Flourishing chemosynthetic life at the greatest depths of hadal trenches

Hadal trenches, some of the Earth’s least explored and understood environments, have long been proposed to harbour chemosynthesis-based communities1,2. Despite increasing attention, actual documentation of such communities has been exceptionally rare3,4. Here we report the discovery of the deepest and the most extensive chemosynthesis-based communities known to exist on Earth during an expedition to the Kuril–Kamchatka Trench and the western Aleutian Trench using the manned submersible Fendouzhe. The communities dominated by siboglinid Polychaeta and Bivalvia span a distance of 2,500 km at depths from 5,800 m to 9,533 m. These communities are sustained by hydrogen sulfide-rich and methane-rich fluids that are transported along faults traversing deep sediment layers in trenches, where methane is produced microbially from deposited organic matter, as indicated by isotopic analysis. Given geological similarities with other hadal trenches, such chemosynthesis-based communities might be more widespread than previously anticipated. These findings challenge current models of life at extreme limits and carbon cycling in the deep ocean.</p

Notes for genera: basal clades of Fungi (including Aphelidiomycota, Basidiobolomycota, Blastocladiomycota, Calcarisporiellomycota, Caulochytriomycota, Chytridiomycota, Entomophthoromycota, Glomeromycota, Kickxellomycota, Monoblepharomycota, Mortierellomycota, Mucoromycota, Neocallimastigomycota, Olpidiomycota, Rozellomycota and Zoopagomycota)

Compared to the higher fungi (Dikarya), taxonomic and evolutionary studies on the basal clades of fungi are fewer in number. Thus, the generic boundaries and higher ranks in the basal clades of fungi are poorly known. Recent DNA based taxonomic studies have provided reliable and accurate information. It is therefore necessary to compile all available information since basal clades genera lack updated checklists or outlines. Recently, Tedersoo et al. (MycoKeys 13:1--20, 2016) accepted Aphelidiomycota and Rozellomycota in Fungal clade. Thus, we regard both these phyla as members in Kingdom Fungi. We accept 16 phyla in basal clades viz. Aphelidiomycota, Basidiobolomycota, Blastocladiomycota, Calcarisporiellomycota, Caulochytriomycota, Chytridiomycota, Entomophthoromycota, Glomeromycota, Kickxellomycota, Monoblepharomycota, Mortierellomycota, Mucoromycota, Neocallimastigomycota, Olpidiomycota, Rozellomycota and Zoopagomycota. Thus, 611 genera in 153 families, 43 orders and 18 classes are provided with details of classification, synonyms, life modes, distribution, recent literature and genomic data. Moreover, Catenariaceae Couch is proposed to be conserved, Cladochytriales Mozl.-Standr. is emended and the family Nephridiophagaceae is introduced

Microscopic Anatomy of the Tentacles of Thysanocardia nigra Ikeda, 1904 (Sipuncula) from the Sea of Japan

Fine morphology of the tentacular apparatus of the sipunculan Thysanocardia nigra Ikeda, 1904 was conducted as a part of a larger study of microscopic anatomy in the species. The tentacular apparatus is composed of two rings of tentacles, the dorsal and oral crowns. The dorsal, or nuchal, crown consists of an arc of nuchal tentacles dorsally enclosing the heart -shaped nuchal organ. The oral disk carries numerous peripheral tentacles arranged in oral crown surrounding the mouth. Peripheral tentacles are arranged in paired rows, additional tentacles being developed posteriorly so as to form a radial series of U -shaped festoons. The parallel festoons extend down the oral disk and run alongside the spherical head. New pairs of festoons appear at the base of the nuchal crown. The tentacles are heart-shaped in cross section, the oral surface being widest. The nuchal tentacles face the oral disk by the oral surface while the peripheral, or oral, tentacles are twisted at the base at nearly right angles, so to face a ciliary groove of the corresponding festoon. The central groove of festoon is composed of a median ridge bordered by longitudinal lateral ridges with long cilia. The oral surface of tentacles is constructed of a multiciliated, pseudostratified, columnal epithelium with some intraepidermal mucous cells. There are three longitudinal tentacular canals lined by peritoneum. Hemerythrocytes flow through the lumen of the canals. Tentacles and grooves of festoons form a filtering system upon which food particles can be trapped. The filtering apparatus of Thysanocardia shows remarkable similarities with a filtering system of sabellid polychaetes

