[Invertebrate • 2025] Acanthotrochus verruciosseous • A New abyssal Species of Acanthotrochus (Holothuroidea: Apodida) from the Aleutian Trench, North Pacific Ocean

 

 Acanthotrochus verruciosseous

Ogawa, Chen & Sigwart, 2025

DOI: doi.org/10.5343/bms.2025.0092 

 x.com/squamiferum

 

A new species of the rarely seen myriotrochid holothurian genus Acanthotrochus, Acanthotrochus verruciosseous sp. nov., is described from 5272 to 5325 m deep in the Aleutian Trench, North Pacific Ocean. The new species is morphologically clearly separated from three valid congeners based on acanthotrochid-type wheel ossicles bearing multiple low knobs on the inner and outer rims as well as the outward teeth. The outer, concave side of the acanthotrochid-type wheels also form inward-pointing protrusions at the base of spokes at the inner rim edge. These ossicle features have never been observed in the three described species. Acanthotrochus has a global distribution, in the North Atlantic, Indian Ocean, and Antarctica, with a maximum depth of 3320 m. Our discovery is the first record of Acanthotrochus from the North Pacific and from the lower abyssal zone, which greatly extends the known geographic and bathymetric range of Acanthotrochus. Partial mitochondrial 16S ribosomal DNA sequences from the type specimens of A. verruciosseous sp. nov. are clearly separated from the type species of the genus, Acanthotrochus mirabilis Danielssen and Koren, 1881.

Acanthotrochus verruciosseous sp. nov.

 Ogawa, Akito; Chen, Chong and Sigwart, Julia D. 2025. A New abyssal Species of Acanthotrochus (Holothuroidea: Apodida) from the Aleutian Trench, North Pacific Ocean. Bulletin of Marine Science. DOI: doi.org/10.5343/bms.2025.0092 

 x.com/squamiferum/status/2001017902213079083

[Invertebrate • 2025] Breviturma securis • A New brittle star of the Genus Breviturma (Ophiuroidea: Ophiocomidae), with a new record from Taiwan

Breviturma securis 

 Chang & Shih, 2025 

DOI: doi.org/10.5852/ejt.2025.997.2919 

 facebook.com/HsiTeSHIH

Abstract

The genus Breviturma, a group of brittle stars inhabiting intertidal and shallow subtidal zones, includes eight recognized species distributed mainly across the Indo-West Pacific. This study describes a new species, Breviturma securis sp. nov., from Taiwan. The new species is distinguishable from its congeners through both morphological and molecular evidence, including disc granule density, arm spine sequences, and distinctive color patterns on the dorsal disc and dorsal arm plates. Phylogenetic analyses based on 16S rRNA and COI genes support its unique status, revealing interspecific divergence distances of 18.27–26.66% between B. securis and other congeners in the Indo-West Pacific. Based on the distribution patterns of its congeners, B. securis is expected to be widely distributed in other regions of the Indo-West Pacific. A newly recorded species, Breviturma krohi (Stöhr, Boissin & Hoareau, 2013), from Taiwan is also reported.

Keywords: Breviturma securis sp. nov., Breviturma krohi, East Asia, 16S rDNA, cytochrome c oxidase subunit I (COI)

Breviturma securis sp. nov.
A–F. In situ.A–D. Adults.E–F. Juveniles.G–H. A specimen(NCHUZOOL 17241) with a parasitic snail (Eulimidae sp.) attached at the base of an arm. G. Ventral view. H. Dorsal view.

Breviturma securis sp. nov.

Etymology: The species name securis is derived from the Latin word meaning ‘axe’, referencing the axe-shaped dark patterns on the dorsal arm plates. The name is used as a noun in apposition.

Kai Chang and Hsi-Te Shih. 2025. Description of A New brittle star of the Genus Breviturma (Ophiuroidea: Ophiocomidae), with a new record from Taiwan. European Journal of Taxonomy. 997(1); 28–50. DOI: doi.org/10.5852/ejt.2025.997.2919

  facebook.com/HsiTeSHIH/posts/10236799703918661

[Invertebrate • 2024] Synallactes mcdanieli • A New Species of Sea Cucumber (Holothuroidea: Synallactida) from British Columbia, Canada and the Gulf of Alaska, USA

Synallactes mcdanieli 

Marín, Ochoa & Conejeros-Vargas, 2024

DOI: doi.org/10.3897/BDJ.12.e124603

Abstract

Background: The family Synallactidae comprises mostly deep-sea forms and is the least-studied large taxon amongst deep-sea cucumbers. They are part of the abyssal megafauna and play an important role in modifying the sediment landscape and structuring the communities that live within it. The family embraces the genus Synallactes, which contains approximately twenty-five species from the Pacific, Atlantic (six species), Indian (seven species) and Antarctic Oceans (one species).

