A distinctive new species of the genus Polyonyx Stimpson, 1858 (Crustacea: Decapoda: Anomura: Porcellanidae) from Okinawa, southwestern Japan

The new porcellanid crab Polyonyx deezi n. sp. is described on the basis of two specimens from Okinawa Island, Ryukyu Islands, southwestern Japan. The new species belongs to the P. sinensis group and may be closest to P. socialis Werding & Hiller, 2019 in the comparatively broad proportions of the carpi of the chelipeds and meri of the ambulatory legs. However, P. deezi n. sp. is immediately distinguished from all other congeners by the median branchial margins of the carapace being bluntly angular and produced laterally and the dorsal surfaces of the carapace and chelipeds with distinct protuberances. The occurrence of P. deezi n. sp. from coral reefs may be unusual in species of the P. sinensis group because many of the known species have been recorded from estuaries or coastal embayments. An identification key to the Indo-West Pacific species of the Polyonyx sinensis group is provided.

Gracilaria parva sp. nov. (Gracilariales, Rhodophyta) a Diminutive Species from the Tropical Eastern Pacific

DNA sequencing of the plastid encoded rbcL gene supported by morpho-anatomical features reveals Gracilaria parva sp. nov. from Panama and Ecuador in the tropical eastern Pacific Ocean. In the rbcL phylogram, G. parva occurs in a clade sister to the western Atlantic species G. galatensis. Morphologically and anatomically, G. parva is distinguished from two similar, described tropical eastern Pacific species, G. brevis and G. veleroae by its small size, to 2.5 cm tall with branch widths mostly <2 mm occasionally to 4 mm, and by its two to three cell layered cortex. Gracilaria brevis and G. veleroae are taller, have wider branches, and a one cell layered cortex. DNA sequencing is needed to resolve the many diminutive species in the tropical eastern Pacific, particularly those occurring in turf communities. DNA sequencing of historical type specimens from the 19th and 20th centuries is also needed to correctly apply names in this region.

Biology, ecology and management perspectives of overexploited deposit-feeders sea cucumbers, with focus on Holothuria tubulosa (Gmelin, 1788)

The increasing harvesting of low trophic level organisms is rising concern about the possible consequences on the ecosystem functioning. In particular, the continuous demand of sea cucumbers from the international market lead to the overexploitation of either traditionally harvested and new target species, including the Mediterranean ones. Sea cucumbers are mostly deposit feeders able to consume sedimentary organic matter and, thus, are ideal candidate for the remediation of eutrophicated sediments, like those beneath aquaculture plants. Breeding and restocking of overexploited sea cucumbers populations are well established practice for Indo-Pacific species like Holothuria scabra and Apostichopus japonicus. Some attempts have been also made for the Mediterranean species Holothuria tubulosa, but, so far, the adaptation of protocols used for other species presented several issues. We here summarize narratively the available information about sea cucumbers rearing protocols with the aim of identifying their major flaws and gaps of knowledge and fostering research about new triggers for spawning and feasible protocols to reduce the high mortality of post-settlers.

On two new species of deep-sea carrier crabs (Crustacea, Brachyura, Homolodromiidae, Dicranodromia) from Taiwan and the Philippines, with notes on other Indo-West Pacific species

The systematics of four species of the homolodromiid genus Dicranodromia A. Milne-Edwards, 1880, from East Asia and the Philippines is reappraised: D. danielae Ng &amp; McLay, 2005, D. doederleini Ortmann, 1892, D. karubar Guinot, 1993, and D. martini Guinot, 1995; and key characters such as the epistome, gonopods, and spermatheca are figured in detail. Two new species, D. erinaceussp. nov. and D. robustasp. nov., are described from Taiwan and the Philippines, respectively. Dicranodromia erinaceussp. nov. resembles D. spinulata Guinot, 1995, and D. delli Ahyong, 2008 (from New Caledonia and New Zealand) but can be separated by its distinctly spinulated carapace surfaces and proportionately shorter fifth ambulatory legs. Dicranodromia robustasp. nov. is superficially similar to D. baffini (Alcock &amp; Anderson, 1899) and D. karubar Guinot, 1993, but can easily be separated by possessing a broad dorsoventrally flattened infraorbital tooth. A genetic study of the species using the mitochondrial cytochrome c oxidase I gene confirms that the taxa are distinct, with D. erinaceussp. nov. coming out in a well-supported clade from congeners. The megalopa of D. doederleini is also reported for the first time.

The “Cribrilina annulata" problem and new species of Juxtacribrilina (Bryozoa: Cheilostomata: Cribrilinidae) from the North Pacific

Originally described from Greenland, Juxtacribrilina annulata (Fabricius, 1780) (previously known as Cribrilina annulata) has long been regarded as having a circumpolar, Arctic-boreal distribution. The genus Juxtacribrilina Yang, Seo, Min, Grischenko & Gordon, 2018 accommodated J. annulata and three related North Pacific species formerly in Cribrilina Gray, 1848 that lack avicularia, have a reduced (hood-like, cap-like, or vestigial) ooecium closely associated with modified latero-oral spines to form an ooecial complex, and produce frontally or marginally positioned dwarf ovicellate zooids. While the recently described NW Pacific species J. mutabilis and J. flavomaris, which have a vestigial ooecium like a short, flattened spine, clearly differ from J. annulata, the differences between J. annulata and other Pacific populations remained unclear. Here we provide descriptions for five species from the North Pacific region. We identified a specimen from the Sea of Okhotsk as J. annulata. Among the other four species, J. ezoensis n. sp. has a trans-Pacific distribution (abundant at Akkeshi, Hokkaido, Japan; also detected in the Commander Islands and at Ketchikan, Southeast Alaska); J. pushkini n. sp. was found only at Ketchikan; J. dobrovolskii n. sp. was found only at Shikotan Island in the Lesser Kuril Chain; and J. tumida n. sp. was found only at Kodiak, Gulf of Alaska. These four species all differ from J. annulata in having one or two frontal pore chambers on the proximal gymnocyst of most zooids; in budding frontal dwarf ovicellate zooids from these chambers rather than from basal pore chambers; in producing dwarf zooids more abundantly; and in having ooecia that are somewhat to markedly more reduced (cap-like rather than hood-like) and more closely integrated with the modified latero-oral spines. Furthermore, in the Pacific species, the ooecium in basal zooids arises from the roof of the distal pore chamber of the maternal zooid; ovicellate zooids can thus also bud a distal autozooid and are often arranged in columnar series with other zooids. In J. annulata, the hood-like kenozooidal ooecium budded from the maternal zooid replaces the distal autozooid, and ovicellate zooids are thus usually not embedded in a columnar series.

