Taiwanese Leucothoidae (Crustacea: Amphipoda), Including Three New Species from Dongsha Atoll. Author White, Kristine N. The University of Tampa, Biology, 401 W. Kennedy Blvd., Tampa, FL 33606 U. S. A. Author Machida, Ryuji J. The University of Tampa, Biology, 401 W. Kennedy Blvd., Tampa, FL 33606 U. S. A. & Biodiversity Research Center, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529 Taiwan. & The University of Tampa, Biology, 401 W. Kennedy Blvd., Tampa, FL 33606 U. S. A. text Zoological Studies 2018 2018-09-27 57 47 1 22 http://dx.doi.org/10.6620/ZS.2018.57-47 journal article 10.6620/ZS.2018.57-47 1810-522X PMC6517761 31966287 12825927 F347BCBB-F9D5-4A2B-8A01-8CB1183889A9 Leucothoe batillum sp. nov. ( Figs. 3F , 4-5 ) urn:lsid:zoobank.org:act: 4884D455-66F6-4FDE-84E7- A77F1D08D94A Material Examined : Holotype : male, 4.3 mm , NMMB-CD 5583 KNW-Dongsha-2017-1d, Dongsha Atoll north beach, 20°42'18.26"N , 116°43'43.290"E , 1.5 m , 29 May 2017 , K.N. White collector . Paratype : female, 4.1 mm , NMMB-CD 5584, same station data as Holotype . Other : 1 male , 1 female , 1 juvenile ; ASIZCR000421, KNW-Dongsha-2017-3f, Dongsha Atoll lagoon, 20°42'14.76"N , 116°48'17.2074"E , 11 m ; 21 May 2017 ; K.N. White, collector. 4 females , 1 juvenile ; KNW-Dongsha-2017-12d, Dongsha Atoll south beach, 20°47'57.48"N , 116°43'24.07"E , 1.7 m ; 27 May 2017 ; K.N. White, collector. Etymology : From the Latin ‘ batillum ’ meaning ‘shovel, fire pan’ and referring to the shovel-like gnathopod 2 carpus in males of this species, used as noun in apposition. Diagnosis : Head anterior margin round. Ventral cephalic keel anterior margin excavate, anteroventral margin quadrate with a simple cusp. Eyes oval ( Fig. 4A ). Accessory flagellum present, 1-articulate ( Fig. 4B ). Gnathopod 1 dactylus reaching 0.2 × propodus length ( Fig. 4C ). Gnathopod 2 carpus distally truncate, resembling a shovel, serrate; propodus with one mediofacial setal row slightly displaced toward midline ( Fig. 4F ). Telson apex evenly rounded ( Fig. 5B ). Description (male holotype ) : Head: Anterior margin rounded, anterodistal margin evenly rounded; ventral cephalic keel anterior margin excavate, anteroventral margin quadrate with a simple cusp, ventral margin oblique; eyes with more than 10 ommatidia, oval. Antenna 1 0.3 × body length, flagellum 7-articulate, peduncle article 1 width slightly wider than article 2 ( Fig. 4A ), accessory flagellum present, 1-articulate ( Fig. 4B ). Antenna 2 0.2 × body length, shorter in length than antenna 1, flagellum 3-articulate ( Fig. 4A ). Mandibular palp ratio of articles 1-3 1.0:3.2:2.0, article 2 with 6 marginal setae, article 3 with 2 distal setae, incisors weakly dentate ( Fig. 5F ); left mandible with 13 raker spines, lacinia mobilis large, weakly toothed ( Fig. 5E ); right mandible with 13 raker spines, lacinia mobilis small ( Fig. 5F ). Maxilla 1 palp 2-articulate, with 4 distal slender setae; outer plate with 6 distal robust setae and 3 slender setae ( Fig. 4H ). Maxilla 2 inner plate with 7 marginal and distal robust setae, outer plate with 3 distal robust setae and several slender marginal setae ( Fig. 4G ). Maxilliped inner plates distal margin rounded, with short simple robust setae; outer plate inner margin smooth, reaching 0.4 × palp article 1; palp article 4 thick, subequal in length with article 3, distally acute ( Fig. 5G ). Pereon : Coxae 1-4 relative widths 1.0: 1.2: 0.8: 1.4 ( Fig. 4A ). Gnathopod 1 coxa anterodistal margin produced with notch, distal margin straight, posterior margin concave; basis distally slightly expanded, anterior margin with 3 short setae, posterior margin bare; ischium bare ( Fig. 4C ); carpus curved, distal length 9 × width, distally very narrow, smooth, anterior margin with small short setae ( Fig. 4E ); propodus straight, palm dentate with short setae; dactylus smooth, reaching 0.2 × propodus length ( Fig. 