Taxonomic Study of the Kinorhyncha in Japan -I. Pycnophyes tubuliferus Adrianov, 1989 (Kinorhyncha : Homalorhagida) from Japan

A pycnophyid kinorhynch, Pycnophyes tubuliferus Adrianov, 1989, collected from muddy sediment at Tanabe Bay, Honshu Island, Japan is re-described and illustrated. This is the first record of the order Homalorhagida and the genus Pycnophyes from Japanese waters, and the fourth genus of the class Kinorhyncha from Japan. Previously P. tubuliferus was found only in a few localities alongside the Russian and Korean coasts in the western part of the Sea of Japan, and this is the first finding of this species outside the Sea of Japan. Detailed morphology of the species has been studied using Nomarsky microscopy and SEM for the first time. Basic taxonomic characters were compared from zoogeographic points of view among specimens representing populations from the Sea of Japan (including typematerial) and the Pacific coast of the mainland of Japan. The new diagnosis of the species has been proposed

Taxonomic Study of the Kinorhyncha in Japan. III. Echinoderes sensibilis n. sp. (Kinorhyncha: Cyclorhagida) from Tanabe Bay

A new species of echinoderid kinorhynch, Echinoderes sensibilis, is described and illustrated using light and electron microscopy. The specimens were collected from masses of the red algae Corallina pilulifera growing in intertidal pools in Tanabe Bay, Honshu Island, Japan. Diagnostic characters of E. sensibilis include the presence of middorsal spines on segments 6-10; lateral spines/tubules on segments 4, 7-12; remarkable trapezium-like subventral fields of minute cuticular hairs on segments 5-12. The positions of numerous sensory spots, large sieve areas, glandular tubes and the shape of terminal tergal and sternal extensions are also diagnostic. All taxonomic characters used for this description are illustrated by SEM. Echinoderes sensibilis constitutes the fifty-eighths valid species of the genus Echinoderes and the fourteenth species described from the Pacific Ocean. This is the third representative of Pacific kinorhynchs found only in the intertidal zone and the first Pacific Echinoderes living on red macroalgae in inter-tidal pools

Aspidosiphon gracilis Baird 1868

Aspidosiphon gracilis (Baird, 1868) (Fig. 5 D–H) Material. Nha Trang Bay: Tre Island, Dombay Harbor, 10 m depth, tube of Cerianthus filiformis, 1 specimen. Description. Trunk long and thin, 20 mm long, about 2 mm wide, yellow-grey or light brown, with minute papillae; introvert 1.5 X trunk length. Anal shield weakly developed, composed of noncontiguous brown papillae and dark platelets arranged in weakly defined longitudinal rows. Caudal shield light brown, conical, with distinct radial grooves. Unidentate hooks arranged in rings in the distal introvert; proximal part of the introvert with conical hooks. Base of unidentate hooks with bifurcated posterior edge. Retractor muscles originate close to the posterior trunk end, at 5–8 % of trunk length from the caudal shield. Gut with 8–10 loops; spindle muscle attached posteriorly. Nephridia are free, 60 % of trunk length. Discussion. This species varies from other representatives of the subgenus Aspidosiphon (Aspidosiphon) in the structure of both the anal and caudal shields. Aspidosiphon gracilis is a tropical species known from the Indian and Pacific Oceans. It has been found from Australia to the Philippines in the West Pacific. It inhabits coral rocks and mollusk shells in intertidal and shallow water.Published as part of Adrianov, Andrey V. & Maiorova, Anastassya S., 2012, Peanut worms of the phylum Sipuncula from the Nha Trang Bay (South China Sea) with a key to species, pp. 41-58 in Zootaxa 3166 on page 51, DOI: 10.5281/zenodo.27977

