Galathea providentia Laurie, 1926

Macpherson, Enrique & Robainas-Barcia, Aymee, 2015, Species of the genus Galathea Fabricius, 1793 (Crustacea, Decapoda, Galatheidae) from the Indian and Pacific Oceans, with descriptions of 92 new species, Zootaxa 3913 (1), pp. 1-335 : 250-253

Galathea providentia Laurie, 1926

( Figs 90 , 119 I)

Galathea providentia Laurie, 1926: 125 , pl. 8, figs 1–4 (type locality: Providence, 92 m, type no longer extant).

Galathea ternatensis .—Baba, 1990: 960 ( Madagascar, 25–115 m).— Tirmizi & Javed, 1993: 83, fig. 37 (stn AB43-63, AB- 22A, and Mozambique Channel, 62–65 m).— Macpherson & Cleva, 2010: 63, color figs 3I, J ( Madagascar, 24–25 m).— Poore et al., 2011: 334, pl. 12D (color photo, Madagascar) (not G. ternatensis De Man, 1902 ).

Material examined. Madagascar, near Nosy Be, 23 m, 30 September 1970: 4 M 2.3–4.2 mm, 7 ov. F 2.4–4.7 mm (MNHN-IU-2013-13786). Between Nosy Be and Nosy Tanikely, 13.4572°S, 48.2484°E, 24–25 m, 21 May 2008: 1 F 4.0 mm (UF12544); 1 M 2.9 mm (UF12548); 1 F 3.4 mm (UF14630). MIRIKY, Stn CP3204, 12°37.03'S, 48°30.3'E, 59–60 m, 29 June 2009: 1 M 4.3 mm (MNHN-IU-2010-1113); 1 M 4.8 mm (MNHN-IU-2010- 1114).—Stn CP3205, 12°37.64'S, 48°25.99'E, 60–63 m, 29 June 2009: 1 ov. F 4.3 mm (MNHN-IU-2010- 1117).—Stn CP3250, 15°22'S, 46°00'E, 493–750 m, 8 July 2009: 1 F 2.5 mm (MNHN-IU-2013-14303).—Stn CP3257, 15°47'S, 44°46'E, crash, no depth, 10 July 2009: 3 M 3.3–4.7 mm, 8 ov. F 2.7–4.6 mm, 3 F 2.8–4.3 mm (MNHN-IU-2010-1321 & 1325 & 1116-1117).—Stn CP3273, 15°29.86'S, 46°03.37'E, 26–34 m, 13 July 2009: 1 M 5.2 mm (MNHN-IU-2010-1020).—Stn CP3280, 14°54.64'S, 46°55.53'E, 57–87 m, 14 July 2009: 1 F 3.6 mm (MNHN-IU-2013-13787).—Stn CP3287, 14°33.69'S, 47°27.93'E, 48–54 m, 15 July 2009: 1 M 4.8 mm, 1 F 2.7 mm (MNHN-IU-2010-1324).—Stn CP3288, 14°31.9'S, 47°26.54'E, 46–54 m, 15 July 2009: 1 ov. F 3.5 mm (MNHN-IU-2013-13788). ATIMO VATAE, Stn CP3512, 25°15'S, 47°17'E, 140–144 m, 29 April 2010: 4 M 3.5–3.7 mm, 1 ov. F 3.8 mm (MNHN-IU-2010-4022).—Stn DW3518, 24°50.7'S, 47°28.7'E, 99–101 m, 30 April 2010: 3 M 3.0– 4.4 mm, 4 ov. F 3.0– 3.6 mm, 1 F 3.1 mm (MNHN-IU-2013-13800).—Stn TB4, 25°02.1'S, 47°00.1'E, 11–12 m, 1 May 2010: 1 F 1.2 mm (MNHN-IU-2013-13795).—Stn DW3530, 24°35.9'S, 47°32.1'E, 80–86 m, 2 May 2010: 2 M 2.8–3.0 mm, 2 F 2.7–2.9 mm (MNHN-IU- 2010-2732).—Stn DW3533, 24°42'S, 47°32'E, 187–209 m, 2 May 2010: 1 ov. F 3.7 mm (MNHN-IU-2013-13801).—Stn CP3538, 25°22.4'S, 47°02.8'E, 89–95 m, 3 May 2010: 1 F 3.6 mm (MNHN-IU-2013-13806).—Stn CP3539, 25°25'S, 47°03'E, 106–114 m, 3 May 2010: 1 F 3.2 mm (MNHN-IU-2013-13805).—Stn CP3545, 25°29'S, 46°42'E, 108–110 m, 4 May 2010: 1 M 3.4 mm, 1 ov. F 3.3 mm, 1 F 4.8 mm (MNHN-IU-2013-13809).—Stn CP3546, 25°22.7'S, 46°42.5'E, 84–85 m, 4 May 2010: 4 M 2.7–3.5 mm, 3 F 3.0– 3.9 mm (MNHN-IU-2013-13808).—Stn CP3547, 25°18.0'S, 46°40.3'E, 69-70 m, 4 May 2010: 12 M 2.7–4.4 mm, 11 ov. F 3.0– 3.5 mm, 10 F 3.6 mm (MNHN-IU- 2010-2731); 1 M 3.0 mm (MNHN- IU-2013-13796); 1 M 4.2 mm (MNHN-IU-2013-13797); 1 F 3.2 mm (MNHN-IU-2013-13798); 1 ov. F 3.4 mm (MNHN-IU-2013-13799).—Stn CP3572, 25°11.7'S, 47°12.5'E, 75–77 m, 8 May 2010: 9 M 2.7–3.6 mm, 2 ov. F 2.4–4.5 mm, 6 F 1.9–3.0 mm (MNHN-IU- 2010-2746); 1 F 3.0 mm (MNHN-IU-2013-13802); 1 M 3.5 mm (MNHN-IU-2013-13803).—Stn CP3579, 25°54.5'S, 45°33.2'E, 65–66 m, 9 May 2010: 1 M 2.5 mm, 1 ov. F 3.4 mm (MNHN-IU-2010-3945).—Stn CP3620, 25°47'S, 46°02'E, 133–178 m, 15 May 2010: 1 M 3.0 mm, 1 ov. F 3.5 mm (MNHN-IU-2013-13804).—Stn CP3624, 25°38.1'S, 45°57.0'E, 63 m, 15 May 2010: 3 M 2.3–3.7 mm, 3 ov. F 2.6–3.7 mm (MNHN-IU-2013-13807).

