Leucothoe enko
| Notice: | This page is derived from the original publication listed below, whose author(s) should always be credited. Further contributors may edit and improve the content of this page and, consequently, need to be credited as well (see page history). Any assessment of factual correctness requires a careful review of the original article as well as of subsequent contributions.
If you are uncertain whether your planned contribution is correct or not, we suggest that you use the associated discussion page instead of editing the page directly. This page should be cited as follows (rationale):
Citation formats to copy and paste
BibTeX: @article{White2012ZooKeys173, RIS/ Endnote: TY - JOUR Wikipedia/ Citizendium: <ref name="White2012ZooKeys173">{{Citation See also the citation download page at the journal. |
Ordo: Amphipoda
Familia: Anamixidae
Genus: Leucothoe
Name
Leucothoe enko White & Reimer, 2012 sp. n. – Wikispecies link – ZooBank link – Pensoft Profile
Type material
Holotype male, 1.6 mm RUMF-ZC-1850, Omonawa, Tokunoshima Island, Kagoshima, reef wall (27°53'29"N, 128°56'10"E), among coral rubble, 21 m, K.N. White and N.S. White, col., 21 September 2010 (KNWTokuno3B). Paratype female, 1.7 mm, RUMF-ZC-1851, Toguchi Beach, Okinawa–jima Island, Okinawa, patch reef (26°21'47"N, 127°44'12"E), among coral rubble, 1–2 m, K.N. White and N.S. White, col., 20 October 2010 (KNWOkinawa14C).
Type locality
Omonawa, Tokunoshima Island, Kagoshima, Japan (27°53'29"N, 128°56'10"E).
Additional material examined
1 specimen, RUMF-ZC-1852, KNWTokuno3B; 4 specimens, NSMT-Cr 21993, KNWOkinawa24C; 1 specimen, RUMF-ZC-1853, KNWOkinawa24C; 1 specimen, NSMT-Cr 21994, KNWOkinawa71B.
Diagnosis (male)
Head anterior margin oblique, produced, distal margin excavate with rounded projection. Maxilla 1 palp 1–articulate, margins constricted. Gnathopod 1 propodus proximally inflated: dactylus reaching 0.1 × propodus length. Gnathopod 2 basis distally expanded, stout; propodus palm concave with 6 large tubercles. Pereopods 5–7 bases narrowly expanded, posterior margins serrate.
Description (male)
Head. Anterior margin oblique, produced, anterodistal margin rounded, distal margin excavate with rounded projection; ventral cephalic keel anterior produced, excavate; anteroventral margin quadrate, ventral margin excavate; eyes present with more than 10 ommatidia, round. Antenna 1 0.3 × body length, flagellum 6–articulate, peduncle article 1 width less than 2 × article 2, accessory flagellum absent. Antenna 2 0.3 × body length, subequal in length with antenna 1, flagellum 4–articulate. Mandibular palp ratio of articles 1–3 1.0: 2.4: 0.6, article 2 with 3 distal setae, article 3 with two distal setae, incisors weakly dentate; left mandible with 5 raker spines, lacinia mobilis large, weakly toothed; right mandible with 5 raker spines, lacinia mobilis small, weakly toothed. Upper lip asymmetrically lobate, anterior margin weakly setose. Lower lip inner lobes fused, setose; outer lobes with moderate gape, anterior margins setose. Maxilla 1 palp 1–articulate, margins constricted with 3 distal slender setae; outer plate with 5 distal robust setae. Maxilla 2 inner plate with 4 distal slender setae outer plate with 3 distal slender setae. Maxilliped inner plates distal margin rounded with v-shaped indentation, with short simple robust setae; outer plate inner margin smooth, reaching 0.2 × palp article 1, with simple marginal setae, facial setae present; palp article 4 subequal in length with article 3, distally acute.
