24 localities, identifying 21 haplotypes grouped into two major evolutionary lineages. Substantial differentiation exists between drainage systems and lineages. Historical demographic analysis revealed a significant decrease in population size during the late Holocene, accompanied by a recent population bottleneck. Species distribution modeling has revealed eastward shifts in suitable habitats between the last glacial maximum and the present day. Following the last glacial maximum, habitat fragmentation occurred, resulting in the establishment of small populations. These smaller populations are more vulnerable to climatic and geological events, thereby limiting gene flow and accelerating genetic differentiation within species. Historical biogeographic analysis traced the origin of P. persicum to the western Zagros Mountains, with major genetic divergence occurring during the Pleistocene. Our genetic analyses suggest that P. persicum may have shown a genetic pattern similar to a classical ring species before the Pleistocene. The Namak Lake sub-basin could have served as a contact zone where populations did not interbreed but were connected through gene flow in a geographic ring. Currently, genetic separation is evident between basins, indicating that P. persicum in the Zagros Mountains is not a contemporary ring species. Also, our biogeographical analysis estimated that range evolution may have been driven initially by dispersal, and only during the late Pleistocene by vicariance.

Pilumnidae Samouelle, 1819 (Crustacea: Decapoda: Brachyura: Pilumnidae) of the Persian Gulf and Gulf of Oman, with a note on their phylogeny.

Members of the family Pilumnidae are common on intertidal and subtidal tropical and subtropical rocky, coral rubble and mud habitats. In the current study we collected 17 species belonging to 10 genera from the Iranian coast of the Persian Gulf and Gulf of ​​Oman. The species were examined using detailed morphological characteristics and any variation was recorded and compared with material from other geographical regions. Further, we compared 1171 base pairs of two mitochondrial genes (COI and 16S rRNA) and one nuclear gene (H3), and present reference sequences for the regional pilumnids, some of them being the first, as a useful basis for comparison with pilumnids from elsewhere. Two species, Glabropilumnus levimanus and Pilumnopeus africanus, are recorded for the first time from northwestern Indian Ocean, and a possibly undescribed species of Pilumnus was found that requires more detailed study. The results confirmed that the two previously recorded species, Pilumnus minutus De Haan, 1835 and P. vespertilio (Fabricius, 1793) do not occur in the Persian Gulf and Gulf of Oman. The current diversity of Pilumnidae in the region is increased to 28 species in 14 genera. Monophyly of the given genera and species in the study area is well corroborated.

Crustaceans functional diversity in mangroves and adjacent mudflats of the Persian Gulf and Gulf of Oman.

The effects of mangrove vegetation on functional features of crustacean assemblages were investigated using the Biological Traits Analysis (BTA). The study was carried out at four major sites in the arid mangrove ecosystem of the Persian Gulf and Gulf of Oman. Samples of Crustacea and associated environmental variables were taken seasonally (February 2018 and June 2019) from two habitats: a vegetated area with both mangrove trees and pneumatophores, and an adjacent mudflat. In each site, functional traits for the species were assigned using seven categories based on bioturbation, adult mobility, feeding habits and life-strategy traits. The results showed that the crabs (i.e., Opusia indica, Nasima dotilliformis and Ilyoplax frater) were widely distributed across all sites and habitats. The vegetated habitats supported higher taxonomic diversity than the mudflats, which highlights the importance of mangrove structural complexity for crustacean assemblages. Species inhabiting vegetated habitats were characterized by stronger presence of conveyor building species, detritivore, predator, grazer, lecithotrophic larval development, body size of 50-100 mm, and swimmer trait modalities. While, mudflat habitat enhanced the occurrences of surface deposit feeder, planktotrophic larval development, body size of <5 mm, and life span of 2-5 years. The results of our study showed that taxonomic diversity increased from the mudflats to the mangrove vegetated habitats. However, functional diversity did not differ between habitats. The significant differences in species and functional trait composition were observed between vegetated habitats and adjacent mudflats, stressing that different habitats may harbor different species and trait sets, likely as a result of habitat complexity. The use of taxonomic and functional attributes generate complementary information that can helps us to reach more efficient conclusions in terms of biodiversity conservation and ecosystem functionality in mangrove ecosystems.

On the taxonomy of Philyra sagittifera (Alcock, 1896) and P. concinnus Ghani & Tirmizi, 1995 (Decapoda, Brachyura, Leucosiidae), with description of a new genus from the Indian Ocean.

