Maera Leach 1814
- Dataset
- Species of the Maera - clade collected from Japan. Part 3: genera Maera Leach, 1814, Meximaera Barnard, 1969 and Orientomaera Ariyama, 2018 (addendum), with a key to Japanese species of the clade (Crustacea: Amphipoda: Maeridae)
- Rank
- GENUS
Classification
- kingdom
- Animalia
- phylum
- Arthropoda
- class
- Malacostraca
- order
- Amphipoda
- family
- Melitidae
- genus
- Maera
discussion
Remarks. Species of this genus can be readily distinguished from the other species in the Maera - clade by the setose dactylus of the gnathopod 2. The dactylus in Clessidra Krapp-Schickel & Vader, 2009 has 3 – 4 setae and those in the other genera have only a single seta. Although Krapp-Schickel (2008 a) included Maera tinkerensis Kunkel, 1910 in the genus, this species was removed to Clessidra (Krapp-Schickel & Vader 2009).
type_taxon
Type species. Cancer (Gammarus) grossimanus Montagu, 1808, monotypy. Emended diagnosis. Body smooth. Head, rostrum obsolescent, lateral cephalic lobe rounded, antennal sinus distinct, anteroventral corner usually produced; eyes usually present, reniform or oval. Antennae slender; antenna 1, peduncular articles 1 – 2 longer than article 3, accessory flagellum with 4 – 11 articles. Mandible, molar developed; palp article length 2> 3> 1 or 2 = 3> 1, article 1 with acute distal tooth or obliquely lengthened. Maxilla 1, inner plate bullet-shaped; palp 2 - articulate. Coxae short; anteroventral corner of coxa 1 produced or rounded, coxae 5 – 6 lobate; gills present on coxae 2 – 6, oostegites present on coxae 2 – 5. Gnathopod 1 smaller than gnathopod 2, subchelate; carpus longer than or subequal to propodus; palm oblique. Gnathopod 2 large in both sexes, symmetrical, subchelate; carpus short, slightly lobate; propodus large, length 1.3 – 2.0 times width; palm slightly or moderately oblique, defined by small tooth, sculptured; dactylus with many setae (=> 8) on anterior margin. Pereopods, dactyli simple or bifid; pereopods 3 – 4 slender; bases of pereopods 5 – 7 rectangular or weakly expanded, each with posterodistal corner square or rounded. Pleonal epimeron 3 with small tooth or projected acutely posteroventrally. Uropods biramous; uropod 1 peduncle with basofacial robust seta, rami subequal, with marginal and distal robust setae; uropod 2 similar to uropod 1, both rami bearing marginal and distal robust setae; uropod 3, rami usually subequal in length, outer ramus 1.0 – 2.6 times length of peduncle, distal margins of rami truncate, with a few to many robust setae, longest seta about 0.1 – 0.9 times length of outer ramus. Telson deeply incised, distal margins of both lobes usually with notch, longest apical seta 0.1 – 0.9 times as long as telson. Included species (19). Maera anoculata Rabindranath, 1983; M. bousfieldi Krapp-Schickel & Jarrett, 2000; M. danae (Stimpson, 1853); M. edwardsi Chevreux, 1927; M. fusca (Bate, 1864); M. grossimana (Montagu, 1808); M. hirondellei Chevreux, 1900; M. irregularis Myers & Nithyanandan, 2016; M. jerrica Krapp-Schickel & Jarrett, 2000; M. loveni (Bruzelius, 1859); M. lucinae Krapp-Schickel, 2004; M. nelsonae Krapp-Schickel & Jarrett, 2000; M. pachytelson G. Karaman & Ruffo, 1971; M. sagamiensis sp. nov.; M. schieckei G. Karaman & Ruffo, 1971; M. similis Stout, 1913; M. sodalis G. Karaman & Ruffo, 1971; M. tenera Sars, 1885; M. umarae García-Madrigal, 2010.