Crustacea: Tanaidacea) from Japan, with the Description of a New Species of Nototanoides

Species Diversity 18: 245–254 Nototanaids from Japan 245 25 November 2013 DOI: 10.12782/sd.18.2.245 Nototanaids (Crustacea: Tanaidacea) from Japan, with the Description of a New Species of Nototanoides Keiichi Kakui1,3 and Hiroshi Yamasaki2 1 Department of Natural History Sciences, Faculty of Science, Hokkaido University, N10 W8, Sapporo 060-0810, Japan E-mail: [email protected] 2 Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan 3 Corresponding author (Received 10 July 2013; Accepted 30 October 2013) We describe a new nototanaid, Nototanoides ohtsukai sp. nov., based on specimens from the Yaku-Shin-Sone Bank, Nansei Archipelago, southern Japan (North Pacific Ocean). This species differs from its only congener, N. trifurcatus Sieg and Heard, 1985, in having a short distal article in the antennule and in the position of a row of aesthetascs on that article. We also present a partial redescription of the nototanaid Paranesotanais longicephalus Larsen and Shimomura, 2008 and a key to the genera of the families Nototanaidae and Tanaissuidae. Key Words: Nototanaidae, Nototanoides, Paranesotanais, Tanaissuidae, new species, key, Japan. been collected from Iriomote and Amami-Oshima Islands Introduction (Fig. 1B; Kakui et al. 2010; Kakui unpubl. data). The other is Paranesotanais longicephalus Larsen and Shimomura, 2008 The family Nototanaidae consists of seven genera and (the only species in its genus), which was described from a eleven species (Anderson 2013). Except for the species of shallow subtidal bottom around Aka Island, Kerama Islands Stachyops and Nototanais, nototanaids have generally been (Fig. 1B; see Larsen and Shimomura 2008). reported from tropical and subtropical regions (Fig. 1A; In 2008 and 2011 we collected specimens of a nototanaid Sieg 1980, 1986; Sieg and Heard 1985; Larsen 2005; Larsen species from depths of 155–201 m on the Yaku-Shin-Sone and Shimomura 2008; Kakui et al. 2010; Araújo-Silva and Bank, Nansei Archipelago, southern Japan. This proved to Larsen 2012; Bamber 2012; Bird 2012b; Esquete et al. 2012; be an undescribed species of Nototanoides, and we describe Kakui and Angsupanich 2012; this study). Two nototanaids it here. In addition, we provide a partial redescription of P. are known from Japan. One is Nesotanais ryukyuensis Kakui, longicephalus to confirm several character states that were Kajihara and Mawatari, 2010, which was described from a unclear in the original description. Finally, we present a key brackish habitat on Okinawa Island and which has also to the genera of the closely related families Nototanaidae Fig. 1. Maps showing nototanaid distributions. A, global distribution of nototanaids, including the sampling sites for Nototanoides ohtsukai sp. nov.; B, nototanaid records in Japan, with the sampling sites for Nototanoides ohtsukai sp. nov. Symbols: red diamonds, Nototanoides; green triangles, Nesotanais; blue circles, Nototanais; black circles (1–4), Gamboa, Birdotanais, Paranesotanais, and Stachyops, respectively. © 2013 The Japanese Society of Systematic Zoology 246 K. Kakui and H. Yamasaki and Tanaissuidae. 4408; BL 1.58, CW 0.23; one vial. Female, ZIHU-4409; BL 2.46, CW 0.30; one vial. Male, ZIHU-4406; BL 2.54, CW 0.37; four slides and one vial. Male, ZIHU-4407; BL 2.11, Materials and Methods CW 0.27; one slide and one vial. Four individuals, ZIHU- 4410; all intact, one vial. Four individuals, NSMT-Cr Specimens of Nototanoides were collected by using a 22361; all intact, one vial. ZIHU-4403–4406, ZIHU-4410, biological dredge during cruises of the R/V Soyo-maru and NSMT-Cr 22361, same collection data as for holo- (National Research Institute of Fishery Science) and TR/V type; ZIHU-4407–4409, TR/V Toyoshio-maru, Yaku-Shin- Toyoshio-maru (Hiroshima University); specimens of Sone Bank, North Pacific Ocean, 29°49.26′N, 130°24.55′E Paranesotanais were collected by scuba from a shallow sub- to 29°48.75′N, 130°24.45′E, 201–198 m depth, biological tidal bottom around Kakeroma Island, Amami Islands (Fig. dredge, 18 May 2011, collected by Susumu Ohtsuka and 1B). The material examined in this study is deposited in the Hiro shi Yamasaki. Zoological Institute, Faculty of Science, Hokkaido Univer- Diagnosis. Relative length of distal article to article 2 sity, Sapporo, Japan (ZIHU), and the National Museum of in antennule 0.42–0.49 in females, 0.38–0.39 in males. Row Nature and Science, Tsukuba, Japan (NSMT). Methods for of aesthetascs on distal article of antennule located on mid- dissecting, preparing, observing, and drawing specimens ventral region. were as described in Kakui and Angsupanich (2012). Ter- Description of female. Based primarily on holotype, minology relevant to orientation and morphology follows with some observations from paratypes ZIHU-4403–4405. the usage of Larsen (2003), except that the term “plumose Body (Fig. 2A, C) dorsoventrally flattened, 6.11 times as sensory seta” (Bird 2011) is used here