The identity of the leucosiid crabs, Philyra sagittifera (Alcock, 1896) and P. concinnus Ghani & Tirmizi, 1995, originally described from Pakistan is clarified. Redescription of the lectotype male of Philyra sagittifera (Alcock, 1896) and fresh material of both species collected from the Persian Gulf revealed that these two species show significant morphological differences from the generic characters of Philyra sensu stricto and other allied genera in possessing three broad tuberculated ridges united to form a "broad-arrow" pointing forwards on the carapace, and male G1 with apical process curved, with or without a spatulate tip. Therefore, a new genus Tirmilyra n. gen. is established to accommodate both species.

Global habitat suitability modeling reveals insufficient habitat protection for mangrove crabs.

Mangrove crabs are important components of mangrove forests however their large scale habitat suitability and conservation received little attention. The Metopograpsus thukuhar/cannicci species complex is a mangrove dwelling species occurs in the Indo-Pacific mangrove forests. Since identifying the complex suitable habitat is critical for its conservation, we modeled global habitat suitability of the complex within marine biogeographic realms and estimated representation of the complex suitable habitats within marine protected areas. We found that the complex' largest and smallest suitable ranges are located in Central Indo-Pacific and Temperate Southern Africa realms, respectively. Only 12.5% of the complex suitable habitat is protected. The highest proportion of the complex' protected suitable habitat (22.9%) is located in Western Indo-Pacific realm while the lowest proportion of the complex' protected suitable habitat (1.38%) is located in Central Indo-Pacific realm. Suitable unprotected habitats of the complex identified in this study have high priority for conservation and should be included in marine protected areas to ensure species conservation. Our results show that species distribution models are practical tools to study marine species distribution across large spatial scales and help marine conservation planning.

Redescription of Arcotheres tivelae (Gordon, 1936), a pea crab endemic to the Persian Gulf and Gulf of Oman (Crustacea: Decapoda: Brachyura: Pinnotheridae).

The taxonomy of the pinnotherid crab, Pinnotheres tivelae (Gordon, 1936), now assigned to Arcotheres Manning, 1993, is revised. Type specimens from Muscat, Gulf of Oman, are compared with extensive material from the type locality and Persian Gulf. Arcotheres tivelae is shown to be a valid species, is redescribed, figured to modern standards and males are reported for the first time. This species had been confused with A. placunae (Hornell Southwell, 1909) from Pakistan and western India, but the two species can be distinguished by the morphology of the carapace, third maxilliped, ambulatory leg features and characters of the male first gonopod. Arcotheres tivelae is morphologically closest to three other species also found in venerid clams, A. exiguus (Brger, 1895), A. rayi Ahyong Ng, 2007, and A. obesus (Dana, 1852), but the distal morphology of its male first gonopod is distinct from its congeners. Furthermore, A. tivelae is recorded from Kuwait for the first time.

A new species of Galene de Haan, 1833 (Galenidae: Brachyura) from the middle Miocene of Zagros Mountains, Iran.

A new species of Galene de Haan, 1833 (Decapoda: Brachyura: Galenidae) is described from the Mid Miocene (Langhian) strata of the Mishan Formation exposed at two localities in Hormozgan Province, Zagros Mountains, Iran. The galenid species, Galene dashtbani n. sp. is considered as the oldest representative of the genus and simultaneously the westernmost occurrence of all fossil and extant congeners known to date. The genus is currently limited to the Indo-West Pacific region. The present fossil occurrence of the genus suggests a Tethyan origin and subsequent migration eastward.

A new sponge-dwelling species of Synalpheus Spence Bate, 1888 (Decapoda: Caridea: Alpheidae) from the Persian Gulf.

The present study is based on material collected in the intertidal and shallow subtidal areas of two Islands in the Persian Gulf, Abu-Musa and Larak. The new species, Synalpheus pentaspinosus n. sp., is closely related to S. quinquedens Tattersall, 1921. These two species share a very characteristic, sixth pleonite armed posteriorly with five stout sharp teeth, a feature unique within the genus. The color of ovaries or freshly laid eggs, red-orange in S. pentaspinosus n. sp. vs. green in S. quinquedens, is the most obvious character, by which the new species may be distinguished from S. quinquedens in the field. In addition, the two species can be separated by two characters on the dactylus of the minor cheliped. In the new species, the dactylus is furnished with two prominent rows of setae, one dorsally and one mesially, and has a small concavity on the cutting edge, contrasting to only one mesial row of setae and no obvious concavity in S. quinquedens.