Mitochondrial genome announcements need to consider existing short sequences from closely related species to prevent taxonomic errors

The reconstruction of complete mitochondrial genomes (mitogenomes) has considerable potential to clarify species relationships in cases where morphological analysis and DNA sequencing of individual genes are inconclusive. However, the trend to use only mitogenomes for the phylogenies presented in mitogenome announcements carries the inherent risk that the study species’ taxonomy is incorrect because no mitogenomes have yet been reconstructed for its sister species. Here, I illustrate this problem using the mitogenomes of two seahorses, Hippocampus capensis and H. queenslandicus. Both specimens used for mitogenome reconstruction originated from traditional Chinese medicine markets rather than native habitats. Although mitogenome phylogenies placed these specimens correctly among the seahorses from which mitogenomes were available at the time, incorporating single-marker sequence from closely related species into the phylogenies revealed that both mitogenomes are problematic. The mitogenome of the endemic South African H. capensis did not cluster among single-marker DNA sequences of seahorses from the species’ native habitat, but among sequences submitted under the names H. casscsio, H. fuscus and H. kuda that originated from all over the Indo-Pacific, including China. Phylogenetic placement of the mitogenome of H. queenslandicus within a cluster of seahorses that also included H. spinosissimus confirms an earlier finding that H. queenslandicus is a synonym of H. spinosissimus, a widespread Indo-Pacific species that also occurs in China. It is recommended that mitogenome announcements incorporate available single-marker sequences of closely related species, not only mitogenomes. The reconstruction of mitogenomes can exacerbate taxonomic confusion if existing information is ignored.

Redescription of Gnorimosphaeroma oregonense (Dana, 1853) (Crustacea, Isopoda, Sphaeromatidae), designation of neotype, and 16S-rDNA molecular phylogeny of the north-eastern Pacific species

Gnorimosphaeroma oregonense (Dana, 1852) is revised, a male neotype is designated, photographed, and illustrated; the species occurs from Vancouver British Columbia to the central California coast. 16S-rDNA sequences (~650 bp) for all available ethanol preserved species of Gnorimosphaeroma were used to hypothesize their relationships. Our analyses revealed a sister taxon relationship between the fully marine G. oregonense and the brackish to freshwater species, G. noblei. The oyster associated and introduced G. rayi is sister to a previously not recognized or identified, but genetically distinct, Gnorimosphaeroma sp. collected at two sites in San Francisco Bay. Gnorimosphaeroma sp. is probably also a western Pacific species based on its genetic relationship to G. rayi. Photographic comparisons are offered for G. oregonense (marine), G. noblei (freshwater), G. rayi (introduced), G. sp. (presumably introduced), and G. insulare (San Nicolas Island). Records of the holdings at the Los Angeles County Museum of Natural History are summarized. Without material available north of Vancouver through Alaska, the range of G. oregonense could not be genetically verified. This review includes a diagnosis and description of the genus Gnorimosphaeroma Menzies, 1954.

First records of the bandfin scorpionfish, Scorpaenopsis vittapinna (Actinopterygii, Scorpaeniformes, Scorpaenidae), from Australia

Seven specimens (15.6–43.5 mm standard length) of Scorpaenopsis vittapinna Randall et Eschmeyer, 2002 (Scorpaenidae), a widely distributed Indo-West Pacific species, are recorded from Australian waters for the first time. A full description of the specimens is given, and intraspecific variations in comparison with the type specimens are noted.

Diversity of intertidal, epibiotic, and fouling barnacles (Cirripedia, Thoracica) from Gujarat, northwest India

The present work studied the diversity of intertidal, epibiotic, and fouling barnacles in the state of Gujarat, northwest India. In total, eleven species belonging to eight genera and five families were recorded in the present study. The Arabian intertidal species Tetraclita ehsani Shahdadi, Chan &amp; Sari, 2011 and Chthamalus barnesi Achituv &amp; Safriel, 1980 are common in the high- and mid-intertidal rocky shores of Gujarat suggesting that the Gujarat barnacle assemblages are similar to the assemblages in the Gulf of Oman Ecoregion. The biogeographical boundary between the Gulf of Oman and Western Indian ecoregions for barnacles should probably extend southward towards the waters adjacent to Mumbai, where Indo-Pacific species of intertidal barnacles dominate. This study provides the first reports of the common widely distributed balanomorph barnacles Striatobalanus tenuis (Hoek, 1883), Tetraclitella karandei Ross, 1971, Amphibalanus reticulatus (Utinomi, 1967), and lepadid barnacle Lepas anatifera Linnaeus, 1758 in Gujarat, as well as of the chthamalid barnacle Chthamalus barnesi in India.