Cloeosiphon aspergillus

Cloeosiphon aspergillus (de Quatrefages, 1865) (Fig. 6 C–D) Material. Nha Trang Bay: Mot Island, coral rubble, 7 m, May 2008, 12 specimens; Tre Island, coral rubble, 6 m, Jun 2008, 18 specimens; Tre Island, biofouling, intertidal, Nov 2009, 6 specimens; Mung Island, coral rubble, 12 m, May 2008, 15 specimens; Nok Island, coral rubble, 5 m, 8 specimens; Diamond Bay: coral rubble, intertidal, Jun 2008, 25 specimens; Nov 2009, 16 specimens; Mar 2010, 8 specimens. Description. Trunk up to 70 mm long, 4–5 mm wide, light brown or grey, with minute brown papillae, semitransparent; introvert shorter than trunk. Anal shield consists of white rhomboid or polygonal mosaicly arranged, calcareous units, with a dark central pore; caudal shield absent. Introvert protruded through the center of the anal shield; bidentate hooks arranged in rings distally. Longitudinal musculature continuous; retractor muscles originate in the middle of the trunk. Gut with 10 loops. Nephridia are about 70–90 % of trunk length, completely attached to the body wall. Discussion. This is the only species of the genus Cloeosiphon, and because of its unique configuration between the anal shield and the introvert by far the most distinctive species of sipunculans. This tropical species is widely distributed in the Indo-West Pacific. In the West Pacific it has been reported from Australia to Hainan Island, inhabiting coral rocks in shallow water.Published as part of Adrianov, Andrey V. & Maiorova, Anastassya S., 2012, Peanut worms of the phylum Sipuncula from the Nha Trang Bay (South China Sea) with a key to species, pp. 41-58 in Zootaxa 3166 on page 55, DOI: 10.5281/zenodo.27977

Apionsoma misakianum Ikeda 1904

Apionsoma misakianum (Ikeda, 1904) (Fig. 4 B–D) Material. Nha Trang Bay: Mot Island, 10 m depth, coral rubble and empty bivalve shells, 5 specimens; Mung Island, 25 m depth, muddy sand, 4 specimens; Tre Island, intertidal, fouling community, 3 specimens; Diamond Bay, intertidal, coral rubble, 2 specimens. Description. Trunk spindle-shaped, 2–5 mm long, 0.7 mm wide; posterior trunk with numerous papillae; body wall pale and translucent, muscle layers continuous. Introvert 7–10 X longer than trunk, tentacular apparatus with 5–7 tentacles around the dorsal nuchal organ; hooks with accessory comb of 3–5 basal spinelets. The four retractor muscles originate at the midtrunk area. Gut with 15–20 loops; spindle muscle attached posteriorly. Nephridia bilobed and about 50 % of trunk length. Discussion. In contrast to A. misakianum, A. murinae is characterized by a thick opaque body wall with large trunk papillae, while A. trichocephalus has a considerably long and vermiform body that lacks tentacles and hooks. Apionsoma misakianum is a tropical and subtropical species, widespread in the Atlantic, Indian and Pacific Oceans. This species inhabits coral, sand and algae mats in tidal pools and shallow waters. In the West Pacific it is known from Polynesia to Japan and in the South China Sea from the Hainan Island.Published as part of Adrianov, Andrey V. & Maiorova, Anastassya S., 2012, Peanut worms of the phylum Sipuncula from the Nha Trang Bay (South China Sea) with a key to species, pp. 41-58 in Zootaxa 3166 on page 49, DOI: 10.5281/zenodo.27977

Lihacrosiphon cristatus Sluiter 1902

Lihacrosiphon cristatus (Sluiter, 1902) (Fig. 6 A–B) Material. Nha Trang Bay: Mot and Tre Islands, 4–7 m depth, coral rubble. Description. Trunk 10–15 mm long, 3–4 mm wide, light brown, semitransparent; introvert subequal to trunk length. Anal shield furrowed longitudinally with about 20 grooves and often covered by red, yellow and white calcareous deposit which masks these grooves. Bidentate hooks arranged in rings on the distal introvert; unidentate hooks scattered over the proximal introvert. Longitudinal musculature splits into 15–20 anastomozing bands. Retractor muscles originate 10 % of trunk length from the caudal shield. Nephridia are about 40–45 % of trunk length. Discussion. The species differs from the other representative of this genus, Lithacrosiphon maldivensis, in structure of the anal shield, which is ungrooved, granular, and bullet-shaped in L. maldivensis. Lithacrosiphon cristatus is a tropical species, known from the Atlantic and Pacific Oceans. In the West Pacific it has been reported from Indonesia to southern Japan. It can be found inside coral rocks in shallow water.Published as part of Adrianov, Andrey V. & Maiorova, Anastassya S., 2012, Peanut worms of the phylum Sipuncula from the Nha Trang Bay (South China Sea) with a key to species, pp. 41-58 in Zootaxa 3166 on page 54, DOI: 10.5281/zenodo.27977