Benthodytes jiaolongi: A new species of deep-sea Sea Cucumber from the Western Pacific.

Sea Cucumbers (Holothuroidea) are a class of Echinoderms that have become elongated and worm-like, effectively becoming secondarily bilaterally symmetrical. Like all Echinoderms they have a calcareous exoskeleton, but this is greatly reduced, typically only occurring as ossicles within the epidermis. The muscle structure of Sea Cucumbers is instead supported by a layer of modified collagen that can be stiffened or relaxed at will, allowing for a more flexible body than that of other Echinoderms. The Family Psychropotidae currently comprises 37 species of deep-sea Sea Cucumbers, which are elongated and flattened to facilitate swiming, and typically have a large tail-appendage of uncertain purpose. Although the Psychropotidae were first discovered during the H.M.S. Challenger Expedition of 1872–1876, the group are relatively understudied, and phylogenetic relationships within the family poorly understood.

In a paper published in the journal ZooKeys on 9 March 2022, Chuan Yu of the School of Oceanography at Shanghai Jiao Tong University, and the Key Laboratory of Marine Ecosystem Dynamics at the Second Institute of Oceanography of the Ministry of Natural Resources, Dongsheng Zhang, also of the School of Oceanography at Shanghai Jiao Tong University, and the Key Laboratory of Marine Ecosystem Dynamics at the Second Institute of Oceanography of the Ministry of Natural Resources, and of the Southern Marine Science and Engineering Guangdong Laboratory, Ruiyan Zhang, again of the School of Oceanography at Shanghai Jiao Tong University, and Chunsheng Wang, once again of the School of Oceanography at Shanghai Jiao Tong University, and the Key Laboratory of Marine Ecosystem Dynamics at the Second Institute of Oceanography of the Ministry of Natural Resources, the Southern Marine Science and Engineering Guangdong Laboratory, and of the State Key Laboratory of Satellite Ocean Environment Dynamics of the Ministry of Natural Resources, describe a new species of Psychropotid Sea Cucumber from the Western Pacific.

The new species is described from four specimens collected from the Weijia Guyot and Kyushu-Palau Ridge by the Jiaolong Human Operated Vehicle. The new species is placed in the genus Benthodytes , and given the specific name jiaolongi, in reference to the vehicle used to recover the specimens.

 

Benthodytes jiaolongi specimen (RSIO6017101, paratype) in situ on the Kyushu-Palau Ridge. Yu et al. (2022).

Benthodytes jiaolongi is a red-to-violet elongated and subcylindrical Sea Cucumber reaching about 25 cm in length. It has eighteen tentacles surrounding its mouth, and two rows of midventral tube feet. 

Benthodytes jiaolongi. (A) Dorsal view, (B) ventral view. Yu et al. (2022).

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Psolidium lonchostinum & Psolidium nanoplax: Two new species of Sea Cucumbers from the Brazilian Coast.

Sea Cucumbers (Holothuroidea) are a class of Echinoderms that have become elongated and worm-like, effectively becoming secondarily bilaterally symmetrical. Like all Echinoderms they have a calcareous exoskeleton, but this is greatly reduced, typically only occurring as ossicles within the epidermis. The muscle structure of Sea Cucumbers is instead supported by a layer of modified collegen that can be stiffened or relaxed at will, allowing for a more flexible body than that of other Echinoderms. The Holothuroidea fauna from the Brazilian coast is still poorly know, but efforts over the last 18 years have improved our knowledge of the Hlothuroid biodiversity.

In a paper published in the journal Zoological Studies on 4 February 2020, Luciana Martins and Marcos Tavares of the Museu de Zoologia at the Universidade de São Paulo, describe two new species of the Holothuroid genus Psolidium from São Paulo and Rio Grande do Sul. This is the first record of the genus from the Brazilian coast.

The first new species is named Psolidium lonchostinum, where 'lonchostinum' is formed by the combination of two Greek words, lonche (spear) and ostinos (bony, Latinized to ostinum), and refers to the thorn-shaped ossicles (branched rods) found in the sole. The species is described from sixteen specimens collected with the aid of a Van Veen grab and a rectangular dredge from infaunal assemblages off the coast of São Paulo.

