Metarhachotropis Ariyama & Kohtsuka 2022
Creators
- 1. Osaka Museum of Natural History, Nagai Park, Higashi-Sumiyoshi, Osaka 546 - 0034 Japan.
- 2. Misaki Marine Biological Station, Graduate School of Science, The University of Tokyo, 1024 Koajiro, Misaki, Miura, Kanagawa 238 - 0025 Japan. kohtsuka @ g. ecc. u-tokyo. ac. jp; https: // orcid. org / 0000 - 0003 - 4440 - 2776
Description
Genus Metarhachotropis, new
[Japanese name: Kawari-ryūgūyokoebi-zoku, new]
Type species. Metarhachotropis parva sp. nov. by monotypy.
Diagnosis. Body weakly compressed laterally, smooth. Head massive, rostrum large, eyes present. Antennae subequal, without calceoli, accessory flagellum 1-articulate, flagella short. Mandible, molar poorly triturative. Maxillae reduced, palp of maxilla 1 ordinary, maxilla 2 inner plate broader than outer plate. Coxae very short, coxa 1 strongly produced anteriorly, coxa 4 lacking posterior excavation, coxae 5, 6 bilobed. Gnathopods alike, large, subchelate, not eusirid form; carpi narrow, with posterior lobe; propodi ovate, much longer than carpi, palms oblique. Pereopods slender; pereopods 3, 4 similar, bases narrow; pereopods 5–7 progressively longer, bases expanded. Pleonal epimeron 3 rounded. Uropods biramous, outer rami shorter than inner rami. Telson elongate, cleft.
Etymology. From the Greek meta (= beyond) and Rhachotropis (related genus).
Remarks. Metarhachotropis gen. nov. is characterized by the massive head with large rostrum. Despite the unique body shape, the keys to families in Barnard & Karaman (1991) lead the present specimens to Eusiridae sensu lato owing to (1) head massive but not downturned; (2) accessory flagellum 1-articulate; (3) mandibular palp present, molar well developed; (4) coxae 1–3 almost same length; (5) urosomites separate; (6) uropod 3 biramous, peduncle short, inner ramus not reduced; and (7) telson flat, elongate and cleft. Within the genera of the family, only Eusirella Chevreux, 1908 and Rhachotropis Smith, 1883 [both included in Eusiridae sensu stricto (Lowry & Myers 2017)] resembles this new genus in the very short coxae and the strongly produced coxa 1. However, Metarhachotropis can be distinguished from Eusirella by the large rostrum (small in Eusirella) and the ordinary length of the maxilla 1 palp (short in Eusirella), and from Rhachotropis by the smooth body (carinate or toothed in Rhachotropis).
Included taxa. Metarhachotropis parva sp. nov.
Notes
Files
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Linked records
Additional details
Identifiers
Biodiversity
- Family
- Eusiridae
- Genus
- Metarhachotropis
- Kingdom
- Animalia
- Order
- Amphipoda
- Phylum
- Arthropoda
- Scientific name authorship
- Ariyama & Kohtsuka
- Taxon rank
- genus
- Taxonomic concept label
- Metarhachotropis Ariyama, 2022 sec. Ariyama & Kohtsuka, 2022
References
- Barnard, J. L. & Karaman, G. S. (1991) The families and genera of marine gammaridean Amphipoda (except marine gammaroids). Records of the Australian Museum, Supplement, 13, 1 - 866. https: // doi. org / 10.3853 / j. 0812 - 7387.13.1991.367
- Chevreux, E. (1908) Diagnoses d'Amphipodes nouveaux provenant des Campagnes de la Princesse-Alice dans 1 ' Atlantique Nord. Bulletin de l'Institut Oceanographique, 121, 1 - 15.
- Smith, S. I. (1883) List of the Crustacea dredged on the coast of Labrador by the Expedition under the direction of W. A. Stearns, in 1882. Proceedings of the United States National Museum, 6 (374), 218 - 222. https: // doi. org / 10.5479 / si. 00963801.374.218
- Lowry, J. K. & Myers, A. A. (2017) A phylogeny and classification of the Amphipoda with the establishment of the new order Ingolfiellida (Crustacea: Peracarida). Zootaxa, 4265 (1), 1 - 89. https: // doi. org / 10.11646 / zootaxa. 4265.1