A new species and a new record of alpheid shrimps of the genus Salmoneus Holthuis, 1955 (Crustacea: Decapoda: Alpheidae) from Iran.

Extensive samplings of benthic fauna along the Iranian coastlines of the Persian Gulf and Gulf of Oman during 2018-2019 resulted in a small series of shrimps of the alpheid genus Salmoneus. Based on a thorough examination of this material, as well as previously collected specimens, one new species, S. rashedi n. sp., is described, whilst a significant range extension of S. chadwickae Duris Horká, 2016 is reported. Salmoneus rashedi n. sp. is a member of S. gracilipes species group. The present new species differs from other species of the group by a longer rostrum with a short dorsal crest and a single ventral rostral tooth; the species occurs in two colour forms from yellow to reddish orange with some transverse red bands.

An updated checklist of caridean shrimps of the Persian Gulf and Gulf of Oman.

The material of the present checklist has been collected from the Iranian intertidal and shallow subtidal shores of the Persian Gulf and Gulf of Oman from 2015 to 2019, in addition to re-examining all the materials deposited in the Zoological Museum of the University of Tehran. This checklist providing 16 new records for the Persian Gulf and 15 for the Gulf of Oman raised the number of recorded caridean shrimps to 109 and 49 for these gulfs, respectively. However, the actual number of these shrimps are higher than these numbers due to two facts. Firstly, most of the subtidal diverse ecosystems, e.g. coral reefs and seagrass bed have not been seriously investigated taxonomically. Secondly, there are some members of species complexes and probably some new species in the study which need to be carefully treated.

Phylogeography of Potamon ibericum (Brachyura: Potamidae) identifies Quaternary glacial refugia within the Caucasus biodiversity hot spot.

Refugia are critical for the maintenance of biodiversity during the periods of Quaternary climatic oscillations. The long-term persistence of refugial populations in a large continuous refugium has resulted in a homogenous pattern of genetic structure among populations, while highly structured evolutionary lineages characterize the restriction of refugial populations to smaller subrefugia. These mechanisms have resulted in the identification of hot spots of biodiversity within putative glacial refugia. We studied phylogeography of Potamon ibericum (Brachyura: Potamidae) in the drainages of the western Caucasus biodiversity hot spot (i.e., Colchis and the Caucasus) to infer spatial genetic structure and potential refugia for a freshwater crab in this region. These areas have traditionally considered as a refugium due to the presence of Tertiary relict species. We integrated population genetic data and historical demographic analysis from cytochrome oxidase subunit I sequences and paleoclimatic data from species distribution modeling (SDM). The results revealed the lack of phylogeographic structure and provided evidence for demographic expansion. The SDM presented a rather homogenous and large refugium that extended from northeast Turkey to Colchis during the last glacial period. In contrast to these findings, previous phylogeographic study on P. ibericum of the eastern Caucasus biodiversity hot spot (i.e., Hyrcania) identified multiple independent refugia. By combining these results, we explain the significance of this important western Palearctic hot spot of biological diversity in shaping the geographic distribution of intraspecific genetic diversity in a freshwater taxon.

Annotated checklist of the snapping shrimps of the genus Alpheus Fabricius, 1798 (Crustacea: Decapoda: Alpheidae) from the Persian Gulf and Gulf of Oman, Iran.

In the present study, shrimps belonging to the genus Alpheus from the Persian Gulf and Gulf of Oman are documented based on the existing literature and extensive new sampling from 2013 to 2018 along the Iranian coast. A total of 35 species are recorded from the region, of which 40% (14 species) and 60% (21 species) are new records for the Persian Gulf and Gulf of Oman, respectively. Among 19 sampling localities, A. lobidens De Haan, 1849, A. edwardsii (Audouin, 1826) and A. edamensis De Man, 1888 occurred in 14, 13 and 9 localities, respectively. Among the visited habitats, 14 species (40%) were associated with coral or other sessile invertebrates, 13 species (37%) were collected on sandy or rocky substrates, five species (14%) were obtained from muddy substrates, and three species (9%) were found associated with goby fishes. Among Alpheus species, three (10%) were endemic to the Persian Gulf. Most taxa show affinities to both western Indian Ocean and East Indian/West Pacific Oceans.

Annotated checklist of the decapod crustaceans of the Gulf of Oman, northwestern Indian Ocean.