La Réunion. MD32, Stn CP43, 21°20.7’S, 55°26.9’E, 73–77 m, 18 August 1982: 10 M 2.8–3.6 mm, 13 ov. F 2.7–3.6 mm, 3 F 2.7–2.8 mm (MNHN-IU-2013-13915).—CP55, 21°05.3’S, 55°12.5’E, 97–130 m, 22 August 1982: 1 M 2.6 mm (MNHN-IU-2013-13912).—Stn CP127, 20°52’S, 55°37.1’E, 92 m, 2 September 1982: 13 M 2.9–4.0 mm, 12 ov. F 3.0– 3.9 mm, 3 F 3.5–3.6 mm (MNHN-IU-2013-13913).—Stn CP172, 20°51.8’S, 55°37.7’E, 105–120 m, 8 September 1982: 1 M 2.1 mm (MNHN-IU-2013-13911).—Stn CP174, 20°51.8’S, 55°36.5’E, 78–85 m, 8 September 1982: 1 M 3.4 mm, 3 ov. F 3.5–3.9 mm, 1 F 3.0 mm (MNHN-IU-2013-13914).

Philippines. MUSORSTOM 2, Stn CP47, 13°33'N, 122°10’E, 81–84 m, 26 November 1980: 1 M 4.2 mm (MNHN-IU-2013-13791); 1 M 4.4 mm (MNHN-IU-2013-13792).

South China Sea. Macclesfield Bank, Stn 63, 15°37'2'"N, 114°28'42"E, 63 m, 3 May 1893: 2 M 3.5–3.7 mm ( NHMUK).—Stn 76, 15°55'25"N, 114°21'58"E, 87 m, 9 May 1893: 2 M 3.2–3.6 mm ( NHMUK).—Stn 15, 15°37'N, 113°52'E, 68 m, May 1892: 1 F 4.0 mm ( NHMUK).

Vanuatu. SANTO, Stn CP3549, 25°16.9'S, 46°31.3'E, 53–54 m, 4 May 2010: 1 M 2.5 mm, 1 ov. F 2.8 mm, 2 F 2.0 mm (MNHN-IU- 2010-2735).

New Caledonia. Kenden Island, 20°39.8'S, 164°15.3'E, 49–63 m, 7 October 1993: 2 M 3.2–4.2 mm (MNHN- IU-2013-13792). Koumac, 20°39.8'S, 164°15.3'E, 55 m, 6 October 1993: 2 M 4.3–4.8 mm, 1 ov. F 4.0 mm (MNHN-IU-2013-13790); 1 M 4.4 mm (MNHN-IU-2013-13789). Koumac, 55–60 m, 7 October 1993: 1 M 3.5 mm, 1 ov. F 5.2 mm (MNHN-IU-2013-13794).

