Ciliopagurus tricolor Forest, 1995

Poupin, Joseph & Malay, Maria Celia, 2009, Identification of a Ciliopagurus strigatus (Herbst, 1804) species-complex, with description of a new species from French Polynesia (Crustacea, Decapoda, Anomura, Diogenidae), Zoosystema 31 (2), pp. 209-232 : 216-220

Ciliopagurus tricolor Forest, 1995 ( Figs 1B ; 3B ; 4B ; 6-9 )

Ciliopagurus tricolor Forest, 1995a: 54 , figs 8b, 10b, 12b, 31c, 37e, 40b, 41a, b [type locality: Madagascar, Toliara (Tuléar)].

Pagurus (s.s.) strigatus – Hilgendorf 1879: 820, pl. 2, fig. 8 ( Mozambique, Ibo Island).

Aniculus strigatus – Barnard 1950: 431, fig. 80a [not C. strigatus ( Herbst, 1804) ].

Trizopagurus strigatus – Ribes-Beaudemoulin et al. 2002: 69, photo nº 6 [not C. strigatus ( Herbst, 1804) ].

Trizopagurus sp. – Dérijard 1966: 176; 1968: 1241.

Not Ciliopagurus tricolor – Poupin 2005: 9, 23 (Rangiroa) [= C. galzini n. sp.].

TYPE MATERIAL. — Madagascar, Toliara, intertidal, ovig.

♀ holotype, 6.9 mm ( MNHN Pg 4663) ; 1 ♂ paratype, 8.0 mm ( MNHN Pg 3637) .

SHELLS. — Conidae : Conus rattus Hwass in Bruguière, 1792 Conus ? omaria Hwass in Bruguière, 1792 or C.? episcopatus da Motta, 1982.

MATERIAL EXAMINED. — Somalia. Jasiira (Gesira), 20 km south of Mogadishu, coll. M. Vannini IX-X.1979, 1 ♂ 5.5 mm ( NNML).

Tanzania. Coll. M. Bacescu, 13. V.1974, 2 ♂♂ 6.5-7.3 mm ( MNHN Pg 5426).

Europa I. North reef at low tide, coll. R. Dérijard, IV.1964, 2 ♂♂ 10.1 mm ( MNHN Pg 620).

Madagascar. Toliara (= Tuléar), intertidal, coll. R. von Cosel, 18.XI.1986, 1 ovig. ♀ 6.9 mm (holotype MNHN Pg 4663) ; 2 ♀♀ 4.2-7.5 mm ( MNHN Pg 5427).— Same, intertidal, coll. B. Thomassin, 1 ♂ 8.0 mm (paratype MNHN Pg 3637) ; 1 ♂ 4.9 mm ( MNHN Pg 7761) .

Réunion I. Passe de l’Ermitage, coll. M. Guillaume, I.2007, 1 ovig. ♀ 3.3 mm ( MNHN Pg 7760, DNA H279- EF683565 ).— NE of Cap La Houssaye, 21.0189°S, 55.2381°E, rocky coast with basal bedrocks boulders, 0-4 m, coll. G. Paulay, 14.II.2004, 1 ovig. ♀ 2.9 mm ( UF Crust 5433, DNA H68- EF683561 , photo), 1 ♀ 2.4 mm, 1 ♀ 2.9 mm, 1 sp. in shell ( UF Crust 5422, ♀♀ 2.4 and 2.9 mm, DNA H280- EF683566 , DNA H281- EF683567 ).

MATERIAL EXAMINED FOR COMPARISON. — Ciliopagurus shebae (Lewinsohn, 1969) : Japan. Izu Is. Hachijo-jima I., Nazumado, 25 m, coll. Kato, det. Okuno (reported in Okuno et al. 2006), 25.XI.2000, 1 ♀ 4.6 mm ( CMNH ZC 00872). — Izu-ohshima I., Akino-hama, 30 m, coll. Arima, det. Okuno (reported in Okuno & Arima 2006), 27.II.2004, 1 ♀ 6.4 mm ( ZC 01734), 36 m, 1.IX.2004, 1 ovig. ♀ 6.5 mm ( ZC 02122), 23 m, 1.IX.2004, 1 ♂ 3.9 mm ( ZC 02123), 30 m, 2.IX.2004, 1 ovig. ♀ 5.6 mm ( ZC 02124).