(A)–(F) Psolidium lonchostinum. (A)–(D) Holotype (MZUSP 744). (A) upper view; (B) detail of dorsal tube feet (black arrow); (C) detail of lateral scales (white arrow); (D) ventral view; detail of ambulacral feet (note the inner and outer rows of tube feet: black and white circles, respectively); (E) paratype (MZUSP 591) detail of ventral tube feet (black arrow); (F) outline of the calcareous ring. Abbreviations: R, radial plate; IR, interradial plate. Note in (F) interradial plate entire and radial plate notched. Scale bars: (A) 4 mm; (D) 2 mm; (E) 3 mm; (F) 500 μm. Martins & Tavares (2020).

The body of Psolidium lonchostinum is flat, oval in outline, 6–8.3 mm long and 4–5.9 mm wide. The mouth and anus covered by a variable number of small and irregular scales (0.8–1 mm wide), up to two tube feet penetrate each scale dorsally and laterally. The species lacks oral and anal valves.

The marginal dorsolateral scales are 0.1–0.3 mm, smaller than the dorsal scales.The species has a thin sole, lacking scales, tube feet arranged in a double series: inner series of large tube feet and outer peripheral series of smaller tube feet close to the ventral margin, which lacks mid-ventral (sole) radial series of tube feet, except for a cluster (up to 5) posteriorly and anteriorly. The calcareous ring is simple, lacking posterior processes; radial and interradial plates united only at the base, notched only at the radial plate.

Dorsal/lateral ossicles are smooth and perforated plates, irregular in outline, with undulating margins (100–120 μm long) and round holes (5–20 μm in diameter) and branched rods (thorn ossicles) (40–60 μm long). Dorsal tube feet with perforated rods (70–130 μm long), with undulating in margins.

(A)–(F) Psolidium lonchostinum, holotype (MZUSP 744). Scanning electron microscope photomicrographs of the ossicles. (A) scale from dorsal body wall, showing canals for tube feet (white arrow); (B) smooth plate from dorsal body; (C) branched rods (thorn ossicle) (black arrow); (D) rod from dorsal tube feet; (E)–(F) knobbed plates from sole. Scale bars: (A)–(B) 50 μm; (C) 40 μm; (D)–(F) 50 μm. Martins & Tavares (2020).

The sole of Psolidium lonchostinum is covered with single-layered and elongated plates (130–150 μm long), perforated at their entire length and knobbed at center and margins, and smooth plates slightly knobbed in the margin (70–100 μm long). Ventral tube feet with perforated rods with irregular, curved and undulating margins (80–160 μm long) and an end-plate.

(A)–(F) Psolidium lonchostinum, holotype (MZUSP 744). Scanning electron microscope photomicrographs of the ossicles. (A) four-holed smooth plate from sole, ventral view; (B) four-holed smooth plate from sole, dorsal view; (C)–(D) multiperforated smooth plate from sole, dorsal view; (E) four-holed smooth plate from sole, lateral view; (F) rod from ventral tube feet, dorsal view. Scale bars: (A)–(B) 30 μm; (C) 40 μm; (D)–(E) 50 μm; (F) 80 μm. Martins & Tavares (2020).

The second species is named Psolidium nanoplax, where 'nanoplax' is formed by the Greek words, nano (little) and plax (plate), in reference to the reduced length of the sole plates. The species is described from two specimens collected from the offshore part of the Campos Basin of southeastern Brazil, with the aid of an ELOS dredge.

(A)–(F) Psolidium nanoplax (MZUSP 589, 592). (A) Lateral view of holotype preserved in ethanol (note anal cone in white arrow); (B) upper view of paratype-MZUSP 592 preserved in ethanol (note mouth and anus in black and red arrows, respectively); (C) detail of anal cone holotype-MZUSP 592 (note anal cone and papillae, in white and red arrows, respectively); (D) detail of dorsal tube feet holotype-MZUSP 592 (red arrow); (E) detail of lateral scales paratype-MZUSP 592; (F) ventral view detail of ambulacral feet paratype-MZUSP 592, (note the inner and outer rows of tube feet: black and white arrows, respectively); (G) calcareous ring (H) detail of retractor muscle (white arrow) and (I) outline of the calcareous ring paratype-MZUSP 592. Abbreviations: R, radial plate; IR, interradial plate. Note, only radial plate notched. Scale bars: (A) 5 mm; (B) 4 mm; (C) 500 μm, (D) 500 μm, (E) 0.5 mm; (F) 2 mm; (G)–(I) 500 μm. Martins & Tavares (2020).

