Pycnodontochiton Sirenko, Zhang & Sigwart 2025, gen. nov.
Year: 2025
Type: other
Abstract: Pycnodontochiton Sirenko, Zhang & Sigwart gen. nov. Pycnodontochiton sinensis Sirenko, Zhang & Sigwart. Type species. Diagnosis Chitons of small to medium size with body length up to 19 mm, elongate-oval, valves moderately elevated (dorsal elevation about 0.35). Head valve slightly narrower than tail valve. Valves V and VI widest. Tail valve with anterior mucro. Ratio of length of postmucronal area to length of antemucronal area 1.4. Tegmentum sculptured with small elongated granules closely arranged in longitudinal rows in central areas of intermediate valves and in antemucronal areas of tail valve and in quincunx patterns or in a random manner in other areas. Most granules with 1, 2 or 3 aesthete pores. Perinotum narrow, 5.5 times narrower than valve V, covered with bluntly pointed, slightly flattened, long spicules with 10–12 vague longitudinal ribs around spicule. Marginal needles and ventral spicules with vague longitudinal ribs or smooth. Radula ca. 5 mm long, with about 126 rows of mature teeth; central tooth large and unusual wide, with round dorsal edge, first lateral tooth narrow, roughly L-shaped, major lateral teeth large, with flat elongate heads, first uncinal tooth unusually narrow and elongated, major uncinal tooth long with well-developed blade. Number of gills in adult specimens 22. Etymology The genus name is a combination of the Greek roots pycno - (dense), dont - (tooth) and chiton, referring to the distinct dense tooth rows of the radula in this genus. The Greek word χιτών (chiton) is a masculine noun in the third declension. Distribution Deep-water chemosynthetic habitats from the East China Sea to the South China Sea. Taxon discussion The new genus includes two species: Pycnodontochiton tenuidontus (Saito and Okutani, 1990) comb. nov., found in hydrothermal vent sites in the Okinawa Trough area and P. sinensis gen. et sp. nov., from the Haima cold seep area in the South China Sea, at depths of 1385–1392 m. Although new genus is superficially similar to Leptochiton as considered by Saito and Okutani (1990), it differs significantly from all known species in the teeth of the radula. Really no species of chitons, including species of the genus Leptochiton, have such huge central teeth and such long first uncinal tooth, which undoubtedly confirms the validity of the new genus Pycnodontochiton gen. nov.
Authors: (SOSA), Senckenberg Ocean Species Alliance, Andrade, Luiz F., Boyko, Christopher B., Brandt, Angelika, Buge, Barbara, Dávila Jiménez, Yasmín, Henseler, Mats, Hernández Alcántara, Pablo, Jóźwiak, Piotr, Knauber, Henry, Marcondes Machado, Fabrizio, Martínez-Muñoz, Carlos A., Momtazi, Farzaneh, Nakadera, Yumi, Qiu, Jian-Wen, Riehl, Torben, Rouse, Greg W., Sigwart, Julia D., Sirenko, Boris, Souza-Filho, Jesser F., Steger, Jan, Stępień, Anna, Tilic, Ekin, Trautwein, Bianca, Vončina, Katarzyna, Williams, Jason D., Zhang, Junlong
Institutions: Senckenberg Research Institute and Natural History Museum Frankfurt/M, University of Łódź, Hofstra University, Goethe University Frankfurt, Muséum national d'Histoire naturelle, Universidad Nacional Autónoma de México, Instituto de Ciencias del Mar y Limnología, Universidade Estadual de Campinas (UNICAMP), Hong Kong Baptist University, Scripps Institution of Oceanography, University of California San Diego, Zoological Institute, Universidade Federal de Pernambuco, University of Vienna, Senckenberg - Leibniz Institution for Biodiversity and Earth System Research, Chinese Academy of Sciences, Institute of Oceanology
Language: English
Subfield: Oceanography
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7091700739
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