instead of “broom long as wide. Cephalothorax 0.24 times BL, with one pair seta”. Body length (BL) was measured from the tip of the eye of lateral simple setae posterior to eyes; rostrum blunt- lobe to the tip of the pleotelson; body width was measured triangular; dorsal region of carapace smooth. Pereonites at the widest portion of the cephalothorax (i.e., cephalotho- each with one pair of dorsolateral simple setae; pereonites rax width; CW). Measurements were made axially: dorsally 4–6 each with one pair of lateral simple setae. Pleon 0.27 on the body, antennules, antennae, pleopods, and uropods; times BL. Pleonites as wide as pereon; all similar in shape, laterally on the pereopods. All measurements in the text are each with one pair of dorsolateral simple setae and row of in millimetres unless noted otherwise. The terms “prepara- lateral simple setae. Pleotelson slightly narrower than pleon- tory” (Prep), “ovigerous” (Ovi), and “post-ovigerous” (PO) ites, wider than long, trapezoidal, with one pair each of lat- for females follow the usage of Bird (2011). eral, posteriolateral, and posterior simple setae. Antennule (Fig. 3A, a1) 0.72 times cephalothorax length; Family Nototanaidae Sieg, 1976 length ratio of articles 1–3 3.52 : 1.00 : 0.49. Article 1 with two outer and two inner simple setae and several plumose Diagnosis [after Bird and Larsen (2009)]. Eyes pres- sensory setae. Article 2 with two simple setae and one plu- ent. Pereonites 1–3 not reduced. Female antennule with mose sensory seta. Article 3 with six distal simple setae, three articles. Male mouthparts reduced. Female man- one distal plumose sensory seta, and one distal and four dibular incisors facing inward; right incisor with subdistal mid-ventral aesthetascs. Antenna (Fig. 3B) with six articles; crenulation. Female mandibular molars broad, with heavily length 0.82 times antennule length; length ratio of articles chitinised grinding surface. Cheliped attachment via trian- 1–6 1.00 : 2.16 : 0.81 : 3.98 : 0.52 : 0.11. Article 1 naked. Arti- gular sclerite. Female chelipedal dactylus without dorsal cre- cles 2 and 3 each with one dorsodistal setulate seta. Article 4 nation/nodules. Pereopods 4–6 lacking coxae and clinging with one simple seta and several plumose sensory setae. Ar- apparatus. Uropodal endopod with two articles. ticle 5 with one simple seta. Article 6 with five simple setae. Labrum (ZIHU-4405; Fig. 3C) rounded; distal region set- Genus Nototanoides Sieg and Heard, 1985 ulate; distolateral region with several teeth. Mandibles (Fig. Nototanoides ohtsukai sp. nov. 3D, E) with broad masticatory region bearing several teeth. (Figs 2–5) Left mandible (Fig. 3D) with several teeth on incisor and five teeth on lacinia mobilis; right mandible (Fig. 3E) with Material examined. Holotype. Ovi female, ZIHU-4401; bifurcate incisor. Labium (Fig. 3F) with inner lobe bearing BL 2.75, CW 0.45; five slides and one vial; R/V Soyo-maru, tiny ventrolateral spine; outer lobe well developed, rounded, Yaku-Shin-Sone Bank, North Pacific Ocean, 29°47.0′N, with outer serration. Maxillule (ZIHU-4404; Fig. 3G) with 130°22.6′E to 29°47.6′N, 130°23.0′E, 155–175 m depth, bio- outer clumps of short setae; endite with nine spiniform logical dredge, 2 August 2008, collected by Ken Fujimoto setae. Maxillular palp with two setae at tip. Maxilla (ZIHU- and Takami Morita (sorted by Hironori Komatsu). 4404; Fig. 3G) subovate, naked. Maxillipeds (Fig. 3H, h1, h2, Allotype. Male, ZIHU-4402; BL 2.46, CW 0.39; three I) with bases fused, bearing one ventral simple seta (reach- slides and one vial; same collection data as for holotype. ing beyond distal margin of endite) at insertion of palp. En- Paratypes. PO female, ZIHU-4403; BL 2.70, CW 0.36; dites distally separated; outer margin setulate; each distal four slides and one vial. Ovi female, ZIHU-4404; BL 2.66, margin with one shorter (shorter than 0.33 times longer CW 0.43; four slides and one vial. Ovi female, ZIHU-4405; simple seta length) and one longer simple setae, and two flat BL 2.63, CW 0.36; one slide and one vial. Female, ZIHU- tubercles or “membranous hemispherical structures” (Sieg Nototanaids from Japan 247 Fig. 2. Nototanoides ohtsukai sp. nov. A, C, holotype, female; B, D, allotype. A, B, body, dorsal view; C, D, body, lateral view. Scale bars: 1 mm. and Heard 1985); flat tubercles large, partly overlapping simple seta. Merus triangular, with one ventral simple seta. (Fig. 3h1). Maxillipedal palp (Fig. 3h2) with article 1 naked; Carpus 1.6 times as long as wide, with one dorsoproximal, article 2 with two inner simple setae and one multifurcate one dorsodistal, and two ventral simple setae. Chela with spiniform seta; article 3 with one simple seta and three thick four ventral simple setae. Propodal palm with one outer and bipinnate setae in inner region; article 4 with one subdistal one inner simple setae, and inner row of minute setae at in- simple seta and five inner thick bipinnate setae.

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