The body of the first of the specimens was elongate, reaching 11 mm, the smaller was ventrally and dorsally flattened and measured 8 mm. Ths mouth and anus lack valves, the anal cone is slightly raised. The dorsal and lateral body are covered with conspicuous imbricating scales (0.8–1 mm) and without granules or tubercles at the surface. One inconspicuous tube foot is present at each scale. The marginal dorsolateral scales smaller than dorsal scales (0.1–0.3 mm). Ventral sole lacking scales, tube feet arranged in a double series: inner series of large tube feet and outer peripheral series of smaller tube feet close to ventral margin, mid-ventral tube feet absent. Calcareous ring simple, lacking posterior processes, radial and interradial plates united only at the base; radial plate notched.

The dorso-lateral ossicles are knobbed and multiperforated single plates, flat, oval in outline, heavily knobbed on one side, smooth on the other surface, knobbed edges (150–170 μm long) and rounded holes 10–20 μm in diameter.

(A)–(I) Psolidium nanoplax (MZUSP 589). Scanning electron microscope photomicrographs of the ossicles. (A) knobbed plate from dorsal body (B) supporting rod from dorsal tube feet; (C) 'cup-like' plates from sole in dorsal view; (D) 'cup-like' multiperforated plates from sole in ventral view; (E) 'cup-like' four-holed plates from sole in dorsal view; (F) 'cup-like' plates from sole in lateral view (G) knobbed plates from sole and (H)–(I) knobbed plates from ventral tube feet. Scale bars: (A)–(B) 50 μm; (C) 20 μm; (D)–(I) 30 μm. Martins & Travares (2020).

The sole is covered with with knobbed and multiperforated single plates, strongly concave, oval in outline, heavily knobbed on one side, smooth on the other surface, knobbed edges (70–100 μm long), and round holes 15–20 μm in diameter and 'cup-like' multiperforated plates, concave, oval in outline (50–70 μm long) 10–15 μm in diameter. 

Dorsal tube feet with supporting rods, curved with one central perforation and one central apophysis (80–150 μm). Ventral tube feet with knobbed and multiperforated plates.

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Epitomapta simentalae: A new species of Sea Cucumber from Acapulco Bay, Mexico.

Sea Cucumbers (Holothuroidea) are a class of Echinoderms that have become elongated and worm-like, effectively becoming secondarily bilaterally symmetrical. Like all Echinoderms they have a calcareous exoskeleton, but this is greatly reduced, typically only occurring as ossicles within the epidermis. The muscle structure of Sea Cucumbers is instead supported by a layer of modified collegen that can be stiffened or relaxed at will, allowing for a more flexible body than that of other Echinoderms. 

In a paper published in the journal ZooKeys on 15 January 2018, Francisco Alonso Solís-Marín of the Colección Nacional de Equinodermos 'Dra. Ma. Elena Caso Muñoz' at the Universidad Nacional Autónoma de México, Carlos Andrés Conejeros-Vargas of Posgrado en Ciencias del Mar y Limnología at the Universidad Nacional Autónoma de México, Andrea Alejandra Caballero-Ochoa of the Facultad de Ciencias at the Universidad Nacional Autónoma de México, and Julio Adrian Arriaga-Ochoa, also of Posgrado en Ciencias del Mar y Limnología at the Universidad Nacional Autónoma de México, describe a new species of Sea Cucumber from Acapulco Bay on the Pacific Coast of Guerrero State, Mexico.

The new species is placed in the genus Epitomapta, which currently contains two species of small, worm-like Sea Cucumbers from the Atlantic Coast of the United States and the Pacific Coast of Mexico, and given the specific name simentalae, in honour of Delia Rosalba Simental Crespo, for her contributions to the study and conservation of Echinoderms on the coasts of Mexico. The species is described from 127 specimens collected from well aerated sandy sediments at depths of between four and ten meters. These specimens are pink to light purple in colour and less than 2 cm long, with smooth skin and twelve tentacles, each with two or three pairs of digits and a terminal digit, plus up to six sensory cups.