DISTRIBUTION ( Fig. 9 ). — West Indian Ocean, approximately between 2°N- 26°S, 32- 55°E: Somalia (Jasiira reef, Mogadishu); Kenya (Mombassa); Tanzania (Paje reef, Zanzibar Island); Mozambique (Ibo I. and Delagoa Bay); Europa I.; Madagascar (Tuléar = Toliara); Réunion. The species is usually collected from the intertidal to about 5 m, with a single record at 30 m (Mombassa, in Forest 1995a). Forest (1995a: 55, 59) has also reported, with some question, a single specimen from Chagos I., central Indian Ocean but this record must be confirmed by observations of living coloration of more specimens from this place.

DIAGNOSIS. — Ocular peduncles 0.57-0.80 times as long as shield (average 0.67). Distal segment of antennular peduncle 0.21-0.30 times as long as shield (average 0.25). Ocular acicles truncated with 2-5 terminal spines. Chelipeds equal; outer face of palm of chela with 3 complete transverse striae, a posterior stria interrupted in ventral half of the palm, and 2 additional short striae situated in ventral half between striae 1-2 and 2-3. These striae are smooth or with minute spinules. Chela 0.78-1.08 times as long as shield (average 0.88); ratio of height to length 0.64-0.80 (average 0.71); fingers 0.49-0.63 times as long as chela (average 0.54). Main stridulating area with 11 or 12 parallel corneous crests, distally acute; 7th to 8th (from dorsal margin) crests longest, 0.4-0.5 times as long as stridulating area.Merus of cheliped without prominent tubercle on ventral face. Dactyl of third ambulatory leg 0.97-1.22 times as long as propodus (average 1.09). Posterior lobes of telson subequal, unarmed or with 1-3 inconspicuous spines on terminal margins.

COLORATION ( Fig. 1B ). — Antennular and antennal peduncles orangish-red; ocular peduncles orangish-red, cornea pale orange (black on preserved specimens). Chelipeds ( Fig. 3B ) and ambulatory legs ( Fig. 4B ) with composite coloured rings, made of one white bluish median band, flanked by two bright red rings; these composite rings are set against an orange background. Chelipeds with composite rings disposed on meri, carpi, and palms of chelae; fingers of chelae almost uniformly pale orange, without composite coloured rings. Ambulatory legs with composite coloured rings on meri, carpi and propodi; dactyls pale orange without composite coloured rings; terminal claws black. Shield white; live coloration of the abdomen unknown, abdomen uniformly white after three weeks in preservative.

REMARKS

Morphological variations observed on the material examined include unusual armament of the ocular acicle. On the smallest specimen (sl 2.2 mm) of C. tricolor only one terminal spine is present. Identification of juvenile specimens based on this character can sometimes be erroneous because of this variation.

Ciliopagurus tricolor is distinguishable by the absence of coloured rings on fingers of chelae and dactyls of ambulatory legs. In the “ strigatus complex” this character is also observed in C. vakovako . However, the two species can be easily separated by the aspect of the coloured rings disposed on the remaining part of the chelae and ambulatory legs (compare Figs 3B, C and 4B, C ): in C. tricolor the rings are composite, with a bluish white median band flanked by two reds rings; whereas in C. vakovako these rings are uniformly red.

Without the help of coloration Ciliopagurus tricolor is hardly distinct from C. strigatus . Forest (1995a: 58) tentatively used biometric measurements to separate them. He indicated that the dactyl of the chelae is about as long as the palm in C. tricolor versus clearly shorter in C. strigatus and that the dactyl of P3 longer is C. tricolor (P3 dactyl/propodus greater in C. tricolor than in C. strigatus ). However, similar measurements made for this study have failed to confirm the statistical validity of these differences (P<0.05) because of large intraspecific variations (see morphometric results and Table 1). Forest (1995a: 58, fig 37c, e) also indicated the presence of an additional stria on the stridulating apparatus of C. tricolor but this difference is size-related and is not confirmed in this study by careful comparison of similarly-sized specimens of the two species.