Pereon. Coxae 1–4 relative widths 1.0: 1.1: 0.9:1.0. Gnathopod 1 coxa smooth, bare, anterodistal margin produced, rounded, distal margin straight, posterior margin excavate, facial setae absent; basis distally expanded, anterior and posterior margins bare; ischium bare; carpus linear, distal length 9.1 × width, proximal margin dentate, distal margin with 4 long setae; propodus proximally inflated, palm dentate with 4 distal setae; dactylus smooth, reaching 0.1 × propodus length. Gnathopod 2 coxa broader than long, subequal in size with coxa 3, smooth, bare, anterior margin straight, anterodistally rounded, distal margin rounded, posterior margin straight, facial setae absent; basis distally expanded, stout, anterior margin with 3 setae, posterior margin bare; ischium bare; carpus 0.5 × propodus length, curved, distally tapered, anterior margin smooth; propodus with 1 mediofacial setal row above midline, reaching 0.7 × propodus length, without submarginal setae, posterior margin smooth, palm concave with 6 major and 3 minor tubercles; dactylus curved, proximal margin smooth, bare, anterior margin distally acute, reaching 0.6 × propodus length. Pereopod 3 coxa length 1.2 × width, anterodistal corner overriding distal face of coxa 2, not extending below it, smooth, bare, anterior margin straight, distal margin slightly rounded, posterior margin straight, facial setae absent. Pereopod 4 coxa smooth, bare, anterior margin straight, distal margin rounded, posterior margin straight, facial setae absent. Pereopods 5–7 coxae facial setae absent; bases width length ratios 1: 2.2, 1: 1.9, 1: 1.8, posterior margins serrate, bare. Pleon. Epimera 1–2 with ventral setae, epimeron 3 bare, posteroventral corner subquadrate. Uropods 1–3 relative lengths 1.0: 0.6: 0.9. Uropods 1–2 peduncles 0.8 × inner rami lengths, outer rami 0.6 × inner rami lengths. Uropod 1 inner ramus with 2 robust setae, outer ramus with 1 robust seta. Uropod 2 inner and outer rami each with 1 robust seta. Uropod 3 peduncle and inner ramus 0.7 × inner ramus length; inner and outer rami bare. Telson 1.8 × longer than wide, apex rounded.
Female (sexually dimorphic characters)
Gnathopod 1 basis anterior margin with 3 short setae; carpus distal margin with 7 long setae. Gnathopod 2 basis anterior margin with 3 distal tubercules, with 3 short and 2 medium setae, posterior margin with 1 short seta; propodus with 2 rows of submarginal setae, palm 5 major tubercles; dactylus reaching 0.7 × propodus length.
Etymology
After the Japanese word ‘enko’, meaning ‘arc’ and referring to the concave gnathopod 2 propodus palm (pronounced en-koh).
Ecology
Host unknown, presumably living in sponges in coral rubble.
Relationships
Leucothoe enko sp. n. fits into a distinct group of small species sharing a proximally inflated gnathopod 1 propodus and very strong dentition on the propodus palm of gnathopod 2. These species include Leucothoe adelphe White & Thomas, 2009, Leucothoe micronesiae Barnard, 1965, and Leucothoe minuscula Schellenberg, 1938. Leucothoe enko sp. n. differs from these species in having the maxilla 1 palp 1–articulate with margins constricted, a proximally dentate gnathopod 1 carpus and propodus, posteriorly serrate pereopods 5–7 bases, and telson with a rounded apex.
Remarks
Leucothoe enko sp. n. is deep yellow in color with a small red eye (Figure 15C). This species is endemic to the central Ryukyu Islands. Upon further examination, this group of species may prove to be a part of a cryptic species complex, with different species inhabiting similar niches at different locations.
Distribution
East China Sea: Okinawa–jima Island (Okinawa), Okinoerabu–jima Island and Tokunoshima Island (both Kagoshima), Japan.
Original Description
- White, K; Reimer, J; 2012: Commensal Leucothoidae (Crustacea, Amphipoda) of the Ryukyu Archipelago, Japan. Part III: coral rubble-dwellers ZooKeys, 173: 11-50. doi
Images
|