New information: Synallactes mcdanieli sp. nov. is described from the Northeast Pacific, Knight Inlet, British Columbia, Canada to Kodiak Island, Gulf of Alaska, USA, at depths from 21 to 438 m. This new species is unique amongst the species of the genus Synallactes because of the number and arrangement of dorsal papillae, number of Polian vesicles, together with the entire ossicle arrangement. In addition, this species has the shallowest bathymetric distribution ever recorded for this genus.

Keywords: Synallactidae, taxonomy, Northeast Pacific

Synallactes mcdanieli sp. nov. In situ specimens at Battery Point, near Haines Alaska, USA, photo by Neil McDaniel. Approximately TL of specimens ~ 250-300 mm.

 

 Francisco A Solís Marín, Andrea A Caballero Ochoa and Carlos A Conejeros-Vargas. 2024. Synallactes mcdanieli sp. nov., A New Species of Sea Cucumber from British Columbia, Canada and the Gulf of Alaska, USA (Holothuroidea, Synallactida). Biodiversity Data Journal. 12: e124603. DOI: doi.org/10.3897/BDJ.12.e124603

[Invertebrate • 2024] Nesometra integra • A New Species of Feather Star (Echinodermata: Crinoidea: Comatulida: Antedonidae) from Southern Japan and Western Australia

 

Nesometra integra 

Pratama, Virgili, Reimer & Fujita, 2024 

 

カンゼンセソコヒメウミシダ  ||  DOI 10.12782/specdiv.29.255

Abstract

A new species of the genus Nesometra Virgili, Poliseno, Fujita, Pratama, Fernández-Silva, and Reimer, 2023 is described based on the specimens collected from the Amami Islands and Ogasawara Islands, Japan and Cunningham Island, Australia. Nesometra integra n. sp. is distinguished from its single congener, N. sesokonis (Obuchi, Kogo, and Fujita, 2009), by having complete proximal pinnulation and cirri with reduced medial constriction on its distal part.

Keywords: Antedonidae, Nesometra, new species, Japan, Australia, coral reef

Nesometra integra n. sp., external morphology, holotype (A–D, F: NSMT E-14402), paratype (E: NSMT E-14405).
A, Whole body, in seawater, oral view; B, schematic drawing of proximal ossicles and pinnulation, aboral view; C, close up of arm, aboral view; D, longer (left) and shorter (right) cirri, lateral view; E, first division series with first two brachials of two arms, aboral view; F, pinnules, lateral view.

Abbreviations: br1–br12, first to twelfth brachials of arm; c1–c4, first to fourth cirrals; CD, centrodorsal; IBr, first division series; Ibr1, first brachial of first division series; Ibr2ax, second brachial (axillary) of first division series; P1–P5, first to fifth exterior pinnule; Pa–Pd, first to fourth interior pinnule; PD, distal pinnule; PM, middle pinnule; p1–p5, first to fifth pinnulars; R, radial; tc, terminal claw. Orientation: Pr, proximal; Di, distal. Scale bars: A, 5mm; C–F, 1mm.

Living specimens of Nesometra integra n. sp. showing variation of coloration pattern. In situ photographs on the bottom of a coral rubble rock in Amami-Ohshima Island.
A, Paratype (NSMT E-13603), solid coloration; B, paratype (NSMT E-13604), dotted coloration.

Family Antedonidae Norman, 1865 

Subfamily Antedoninae Norman, 1865 

Genus Nesometra Virgili, Poliseno, Fujita, Pratama, Fernández-Silva, and Reimer, 2023 

[New Japanese name: Sesoko-hime-umishida-zoku] 

Nesometra integra n. sp. 

[New Japanese name: Kanzen-sesoko-hime-umishida] (Figs 1, 3–7, 9A, B)

Distribution. Japan (Ogasawara Islands and Amami Islands) and Australia (Cunningham Island). Bathymetrical range: 17.5–110m; 52–54m in the Ogasawara Islands, 17.5– 75m in the Amami Islands, 110m in Cunningham Island. 