The decapod crustaceans of the Gulf of Oman have been documented based on the published literature and new sampling along the Iranian coast between 2005 and 2015. A total of 121 species were collected along the Iranian coast, of which 43 are new records for the Gulf of Oman. The Decapoda of the Gulf is currently represented by 258 species belonging to five infraorders: Axiidea, Achelata, Anomura, Brachyura, and Caridea. Brachyura, with 176 species, are the best represented group, followed by Anomura and Caridea with 42 and 17 species, respectively. The least diverse groups are Achelata, with five species, and Axiidea, with three. On the basis of the available information, the northern (Iranian) coast with 189 species is more diverse than the southern (United Arab Emirates and Oman) coast with 134 species.

Atarbolana makranensis, a new species of Cirolanidae (Crustacea, Isopoda) from Makran, Iranian coast of the Gulf of Oman.

Atarbolana makranensis sp. n. is described from the intertidal zone of Makran along the Iranian coast of the Gulf of Oman. Atarbolana makranensis sp. n. can be recognized by the presence of a tuft of long setae on the antennal flagellum of males, elongate pleotelson with 12 robust marginal setae, pleotelson with narrowly rounded apex extending well beyond the uropodal endopod, uropodal endopod half as long as exopod with 14 robust marginal setae, and appendix masculina with an acute apex and extending beyond endopod distal margin. A key is provided for the four known species of Atarbolana Bruce & Javed, 1987.

Two new species of Palapedia Ng, 1993 (Crustacea, Decapoda, Brachyura,Xanthidae) from the Persian Gulf.

Two new species of Palapedia Ng, 1993, are described based on material collected from Abu-Musa Island, Persian Gulf during the present study, from Bahrain by the 1937/38 Danish Expedition, and from the Saudi Arabian coast of the Persian Gulf by Michael Apel in 1992-1995. Palapedia persica n. sp. is distinguishable from its congeners by having distinctly large denticles on the upper margin of the palm and fingers of the chelae and anterior margin of the ambulatory dactyli, and by the markedly sickle-shaped dactylus of the ambulatory legs. Palapedia apeli n. sp. is similar to P. valentini Ng, 1993, and P. nitida (Stimpson, 1858), by having relatively smooth appendages.

A new species of decorator crabs, genus Menaethiops Alcock, 1895 (Crustacea: Decapoda: Brachyura: Majoidea: Epialthidae), from Abu-Musa Island, Persian Gulf, Iran.

Menaethiops abumusa n. sp. is closely similar to M. bicornis Alcock, 1985, and M. gadaniensis Kazmi & Tirmizi, 1999, regarding the relatively contiguous rostral spines. The new species is easily distinguishable from its two congeners by having distinctly round angles of orbital eaves and distally divergent rostral spines. Whereas in M. bicornis, and M. gadaniensis, the angles of orbital eaves are anteriorly produced and rostral spines are closely attached to each other along their entire length.  Other morphological differences include the carapace spination/granulation, basal antennal segments, and morphology of the male's first gonopod. Menaethiops gadaniensis was described from Gadani, Pakistan and was only known from the type locality, but is here recorded for the first time from the Gulf of Oman.

A new species of porcelain crab, Petrolisthes tuerkayi n. sp. (Crustacea: Anomura: Porcellanidae), from the Persian Gulf.

A new species of porcellanid crab, Petrolisthes tuerkayi n. sp., is described from the Persian Gulf. The new species is closely related to P. rufescens Heller, 1861, but is easily distinguishable by having three or four large spines distally on the posterior margin of the carpus of chelipeds, whereas the posterior margin of the cheliped merus in P. rufescens is unarmed.

A checklist of the barnacles (Crustacea: Cirripedia: Thoracica) of the Persian Gulf and Gulf of Oman with nine new records.

The present annotated checklist contains 43 species of thoracican barnacles known to date from the area, 33 and 26 from the Persian Gulf and the Gulf of Oman, respectively. Nine species are new records for the area including Amphibalunus subalbidus (Henry, 1973), Armatobalanus allium (Darwin, 1854), Chelonibia patula (Ranzani, 1818), Conchoderma hunteri (Owen, 1830), Lepas anserifera Linnaeus, 1767, Lithotrya valentiana Reinhardt, 1850, Megabalanus coccopoma (Darwin, 1854), Megabalanus occator (Darwin, 1854) and Platylepas hexastylos (Fabricius, 1798), of which A. subalbidus and M. coccopoma are reported as alien species from the region.