Research Article |
Corresponding author: Eknarin Rodcharoen ( eknarin_r@yahoo.com ) Academic editor: Tammy Horton
© 2017 Eknarin Rodcharoen, Niel L. Bruce, Pornsilp Pholpunthin.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Rodcharoen E, Bruce NL, Pholpunthin P (2017) Cirolana phuketensis, a new species of marine isopod (Crustacea, Isopoda, Cirolanidae) from the Andaman Sea coast of Thailand. ZooKeys 695: 1-17. https://doi.org/10.3897/zookeys.695.13771
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Cirolana phuketensis sp. n. was collected from coral rubble from the Andaman sea coast of Thailand. C. phuketensis sp. n. is described and fully illustrated; C. phuketensis sp. n. can be recognized by the presence of transverse sutures on pereonites 2–4, pereonite 7 having three transverse sutures forming a nodulose ridge, antennula peduncle with articles 1 and 2 fully fused; pleotelson dorsal surface with 2 sub-median longitudinal carinae, each of which has one prominent tubercle, lateral margins weakly convex, and posterior margin narrow and rounded; 6 molariform robust setae pereopod 1 on inferior margin of merus and the penial openings are two low tubercles. A dichotomous key to species of Cirolana in Thailand is given.
Isopoda , Cirolanidae , Cirolana , new species, the Andaman Sea, Thailand
Thailand lies in the tropical zone between Pacific Ocean and Indian Ocean. This region has high marine biodiversity (
The family Cirolanidae Dana, 1852 (superfamily Cirolanoidea, suborder Cymothoida following
Species of Cirolana Leach, 1818 primarily occupy marine and estuarine habitats, and the genus is the largest in the family (
Cirolana phuketensis sp. n. is described from the Andaman coast of Thailand and a key of Cirolana species occurring in Thai coastal waters is provided.
Specimens were collected from shallow-water coral-rubble habitats (at depths of 0–10 m) in the coastal zone of the Andaman Sea (Figure
Appendages of a paratype were dissected for description under Olympus SZ51 stereo microscope and drawn under an Olympus CH30 compound microscope with a camera lucida. The holotype dorsal and lateral drawings are based on photos taken by Olympus DP71 microscope digital camera with Olympus SZH10 stereo microscope. Drawings were inked using Adobe Illustrator with Wacom Bamboo drawing tablet. Morphological characters for the descriptions follow
Abbreviations:
For the most recent accounts of this genus in Thai waters see
Holotype: ♂ (5.0 mm), Ao Makham, Phuket Province, 07°49'51"N, 98°24'14"E, 6 August 2014, trapped in 1 m of depth, coral rubble, coll. E. Rodcharoen (
Paratypes: 6 ♂ (4.6, 5.8, 5.2, 5.0, 5.3, 5.1 mm [dissected]), 3 ♀ (5.2, 4.9, 4.9 mm [dissected]), same data as holotype, (
Body 2.8 times as long as greatest width, widest at pereonite 6, lateral margins subparallel (Figure
Antennula (Figure
Frontal lamina (Figure
Mandible molar process (Figure
Pereopod 1 (Figure
Penes (Figure
Pleopod 1 (Figure
Uropod peduncle (Figure
Pereonite 7 without transverse row of tubercles. Pleonites 4–5 and pleotelson with low tubercles.
Adult males (n = 13) 4.6–5.8 mm (mean 5.1 mm); females (n = 16) 4.6–5.7 mm (mean 5.1 mm).
Pleotelson (n = 28 [12 ♂ and 16♀]) with 5–6 RS, with 6 RS (3+3) most frequent (92%). Uropod endopod mesial margin with 6–7 RS, with 6 (82%) and 8 (4%) occurring only once, lateral margin with 1 RS (96%) and 2 (4%) occurring only once; exopod mesial margin with 2–4 RS, with 4 most frequent (92%), 2 and 3 occurring only once (3%), lateral margin with 5– 6 RS, with 5 most frequent (92%).
Cirolana phuketensis sp. n. is characterized by pereonites 2–4 each with a single transverse suture; pereonites 5–6 each with 2 transverse sutures; pereonites 7 with 3 transverse sutures that also form a nodulose ridge; antennula peduncular articles 1 and 2 fused; pleotelson dorsal surface with 2 sub-median longitudinal carinae, each of which has one prominent anterior tubercle, lateral margin weakly convex and posterior margin narrow rounded; pereopod 1 merus inferior margin with 6 molariform RS; penes in the form of two low tubercles.