Etymology. The specific name, integra (Latin adjective, feminine), means ‘complete’ after the adult complete proximal pinnulation of the new species compared to its congener, N. sesokonis. 

The Japanese name of the genus Nesometra, Sesoko-himeumishida-zoku (セソコヒメウミシダ属) is derived from Sesoko (瀬底), the type locality of the type species N. sesokonis, and hime-umishida-zoku (ヒメウミシダ属), the Japanese name of antedonid comatulids and the Japanese word for genus, zoku (属). The Japanese name of the new species, Kanzen-sesokohime-umishida (カンゼンセソコヒメウミシダ), is derived from kanzen (完全), means also ‘complete’ as a translation of the specific name, integra.

 

Gregorius A. Pratama, Riccardo Virgili, James D. Reimer and Toshihiko Fujita. 2024. Nesometra integra, A New Species of Feather Star (Echinodermata: Crinoidea: Comatulida: Antedonidae) from Southern Japan and Western Australia. Species Diversity. 29(2); 255-268. DOI doi.org/10.12782/specdiv.29.255

https://www.jstage.jst.go.jp/article/specdiv/29/2/29_SD23-38/_article

Researchgate.net/publication/383342175_Nesometra_integra_a_New_Species_of_Crinoidea_Japan_and_Australia

[Mollusca • 2024] Brachiomya ducentiunus • Bivalves of Superfamily Galeommatoidea (Bivalvia) from western South Africa, with Observations on Commensal Relationships and Habitats

Brachiomya ducentiunus 

Valentich-Scott, Griffiths, Landschoff, R. Li & J. Li, 2024. 

DOI: 10.3897/zookeys.1207.124517

Abstract

The Galeommatoidea are a diverse but little-studied group of small bivalves, well known for the symbiotic relationships many species have with a range of invertebrate taxa. Four species collected from the Western Cape region of South Africa were examined and illustrated, providing new details on their habitat preferences, and depicting the mantle structure of live specimens for the first time. Brachiomya ducentiunus sp. nov., is described herein, and an additional record of Montacuta substriata (Montagu, 1808) is reported from South Africa. Brachiomya ducentiunus and Montacuta substriata have obligate symbiotic relationships with different burrowing echinoids, while Kellia becki (WH Turton, 1932) and Melliteryx mactroides (Hanley, 1857) are free-living. DNA data and phylogenetic analyses are provided for three of the species.

Key words: Biodiversity, commensalism, heart urchin, South Atlantic Ocean, Spatagobrissus mirabilis, Spatangus capensis, symbiosis, taxonomy

 

Brachiomya ducentiunus new species, living animals
A, B crawling on hard substrate C overview of specimens crawling on the aboral surface of urchin Spatagobrissus mirabilis D crawling on urchin spine with mantle and foot extended E, F extended mantle between urchin spines.

Brachiomya ducentiunus sp. nov.

Discovery: Initially discovered via free-diving in 2016 at the type locality, collected by Jannes Landschoff and Craig Foster.

Etymology: The name ducentiunus is from Latin, meaning “201.” The species was discovered while preparing and working on the ‘1001 Seaforest Species’ project, a research and storytelling program aimed at increasing awareness of regional kelp bed ecosystems colloquially referred to as ‘the Great African Seaforest’ (see www.seachangeproject.com). The number 201 was chosen as a unique identifier for the 1001 program, with the goal to link each hundredths species to a species described as new to science.

Comparisons: The Pacific and Asian Brachiomya stigmatica, which is the only other known species in the genus, is more evenly rounded anteriorly, has a strong rust-colored stripe medially, lacks radial striae, and has more developed teeth.

Paul Valentich-Scott, Charles Griffiths, Jannes Landschoff, Ruiqi Li, Jingchun Li. 2024. 