Epitomapta simentalae. Lateral view of preserved specimen. Solís-Marín et al. (2019).

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Borniopsis mortoni: A new species of Galeommatoid Bivalve from Shikoku Island, Japan.

Galeommatoid Bivalves are an extremely diverse group of bivalves from shallow and intertidal waters around the world. They are noted for the commensual relationships that many species form with other invertebrates, living either on the bodies of their partners or within their burrows. Members of the genus Borniopsis are known from around the coast of eastern Asia, where they have been found living on the bodies of Mantis Shrimps, Crabs, Holothurians (Sea Cucumbers), Sipunculid Worms, Echiurans (Spoon Worms) and probably Tanaid Crustaceans.

In a paper published in the journal ZooKeys on 7 September 2016 Ryutaro Goto of the Museum of Zoology and Department of Ecology and Evolutionary Biology at the University of Michigan and Hiroshi Ishikawa of Uwajima on Shikoku Island, Japan, describe a new species of Borniopsis from Sea Cucmbers found on mud flats at the mouth of the Souzu River on southwestern Shikoku Island.

The new species is named Borniopsis mortoni, in honour of Brian Morton of the Univeristy of Hong Kong for his contributions to marine biology, marine ecology and malacology, including the discovery of many Galeommatoid species. Borniopsis mortoni was found living on the bodies of the Sea Cucumber Patinapta ooplax, a Worm-like burrowing species, with about 70% of the Sea Cucumbers inspected hosting the bivalves and some having more than ten attached.

Patinapta ooplax with multiple individuals of Boriopsis mortoni attached. Goto & Ishikawa (2016).

The Bivalves are small, with the largest specimens reaching 4.1 mm by 2.8 mm, and have thin, elongate and slightly inflated shells. The periostracum (covering of the shell) is tan to brown, withblack markings. They attach to their hosts using both their foot and byssal threads (thick silky threads produced by some Bivalves as a way of attaching themselves to substrates).

A crawling individual of Boriopsis mortoni. Goto & Ishikawa (2016).

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Symbiosis and the success of Galeommatoid Bivalves.                                                       Galeommatoid Bivalves are small (under 20 mm, mostly under 10 mm) nondescript Clams found in both soft and hard bottomed marine environments (which is unusual, as most Bivalves...

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A new species of Sea Cucumber from the Kermadec Islands.

Sea Cucumbers (Holothuroidea) are a class of Echinoderms that have become elongated and worm-like, effectively becoming secondarily bilaterally symmetrical. Like all Echinoderms they have a calcareous exoskeleton, but this is greatly reduced, typically only occurring as ossicles within the epidermis. The muscle structure of Sea Cucumbers is instead supported by a layer of modified collegen that can be stiffened or relaxed at will, allowing for a more flexible body than that of other Echinoderms. 

In a paper published in the journal Zootaxa on 12 October 2012, Mark O'Loughlin of the Marine Biology Section at Museum Victoria and Didier Van den Spiegel of the Section invertebrés non-insects at the Musée royal de l’Afrique centrale in Tervuren, Belgium, describe a new species of Sea Cucumber from the Kermadec Islands; a New Zealand territory in the South Pacific, roughly half way between North Island and Tonga, discovered during the Kermadec Biodiscovery Expedition by RV Braveheart, which visited the islands from 9 to 29 of May 2011.

The new Cucumber is placed in the genus Chiridota and given the specific name kermadeca, meaning from the Kermadecs. It is a brown Sea Cucumber up to 20 mm in length and 5 mm in width, found on Stawell Shoal and at Boat Cove in the Kermadec Islands at depths of 10-24 m. It has 10 tentacles surrounding its mouth, rather than the 12 seen in other members of the genus Chiridota.

Chiridota kermadeca. O'Loughlin & Van den Spiegel (2012).

Dermal ossicles from Chiridota kermadeca. O'Loughlin & Van den Spiegel (2012).

See also Are the Vetulicolians Deuterostomes? A new species of Crinoid from the Southern Ocean, Pumice raft linked to Havre Seamount, not Monowai, Pumice raft suggests eruption from Mount Monowai and Marine Invertebrates on Sciency Thoughts YouTube.

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