Fiji. MUSORSTOM 10, Stn DW1359, 17°49.7'S, 178°47.8'E, 183–188 m, 13 August 1998: 1 ov. F 5.0 mm (MNHN-IU-2013-13917).

Description. Carapace: Slightly broader than long; transverse ridges with dense short setae, and with some scattered long non plumose setae; cervical groove distinct, laterally bifurcated. Gastric region with transverse ridges: 1 epigastric ridge unarmed, uninterrupted, medially convex; 2 protogastric ridges, anterior one medially interrupted, sometimes with minute parahepatic spine on each side, posterior ridge short; 1 mesogastric ridge medially interrupted and not extending laterally to anteriormost of branchial marginal spines; 2 metagastric ridges, anterior one uninterrupted or medially interrupted, not continuing laterally to anteriorbranchial ridges, posterior ridge short. Hepatic region with small spine near first lateral (anterolateral) spine. Anterior branchial region with distinct ridges. Mid-transverse ridge uninterrupted, preceded by shallow cervical groove. Posterior branchial region with 5 or 6 ridges, 0–3 of them uninterrupted. Lateral margins well convex medially, with 7 spines: 2 spines in front of, and 5 spines behind, anterior cervical groove; first anterolateral, well-developed, at same level of lateral limit of orbit, second, small, at midlength between anterolateral spine and anteriormost spine of branchial margin, with small spine ventral to between first and second; 2 spines on anterior branchial region, last small, and 3 spines on posterior branchial margin. Small spine on lateral limit of orbit; infraorbital margin with strong spine. Rostrum 1.8–1.9 times as long as broad, length 0.7–0.8 postorbital carapace length and breadth 0.3 that of carapace; distance between distalmost lateral incisions 0.3 distance between proximalmost lateral incisions; dorsal surface nearly horizontal in lateral view, with numerous small scale-like setose ridges; lateral margin with 4 deeply incised teeth.

Pterygostomian flap rugose, unarmed, ridges with short setae, anterior margin acute.

Sternum: As long as broad, lateral extremities gently divergent posteriorly. Abdomen: Somites 2–4 each with 2 uninterrupted transverse ridges on tergite; somites 5 and 6 each with 2 scale-like ridges. Males with G1 and G2.

Eyes: Ocular peduncles 1.6–1.7 times longer than broad, maximum corneal diameter 0.7 rostrum width.

Antennule: Article 1 with 3 well-developed distal spines, distodorsal larger, distoventral spine slightly smaller than others. Ultimate article with a few short fine setae not in tuft on distodorsal margin.

Antenna: Article 1 with ventral distomesial spine barely reaching distal margin of article 2. Article 2 with 2 distal spines, distolateral spine longer than distomesial, and exceeding midlength of article 3. Articles 3 and 4 unarmed.

Mxp3: Ischium with flexor margins ending in small spine, extensor margin ending in acute angle; crista dentata with 20–22 denticles. Merus as long as ischium; flexor margin with 2 strong subequal spines, sometimes 1 small spine between them; extensor margin ending in acute angle. Carpus unarmed.

P1: 3.0–3.5 times carapace length, with numerous setiferous scales, and some scattered long non-plumose setae. Merus 1.1–1.2 times carapace length, 1.6–2.1 times as long as carpus, with some spines, dorsomesial and distal spines stronger than others. Carpus 0.7–0.9 length of palm, 1.6–2.2 times as long as broad; dorsal surface with some small spines; mesial margin with row of spines, distal second stronger than others. Palm 1.5–2.3 times longer than broad, lateral and mesial margins subparallel; small spines arranged roughly in dorsal, dorsolateral and dorsomesial rows. Fingers 0.9–1.0 times palm length, each finger with two rows of teeth distally spooned; fingers unarmed.

P2–4: long and slender, with some setose striae and sparse long non-plumose setae. P2 1.9–2.2 times carapace length. Meri successively shorter posteriorly (P3 merus 0.9 length of P2 merus, P4 merus 0.7–0.8 length of P3 merus); P2 merus 0.7–0.9 carapace length, 3.0–4.5 times as long as broad, 1.4–1.6 times longer than P2 propodus. P3 merus 2.5–3.5 times as long as broad, 1.0–1.4 times longer than P3 propodus. P4 merus 2.5–3.2 times as long as broad, 1.0–1.2 times longer than P4 propodus. Extensor margin with row of 7–9 proximally diminishing spines on P2–3, 1 distal spine on P4; ventral margins distally ending in strong spine, lateral sides with 1–4 small spines on P4. Carpi with 3–5 spines on extensor margin on P2–3, 1 or 2 distal spines on P4, distalmost smaller than distal second and sometimes absent; lateral surface with 2–5 small spines or acute granules sub-paralleling extensor margin; flexor distal margin acute. Propodi 3.5–5.0 (P2), 3.5–5.0 (P3), 3.8–5.0 (P4) times as long as broad; extensor margin with 0–3 minute proximal spines; flexor margin with 4–6 slender movable spines. Dactyli distally ending in well-curved strong spine, length 0.4–0.6 that of propodi; flexor margin with 3–5 proximally diminishing teeth, terminal one prominent.