Bivalves of Superfamily Galeommatoidea (Mollusca, Bivalvia) from western South Africa, with Observations on Commensal Relationships and Habitats. ZooKeys. 1207: 301-323. DOI: doi.org/10.3897/zookeys.1207.124517

[Paleontology • 2023] Krommaster spinosus • Earliest Known ophiuroids (Ophiuroidea: Encrinasteridae) from high Palaeolatitude, southern Gondwana, recovered from the Pragian to earliest Emsian Baviaanskloof Formation (Table Mountain Group, Cape Supergroup) South Africa

Krommaster spinosus

Reddy, Thuy, Reid & Gess, 2023

 

DOI: 10.1371/journal.pone.0292636

Abstract

For the first time, ophiuroids have been found in South African strata predating the lowermost Bokkeveld Group. These comprise natural moulds and casts from two localities in the ‘upper unit’ of the Baviaanskloof Formation (Table Mountain Group). As a Pragian to earliest Emsian age has been inferred for this member, the new taxa comprise the earliest high-palaeolatitude ophiuroid records from southern Gondwana. Morphological analysis of the specimens revealed the presence of two distinct taxa. One is here described as Krommaster spinosus gen. et sp. nov., a new encrinasterid characterised by very large spines on the dorsal side of the disc, the ventral interradial marginal plates and the arm midlines. The second taxon is a poorly preserved specimen of Hexuraster weitzi, a cheiropterasterid previously described from the slightly younger Bokkeveld Group.

 

   

Krommaster from the Baviaanskloof Formation, Upper Unit, Cape Supergroup, Table Mountain Group, Eastern Cape South Africa paratypes.
 A- part aboral view (AM18224) with disk scales preserved, B- counterpart with holes, which comprise moulds of spines (image reversed) (AM18224A), C- silicone peel of the oral view (AM18221). Abbreviations; PS: periradial suture.

Systematic palaeontology

Class– OPHIUROIDEA Gray, 1840  

Order– OEGOPHIUROIDEA Matsumoto, 1915 

Suborder– LYSOPHIURINA Gregory, 1897  

Family– ENCRINASTERIDAE Schuchert, 1914  

Subfamily– ENCRINASTERINAE Schuchert, 1914  

Krommaster gen. nov.

Diagnosis—Moderately large encrinasterid with disk covered by a mosaic of small, thin scales and extending to the 5th or 6th arm segment; interradii bound by relatively small marginal plates except for a single larger plate bearing a single very large, conical, pointed spine; similar but slightly smaller spines on dorsal disk and along the dorsal midline of the arms; ambulacrals with a very sharp transverse furrow close to the distal edge of the leg of the boot; adambulacral plates with two to three relatively large, short, conical, pointed lateral arm spines.

Etmology—‘Kromm’ From Kromme River, in the canyon of which the ophiuroid lag deposit was recovered. Krom is the Afrikaans word for curve. ‘Aster’, latin meaning star.

Krommaster spinosus sp. nov.

 Etymology—‘spinosus’, latin for spiny or spiky, referring to the presence of large spines on the central disk and arms.

Type locality and stratum—Early Devonian, Pragian to earliest Emsian, ‘upper unit,’ Baviaanskloof Formation, Table Mountain Group, Cape Supergroup, Eastern Cape, South Africa.

  Caitlin Reddy, Ben Thuy, Mhairi Reid and Robert Gess. 2023. Earliest known ophiuroids from high palaeolatitude, southern Gondwana, recovered from the Pragian to earliest Emsian Baviaanskloof Formation (Table Mountain Group, Cape Supergroup) South Africa. PLoS ONE. 18(10): e0292636. DOI: 10.1371/journal.pone.0292636

 phys.org/news/2023-11-oldest-samples-brittle-stars-supercontinent.html

[Invertebrate • 2024] Oneirophanta brunneannulata, O. idsseica & O. lucerna • Three New Species and One New Record of Deimatidae (Echinodermata: Holothuroidea: Synallactida) discovered in the South China Sea and the Mariana Fore-arc Area using integrative taxonomic methods

  

Oneirophanta lucerna  
 Oneirophanta brunneannulata  

Xiao & Zhang, 2024

DOI: 10.3897/zookeys.1195.115913

Abstract

Deep-sea holothurian specimens were collected during five scientific expeditions (2018–2023) using the submersible vehicle ‘Shenhaiyongshi’. Our examination of specimens of Deimatidae from the South China Sea and the Mariana fore-arc area revealed three new species, which were described as Oneirophanta idsseica sp. nov., Oneirophanta brunneannulata sp. nov., and Oneirophanta lucerna sp. nov. These species were distinguished from each other and from congeners by the arrangement, and number of ventrolateral tube feet and ossicle types. We also reported Oneirophanta mutabilis mutabilis Théel, 1879 for the first time from the Mariana fore-arc area, and we recorded Deima validum validum for the second time from the South China Sea. The taxonomy of these new species and new records is discussed, and a phylogenetic analysis based on a concatenated dataset of 16S and COI genes was conducted. Additionally, the inter- and intraspecific genetic divergences we calculated among deimatid species. The results support the assignment of these new species to the genus Oneirophanta and their separation from congeners. A description of the main morphological characters of Oneirophanta species is also provided. The data were collected from geographically diverse areas and suggest that species of Deimatidae were abundant in the Pacific Ocean and occupied a wide range of depths.