By its coloration Ciliopagurus tricolor is closely related to C. shebae (Lewinsohn, 1969) another species in the genus with similar composite coloured rings on the chelae and ambulatory legs. Ciliopagurus shebae was reported by Forest (1995a) in the Western Indian Ocean (Red Sea, Madagascar, Réunion, Seychelles). Its geographic range has recently been extended to Japan ( Minemizu 2000: 132; Kato & Okuno 2001: 75; Okuno & Arima 2006: 32, fig. 2h; Okuno et al. 2006: 149, fig. 2 pl. 2b), with several specimens illustrated in colour. Several of these Japanese specimens were examined during this study for comparison with C. tricolor (see comparison specimens in Material examined). Despite almost identical colour patterns on the chelae and ambulatory legs, the two species can easily be differentiated by: 1) the aspect of ocular acicle usually with 2-5 spines in C. tricolor and 1 (rarely 2 or 3) in C. shebae ; 2) morphometric differences that are statistically significant (P<0.05): shorter ocular peduncle in C. tricolor (mean ratio ocular peduncle length/sl 0.67 vs. 0.82), shorter chelae (mean of chela length/sl 0.87 vs. 1.05), shorter dactyl of P3 (mean ratio of P3 dactyl/ propodus length 1.09 vs. 1.36); and 3) distinct depth ranges, usually 0-5 m for C. tricolor , and 20-90/ 130 m for C. shebae .

In Ciliopagurus the tricolor / shebae species pair is comparable to the vakovako / krempfi pair. In both species pairs the coloration is similar and the first species of each pair ( tricolor , vakovako ) belongs to the “ strigatus complex” while the second ( shebae , krempfi ) is collected deeper with distinct aspect of ocular acicle and longer ocular peduncles and dactyls of P3. The relationships of these two species pairs remains to be elucidated. The structural morphology and life habits (inhabiting narrow-apertured shells) of shallow species suggest they form a distinct evolutionary lineage from the deep forms, while the closely matching colour patterns suggest local relationships between shallow and deep pairs. Sequenceable material of the deep species is needed to robustly solve this problem.

Figures

FIG. 1. — Live colorations: A, Ciliopagurus strigatus (Herbst, 1804), Futuna I., ♂ 7 mm (MNHN Pg 7762); B, C. tricolor (Forest, 1995), Réunion I., ovig.♀ 2.9 mm (UF Crust 5433);C, C. vakovako Poupin,2001, Marquesas Is, holotype ♂ 4.3 mm (MNHN 5896); D, C. galzini n. sp., Tuamotus, holotype ♂ 3.8 mm (UF Crust 10901).

FIG. 3. — Left cheliped colour pattern, outer view: A, Ciliopagurus strigatus (Herbst, 1804), ♂ 3.8 mm, Réunion I. (MNHN Pg 7759); B, C. tricolor (Forest,1995),ovig.♀ 3.3 mm,Réunion I. (MNHN Pg 7760);C, C. vakovako Poupin,2001, holotype ♂ 4.3 mm,Marquesas Is (MNHN Pg 5896); D, C. galzini n. sp., holotype ♂ 3.8 mm (UF Crust 10901). Scale bars: 1 mm.

FIG. 4. — Left third pereiopod colour pattern, outer view: A, Ciliopagurus strigatus (Herbst, 1804), ♂ 3.8 mm, Réunion I. (MNHN Pg 7759); B, C. tricolor (Forest, 1995), ovig. ♀ 3.3 mm, Réunion I. (MNHN Pg 7760); C, C. vakovako Poupin, 2001, holotype ♂ 4.3 mm, Marquesas Is (MNHN Pg 5896); D, C. galzini n. sp., holotype ♂ 3.8 mm (UF Crust 10901). Scale bars: 1 mm.

FIG. 6. — Length of ocular peduncle/shield length. Data from Table 1, means ± 1.00 or 1.96 standard deviation, calculated for species of the strigatus species complex and Ciliopagurus krempfi (Forest, 1952): * indicates a significant difference (ANOVA and paired tests, P<0.05).

FIG. 7. — Maximum likelihood phylogram based on COI mitochondrial DNA sequences. Values above the branches correspond to parsimony bootstraps (left), maximum likelihood bootstraps (middle), and Bayesian posterior probabilities (right).

FIG. 9. — Geographic distributions of the Ciliopagurus Forest, 1995 species included in the “strigatus complex” based on the material examined for this work and literature. Light gray area is the distribution of C. strigatus (Herbst, 1804) (●); dark gray areas are the distribution of C. tricolor (Forest, 1995) (▲) and C. vakovako Poupin, 2001 (★); asterisk (Å) is the distribution of C. galzini n. sp. A doubtful locality for C. tricolor is indicated by “▲?”.