4D ). Gnathopod 2 coxa subquadrate, wider than coxa 3, smooth, margins slightly rounded; basis slightly distally expanded, anterior margin with 4 short setae, posterior margin with 1 distal seta; ischium with 1 distal seta; carpus 0.4 × propodus length, curved, setose, distally truncate, resembling a shovel, serrate; propodus with one mediofacial setal row slightly displaced to midline, reaching 0.8 × propodus length, submarginal setal row of 6 setae, anterior margin gently curved, smooth, palm with 5 medium tubercles; palmar corner clearly defined as prominent hump, remaining posterior margin straight; dactylus curved, proximal margin smooth, bare, anterior margin distally acute, reaching 0.6 × propodus length ( Fig. 4F ). © 2018 Academia Sinica, Taiwan Fig. 4. Leucothoe batillum sp. nov. male holotype, scale bars represent 0.1 mm; (A) Habitus; (B) Antenna 1 enlarged; (C) Gnathopod 1 medial; (D) Gnathopod 1 propodus enlarged; (E) Gnathopod 1 carpus enlarged; (F) Gnathopod 2 medial; (G) Maxilla 2; (H) Maxilla 1. © 2018 Academia Sinica, Taiwan Fig. 5. Leucothoe batillum sp. nov. male holotype and female paratype, scale bars represent 0.1 mm; (A) male telson; (B) male telson enlarged; (C) female Gnathopod 2 medial; (D) female Gnathopod 2 carpus lateral; (E) male left Mandible; (F) male right Mandible; (G) male Maxilliped; (H) female Gnathopod 1 medial. © 2018 Academia Sinica, Taiwan Pereopod 3 coxa smooth, anterior margin rounded, distal margin rounded, oblique, posterior margin straight. Pereopod 4 coxa smooth, anterior margin expanded, distal margin straight, posterior margin convex. Pereopods 5-7 bases width length ratios 1: 1.1, 1: 1.1, 1:1.0, posterior margins bare; pereopods 5-6 bases posterior margins smooth, pereopod 7 basis posterior margin serrate ( Fig. 4A ). Pleon : Epimeron 1 anterodistal margin with 1 seta; Epimeron 2 distal margin with 3 setae; Epimeron 3 bare, posteroventral corner rounded ( Fig. 4A ). Uropods 1-3 relative lengths 1.0: 0.6: 0.8. Uropod 1 peduncle 1.3 × inner ramus length, outer ramus 0.9 × inner ramus length; inner and outer rami each with 3 robust setae. Uropod 2 peduncle 0.9 × inner ramus length, outer ramus 0.7 × inner ramus length; inner and outer rami each with 2 robust setae. Uropod 3 peduncle subequal in length with inner ramus, outer ramus 0.8 × inner ramus length; inner and outer rami each with 2 robust setae ( Fig. 4A ). Telson 2.1 × longer than wide ( Fig. 5A ), apex rounded, beset with four short setae ( Fig. 5B ). Female paratype (sexually dimorphic characters) : Gnathopod 1 basis anterior margin with six short setae ( Fig. 5H ). Gnathopod 2 carpus distally tapered, smooth, not spoon-like; propodus palm with 3 small tubercules ( Fig. 5C ). Color pattern : When alive this species has yellow antenna 1 peduncle articles 1 and 2, a red-orange striped “saddle” pattern on pereonites 2-5, and a red dot coxa 4 ( Fig. 3F ). Ecology : This species was collected among Halimeda and coral rubble. Relationships : Leucothoe batillum sp. nov. resembles Leucothoe assimilis Barnard, 1974 , Leucothoe epidemos White and Thomas, 2009 , Leucothoe makromatos White and Thomas, 2009 , Leucothoe tarte Barnard, 1974 , and Leucothoe trulla White and Reimer, 2012a in having a round anterior head margin, a long gnathopod 1 dactylus, and a truncate gnathopod 2 carpus. The shovelshape of the gnathopod 2 carpus is unique to L. batillum sp. nov. , with the carpus of all of the other species being more fluted or spoon-like. The displaced mediofacial setal row on gnathopod 2 propodus is shared with L. makromatos and L. trulla . The other species listed here have a mediofacial setal row above the midline. The rounded telson found in L. batillum sp. nov. is not shared by any of these species, with a blunt simple telson in L. assimilis and a tridentate tip found in the other species. Distribution : Dongsha Atoll, Taiwan (present study).