Key words: COI, deep-sea, morphology, Oneirophanta, phylogeny, sea cucumber, SEM, taxonomy

Oneirophanta lucerna sp. nov. (Holotype IDSSE-2023-0208-HS02)
A, B in situ images C dorsal view D ventral view.

 Scale bars: 5 cm.

Yunlu Xiao and Haibin Zhang. 2024. Three New Species and One New Record of Deimatidae (Echinodermata, Holothuroidea, Synallactida) discovered in the South China Sea and the Mariana fore-arc area using integrative taxonomic methods. ZooKeys. 1195: 309-335. DOI: 10.3897/zookeys.1195.115913

[Paleontology • 2024] Ophiactis hex • Fossil Evidence for the ancient link between clonal fragmentation, Six-fold Symmetry and an epizoic lifestyle in asterozoan echinoderms (Echinodermata: Asterozoa: Ophiuroidea)

  Ophiactis hex 

Thuy, Numberger-Thuy, Härer, Kroh, Winkler & Schweigert, 2024

DOI: 10.1098/rspb.2023.2832

 

Abstract

Asexual reproduction by means of splitting, also called fissiparity, is a common feature in some asterozoan groups, especially in ophiactid brittle stars. Most fissiparous brittle stars show six instead of the usual five rays, live as epibionts on host organisms, and use clonal fragmentation to rapidly colonize secluded habitats and effectively expand the margins of their distribution area. While the biology and ecology of clonal fragmentation are comparatively well understood, virtually nothing is known about the evolution and geological history of that phenomenon. Here, we describe an exceptional fossil of an articulated six-armed brittle star from the Late Jurassic of Germany, showing one body half in the process of regeneration, and assign it to the new species Ophiactis hex sp. nov. Phylogenetic inference shows that the fossil represents the oldest member of the extant family Ophiactidae. Because the Ophiactis hex specimen shows an original six-fold symmetry combined with a morphology typically found in epizoic ophiuroids, in line with recent fissiparous ophiactid relatives, we assume that the regenerating body half is an indication for fissiparity. Ophiactis hex thus shows that fissiparity was established as a means of asexual reproduction in asterozoan echinoderms by the Late Jurassic.

Keywords: Ophiuroidea, late Jurassic, fissiparous, phylogeny, Ophiactidae

  Ophiactis hex sp. nov., holotype SMNS 70508; from the Nusplingen Lithographic Limestone (Nusplingen Formation), Beckeri Zone, Ulmense Subzone, late Kimmeridgian, Late Jurassic, Nusplingen, Germany.
 Light photographs of the complete specimen exposing the dorsal side 

Systematic palaeontology

Class Ophiuroidea Gray, 1840

Superorder Ophintegrida O'Hara et al., 2017

Order Amphilepidida O'Hara et al., 2017

Superfamily Ophiactoidea Ljungman, 1867

Family Ophiactidae Matsumoto, 1915

Genus Ophiactis Lütken, 1856

Ophiactis hex sp. nov.

 Species diagnosis: Small ophiactid with six arms, dorsal side of disc with a dense cover of granules and spinelets; lateral arm plates with outer surface covered by small tubercles arranged in a faint vertical striation; arm spines large and slightly flattened; distalmost arm segments with at least one hook-shaped arm spine.

  Etymology: Species name (used as noun in apposition) referring to Hex, the organic/inorganic/magical super-computer of Terry Pratchett's Unseen University, capable of thinking the unthinkable.