Cirolana phuketensis sp. n. belongs to a group of species within Cirolana that is characterised by dorsal is characterised by dorsal nodular ornamentation on the pereon, pleon and pleotelson (
In the South-East Asian region there are few similar species, although undescribed species are known. Cirolana phuketensis sp. n. differs from C. tuberculata from southern Philippines (see
This species is also similar to Cirolana grumula Bruce, 1994 (Papua New Guinea) and the Australian species Cirolana oreonota Bruce, 1986. However, there are many characters that differentiate Cirolana phuketensis sp. n. from these species. Cirolana phuketensis sp. n. can be separated from C. grumula by having antennula articles 1 and 2 fused (vs unfused in C. grumula); pleotelson dorsal surface with 2 sub-median longitudinal carinae, each of which has one prominent tubercle (vs each of which has two prominent tubercles), pleotelson lateral margin weakly convex (vs straight) and posterior margin narrow rounded (vs subtruncate); pereopod 1 merus inferior margin has 6 molariform RS (vs 5 molariform RS); penes has 2 low tubercles (vs opening flush with surface of sternite 7. Cirolana phuketensis sp. n. differs from C. oreonota by pereonites 2–4 with transverse sutures (vs without transverse sutures on pereonites 2–4); pleotelson dorsal surface with two prominent ridges each with one anterior submedian tubercle (vs ridges not prominent each with 3 of submedian tubercles), pleotelson lateral margin weakly convex (vs straight), posterior margin narrow rounded (vs sub truncate) with 6 RS (vs 8 RS); antennal flagellum extending to middle of pereonite 4 (vs extending to anterior of pereonite 3); pereopod 1 merus inferior margin having 6 molariform RS (vs 5 molariform RS); penes 2 low tubercles (vs opening flush with surface of sternite 7).
1 | Epimera of pleonites 3 and 4 not produced and medially indented | C. rachanoi |
– | Epimera of pleonites 3 and 4 produced and medially not indented | 2 |
2 | Body dorsal surfaces without tubercles; rostral point present, folded ventrally and posteriorly, in contact with frontal lamina; uropodal rami apically bifid | 3 |
– | Body dorsal surfaces with tubercles; anterior margin of head with or without rostral point; uropodal rami apically not bifid | 7 |
3 | Posterior margin of pleotelson with 12–14 RS; endopod of pleopods 3–4 distinctly smaller than exopod, without marginal plumose setae | C. songkhla |
– | Posterior margin of pleotelson with 6–10 RS; endopod of pleopods 3–4 about equal to or slightly smaller than exopod, with marginal plumose setae | 4 |
4 | Antennula peduncle with articles 1 and 2 fused; male pereopod 1 without setal fringe; penial opening separated by 3% of sternal width; uropod peduncle ventrolateral margin with 1 sensory seta | C. andamanensis |
– | Antennula peduncle with 4 unfused articles; male pereopod 1 with setal fringe; penial opening separated by 12–13% of sternal width; uropod peduncle ventrolateral margin with 3 sensory setae | 5 |
5 | Pleonite 3 with posterolateral margins extending to but not beyond posterior margin of pleonite 5; pleopod 1 endopod with lateral margin concave, appendix masculina 1.4 times as long as pleopod endopod | C. phangnga |
– | Pleonite 3 with posterolateral margins extending clearly beyond posterior margins of pleonites 4 and 5; pleopod 1 endopod with lateral margin straight, appendix masculina ≤ 1.6 times as long as pleopod endopod | 6 |
6 | Uropodal rami apices equally bifid; appendix masculina lateral curved , 1.6 times as long as pleopod endopod | C. siamensis |
– | Uropodal rami apices with lateral process prominent; appendix masculina straight, 1.9 times as long as pleopod endopod | C. thailandica |
7 | Endopod of pleopods 3–4 distinctly smaller than exopod, without marginal plumose setae; found in brackish water habitats | 8 |
– | Endopod of pleopods 3–4 with marginal plumose setae; about equal to or slightly smaller than exopod; found in marine habitats | 9 |
8 | Anterior margin of head without rostral point; frontal lamina anterior margin rounded | C. fluviatilis |
– | Anterior margin of head with rostral point, folded ventrally and posteriorly, in contact with frontal lamina; frontal lamina pentagonal | C. willeyi |
9 | Head weakly produced and overriding the antennules/a bases; inferior margins of pereopods 6 and 7 serrate | C. bruscai |
– | Head not produced and overriding the antennules/a bases; inferior margins of pereopods 6 and 7 not serrated | C. phuketensis sp. n. |
The first author would like to thank Dr. Bongkot Wichachucherd Department of Science, Faculty of Liberal Arts and Science, Kasetsart University, Kamphaeng Saen Campus, for helping to collect the samples. We are grateful to the Department of Aquatic Science and Department of Biology, Prince of Songkla University for access to the laboratory facilities. This work was financed through the Higher Education Research Promotion and National Research University Project of Thailand, Office of the Higher Education Commission, Prince of Songkla University. This is contribution number 195 from the NWU-Water Research Group.