 

Ben Thuy, Lea D. Numberger-Thuy, Jürgen Härer, Andreas Kroh, Viola Winkler and Günter Schweigert. 2024. Fossil Evidence for the ancient link between clonal fragmentation, Six-fold Symmetry and an epizoic lifestyle in asterozoan echinoderms. Proc. R. Soc. B. 291: 20232832. DOI: 10.1098/rspb.2023.2832

[Invertebrate • 2024] Benthogenia mahi • Revision of the Genus Benthogenia Fisher, 1911 (Echinodermata: Asteroidea: Porcellanasteridae), with Description of A New Species and ossicle anatomy

 Benthogenia mahi 

Fau, 2024

 

sciencepress.mnhn.fr/en/periodiques/zoosystema 

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Porcellanasteridae Sladen, 1883 is a family of mud-dwelling sea stars, living in bathyal and abyssal environments. Among the twelve currently recognized genera of this family, Benthogenia Fisher, 1911 is the only one known occurring at depth shallower than 1000 m. Benthogenia differs from all other porcellanasterids by having cribriform organs between all its marginals, from the disc to the tip of the arms. Benthogenia cribellosa Fisher, 1911 is reported from a locality as shallow as 111 m, and a new species, Benthogenia mahi n. sp., is described from material housed in the Muséum national d’Histoire naturelle, Paris (MNHN). Benthogenia mahi n. sp. is represented by twelve specimens, collected at depth ranging from 400 to 1200 m during four different expeditions. Benthogenia cribellosa is represented by two specimens from the MNHN, plus the holotype and two specimens from the National Museum of Natural History (Smithsonian Institution), Washington D.C. Benthogenia mahi n. sp. differs from B. cribellosa mostly by having more robust arms, fewer oral and adambulacral spines, and by the cribriform organs not covering the entire surface of the superomarginals of the disc. Molecular data (16S rDNA) were also used as an independent dataset to test for divergence between the two species. Benthogenia mahi n. sp. occurs in New Caledonia, Solomon Islands and Vanuatu, whereas B. cribellosa is only known from the Philippines. Detailed descriptions of both species are provided, as well as a detailed description of the skeleton of the new species.

KEYWORDS: Porcellanasteridae, deep-sea fauna, systematics, anatomy, new species

 Benthogenia mahi n. sp. in abactinal (C, E) and actinal view (D, F):
C, D, MNHN-IE-2007-1580; E, F, MNHN-IE-2019-3879.

Scale bars: 5 cm.

 Benthogenia mahi n. sp.

Marine FAU. 2024. Revision of the Genus Benthogenia Fisher, 1911 (Asteroidea, Echinodermata), with Description of A New Species and ossicle anatomy. ZOOSYSTEMA. 46(11); 269-284.  DOI: 10.5252/zoosystema2024v46a11

  sciencepress.mnhn.fr/en/periodiques/zoosystema/46/11

  twitter.com/echinoblog/status/1790757053151183020

[Invertebrate • 2019] Ophiopsila xmasilluminans • Brittle Stars from A Submarine Cave of Christmas Island, northwestern Australia, with Description of A New Bioluminescent Species (Echinodermata: Ophiuroidea) and Notes on Its Behaviour

Ophiopsila xmasilluminans

Okanishi, Oba & Fujita, 2019

RAFFLES BULLETIN OF ZOOLOGY. 67: 

 Abstract

 Three species of ophiuroids are reported from a shallow water submarine cave on Christmas Island in northwestern Australia, including a new bioluminescent species, Ophiopsila xmasilluminans, which is described herein on the basis of 15 specimens. This new species occurs on sandy bottoms in the cave with disc buried and arms extended above the substratum. This species possesses a disc entirely covered by thick skin with small and delicate embedded scales and granules; 3 oral papillae, basically flat, fan-shaped but sometimes innermost or middle papilla spiniform; diamond shaped oral shield with rounded edges, as long as wide; long and flat arm spine; inner tentacle scale narrow, flat and long, arms approximately 18 times the disc diameter. We describe bioluminescence and burying behaviour, which suggest adaptation to submarine cave environments. Also reported herein is a rarely encountered species, Ophiomora elegans, based on a single specimen. Ophiomora elegans was previously known only from southern Mozambique, the east coast of Africa and the Ryukyu Islands. We also include a new record of Ophioconis claviculata, which was previously known only from the Ryukyu Islands. 

Key words: brittle star, endemism, new species, submarine cave, bioluminescence, Christmas Island

 Ophiopsila xmasilluminans new species, living, anesthetised
(A: one paratype, RUMF-ZE-00152), in situ (B, C: specimens not collected):
A, aboral view; B, with buried disc and extended arms; C, an excavated specimen.

  

Ophiopsila xmasilluminans new species

Diagnosis. Disc surface entirely covered by thick skin with embedded small and delicate scales and granules; 3 oral papillae, basically as scales, but sometimes spiniform for one on innermost or middle position; diamond-shaped oral shield with rounded edges, as long as wide; long and flat arm spines, 6 in maximum number; inner tentacle scale narrow, flat and long; arms approximately 18 times longer than disc diameter.

Etymology. The specific name is an adjective in apposition formed as a compound of the island name “xmas” and the Latin participle, illuminans, meaning “lighting”, referring to its sampling locality name (Christmas Island) and luminescence. 

Common Japanese name. Dohkutsu-hikari-kumohitode. 

Distribution. Known only from the type locality, a submarine cave called as “Thunderdome Cave”, northern coast of Christmas Island, northwestern Australia, approximately 10 m depth (type locality, Fig. 1). Tan et al (2014) noted that Ophiopsila pantherina [= this new species] was also found at “Thundercliff Cave”, which is located near Thunderdome Cave. However, specimens of this species were only collected from Thunderdome Cave by the last author (Yoshihisa Fujita). 

Habitat. All type specimens of Ophiopsila xmasilluminans new species were collected in sandy bottoms in the submarine cave, with buried disc and arms extended into the water (Fig. 2B).

 Masanori Okanishi, Yuichi Oba and Yoshihisa Fujita. 2019. Brittle Stars from A Submarine Cave of Christmas Island, northwestern Australia, with Description of A New Bioluminescent Species Ophiopsila xmasilluminans (Echinodermata: Ophiuroidea) and Notes on Its Behaviour. RAFFLES BULLETIN OF ZOOLOGY. 67: 421–439. DOI 10.26107/RBZ-2019-0034

南の島のクリスマスイルミネーション？クリスマス島（豪）の海底洞窟から新種の光るクモヒトデを発見！ （大場裕一教授ら） 中部大学の研究活動 中部大学 www3.chubu.ac.jp/research/news/25228/

      

[Invertebrate • 2024] Rhianastra isosceles & Bathyceramaster kelliottae • Two New Taxa of Goniasteridae (Echinodermata: Asteroidea) and Noteworthy Observations of Deep-Sea Asteroidea by the NOAA Ship Okeanos Explorer in the North and Tropical Atlantic

Bathyceramaster kelliottae n. sp.  

Rhianastra isosceles n. gen., n. sp.

Mah, 2024

DOI: 10.11646/zootaxa.5432.4.2

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Abstract

Two new species and one new genus, collected by NOAA ship Okeanos Explorer, Bathyceramaster kelliottae n. sp. and Rhianastra isosceles n. gen., n. sp. (Goniasteridae; Asteroidea) are described from deep-sea settings in the North Atlantic. Two potentially undescribed species are observed from imagery and new in situ observations further elucidate life modes and feeding behavior of several species from North Atlantic deep-sea habitats. New occurrences of Atlantic Neomorphaster are presented and Neomorphaster forcipatus is synonymized with Neomorphaster margaritaceus.

Echinodermata, NOAA ship Okeanos Explorer, deep-sea, feeding observations, new species, taxonomy, Stichasteridae, Zoroasteridae

Rhianastra isosceles n. gen., n. sp.

Bathyceramaster kelliottae n. sp. 

Christopher L. Mah. 2024. Two New Taxa of Goniasteridae (Asteroidea, Echinodermata) and Noteworthy Observations of Deep-Sea Asteroidea by the NOAA Ship Okeanos Explorer in the North and Tropical Atlantic.  Zootaxa. 5432(4); 461-508. DOI: doi.org/10.11646/zootaxa.5432.4.2

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Two newly described sea stars named in honor of ocean explorers, including NOAA’s Kelley Suhre

https://oceanexplorer.noaa.gov/news/oer-updates/2024/mah-star-24.html

[Invertebrate • 2023] Xyloplax princealberti (Echinodermata: Asteroidea) • A New Species that is not always associated with Wood Falls

Xyloplax princealberti 

Payne, Tilic, Boschen-Rose, Gannon, Stiller, Hiley, Grupe, Mah & Rouse, 2023

DOI: 10.3390/d15121212 

 twitter.com/_Cheyenne_Payne 

Abstract

Xyloplax is a genus of three species of sea stars previously found only on sunken wood in the deep ocean. Their circular and petaloid bodies, which lend them their common name “sea daisy”, and their presumed exclusive diet of wood make them an unusual and rare element of deep-sea ecosystems. We describe here the fourth species of Xyloplax from the eastern Pacific Ocean, Xyloplax princealberti n. sp., which ranges from offshore Canada to the Gulf of California (Mexico) and Costa Rica. Though sampled geographically close to another described species of Xyloplax from the northeastern Pacific, X. janetae, this new species is unique morphologically and according to available DNA data. The short abactinal spines are the most obvious feature that distinguishes X. princealberti n. sp. from other Xyloplax. The minimum distance for mitochondrial cytochrome c oxidase subunit I from Xyloplax princealberti n. sp. to the only other available Xyloplax, X. janetae, was 13.5%. We also describe Ridgeia vestimentiferan tubeworm bushes from active hydrothermal vents as a new Xyloplax habitat, the first record of a non-wood substrate, and a new reproductive strategy, simultaneous hermaphroditism, for this genus. We generated the first mitochondrial genome for a member of Xyloplax and analyzed it with other available asteroid data using nucleotide-coding or amino acid (for protein-coding genes) plus nucleotide coding (for rRNA genes). The nucleotide-coding results place Xylopax as part of the clade Velatida, consistent with a previous phylogenomic analysis that included Xyloplax princealberti n. sp. (as Xyloplax sp.), though the placement of Velatida within Asteroidea differed. The amino acid plus nucleotide coding recovered Velatida to be a grade with X. princealberti n. sp. as sister group to all other Asteroidea.

Keywords: deep sea; asteroid; hydrothermal vent

 Collection sites and representative individuals of Xyloplax princealberti n. sp.
 (A) Recovered wood block from Juan de Fuca Ridge, offshore Canada, showing a specimen on the surface (indicated with white arrow). Inset shows an animal in situ on the wood surface. (B) Ridgeia vestimentiferan bush sampled at the Juan de Fuca Ridge, offshore Canada. (C) Wood found with seven specimens of Xyloplax princealberti n. sp. at 2421 m on the Alarcón Rise, Gulf of California, Mexico. (D) Wood deployment at 1845 m at Jaco Scar, offshore Costa Rica. (E) Specimens in abactinal view collected from wood deployment in the Juan de Fuca Ridge, offshore Canada. (F) Specimens in abactinal view collected from wood in the Gulf of California, Mexico. (G) Two specimens in abactinal view from Jaco Scar, offshore Costa Rica. (H) Two specimens in actinal view from Jaco Scar, offshore Costa Rica.

 Images of Xyloplax princealberti n. sp. from the wood deployment in Juan de Fuca Ridge, offshore Canada.
(A) Live specimen (from lot SIO-BIC E6809), abactinal view. * indicates hydropore. (B) Live specimen (lot SIO-BIC E6809), actinal view. (C) Closeup of the abactinal view of a live specimen (lot SIO-BIC E6809), showing adambulacral spines and short abactinal spinelets. * indicates hydropore. (D) Closeup of the actinal view of a live specimen (lot SIO-BIC E6809), showing tube feet and adambulacral spines. (E) Preserved holotype (SIO-BIC E11463), abactinal view. (F) Preserved holotype (SIO-BIC E11463), actinal view. (G) Preserved holotype (SIO-BIC E11463), closeup ambulacral area showing 7 tube feet and abactinal spinelets, abactinal view.

VELATIDA

XYLOPLACIDAE Baker, Rowe & Clark, 1986 

Xyloplax Baker, Rowe & Clark, 1986 

 

Xyloplax princealberti n. sp.

Diagnosis: Xyloplax with rounded abactinal spine bases, spines uniformly short. Two to three adambulacral spines per plate; more than 100 total spines around margin. Tube feet rounded, bulbous, up to ten per segment. Terminal plates badge-shaped. Mouth, gut, and anus absent. “Viviparous”, simultaneous hermaphrodite.

Etymology: This species honors His Serene Highness Prince Albert II of Monaco for his efforts to protect the marine environment through the Prince Albert II of Monaco Foundation.

  Cheyenne Y. Payne, Ekin Tilic, Rachel E. Boschen-Rose, Amanda Gannon, Josefin Stiller, Avery S. Hiley, Benjamin M. Grupe, Christopher L. Mah and Greg W. Rouse. 2023. Xyloplax princealberti (Asteroidea, Echinodermata): A New Species that is not always associated with Wood Falls. Diversity. 15(12), 1212. DOI: 10.3390/d15121212

(This article belongs to the Special Issue Diversity and Biogeography of Sea Stars (Echinodermata, Asteroidea))

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