Epipods present only on P1.

Coloration. Base color translucent light orange or greenish. Long setae on carapace and abdomen reddish. P1 with tips of fingers whitish. P2–4 with distal white stripes on merus, carpus and propodus.

Remarks. Galathea providentia was originally described by Laurie (1926) from six specimens (including two males, one non-ovigerous female and three ovigerous females, one of the three ovigerous females was disignated as holotype) collected in Providence Island (southwestern Indian Ocean). Unfortunately the types are lost. Based on the description and illustrations of Laurie (1926), however, we believe that the material from Madagascar matches very well with this species. Galathea providentia has been placed in the synonymy of G. ternatensis (Baba 1990; Baba et al. 2008), but, they can be easily differentiated by the extension of the anterior metagastric ridge. In G. p ro v i d e n t i a, that ridge does not extend laterally to the anterior branchial ridge, rather than extending to it in G. ternatensis . This character is constant in all specimens examined. Furthermore, the genetic divergences between the two species are 16.7% (COI) and 6.3% (16S rRNA) and ( Tab. 2 ). However, some specimens exhibit some minor intraspecific morphological variation and genetic divergence. For instance, the rostrum is more slender in some specimens from the Philippines, and the hepatic spines can be minute in some individuals. Furthermore, some specimens from distant localities have a genetic divergence of 3.0–4.0% (COI). These differences can suggest the existence of cryptic species, recommending further studies in order to confirm their taxonomic status.

Galathea providentia is also close to G. boisselierae n. sp. from Philippines to New Caledonia, and G. patriciae n. sp. from Wallis and Futuna. The three species can be distinguished by the following characters:

- The length of the walking legs is different between G. patriciae and G. boisselierae and G. providentia . The P2 merus is more than 4 times longer than broad in G. patriciae and less than 4 times in G. boisselierae and G. providentia . Furthermore, the P2 propodus is equal or more than 5 times longer than broad in G. patriciae , and less than 5 times in G. boisselierae and G. providentia .

- The anterior protogastric ridge is usually medially uninterrupted in G. boisselierae , whereas it is usually medially interrupted in G. providentia .

- Two uninterrupted ridges after the mid-transverse ridge of the carapace in G. boisselierae , instead of at most one uninterrupted ridge in G. providentia .

The genetic divergences between G. providentia and G. boisselierae (no data are available for G. patriciae ) are 7.4% (16S rRNA) and 14.2% (COI). The divergences are always larger among these species and other species of Galathea ( Tab. 2 ).

Distribution. Providence, Madagascar, La Réunion, Philippines, South China Sea (Macclesfield Bank), Vanuatu, New Caledonia, Fiji, 11–209 m (the occurrence at Madagascar, Stn. 3250, 493– 750 m, should be considered with caution, because the depth record significantly departs from the known bathymetrical range of the species).

Figures

FIGURE 90. Galathea providentia Laurie, 1926, male, 4.2 mm, Madagascar (MNHN-IU- 2013 - 13797). A, carapace and abdomen, dorsal view; B, thoracic sternites 3 and 4; C, left part of cephalothorax, ventral view, showing antennular and antennal peduncles, and anterior part of pterygostomian flap; D, ischium, merus and carpus of right Mxp 3, lateral view; E, right P 1, dorsal view; F, right P 2, lateral view; G, right P 3, lateral view; H, right P 4, lateral view. Scale: A, F – H = 1 mm; E = 2 mm; B – D = 0.5 mm.

FIGURE 119. Dorsal view. A, Galathea pilosa De Man, 1888, Papua New Guinea, ovigerous female 4.5 mm (MNHN-IU- 2013 - 1055). B, Galathea pilosa De Man, 1888, Maldives, male 3.6 mm (UF 39675). C, Galathea platycheles Miyake, 1953, Madagascar, female 2.2 mm (MNHN-IU- 2013 - 13822). D, Galathea platycheles Miyake, 1953, Western Australia, ovigerous female 1.9 mm (UF 22402). E, Galathea politula n. sp., Vanuatu, holotype, M 3.5 mm (MNHN-IU- 2013 - 9707). F, Galathea polydora n. sp., Vanuatu, male 3.3 mm, (MNHN-IU- 2013 - 9871). G, Galathea polydora n. sp., Vanuatu, ovigerous female 2.5 mm (MNHN-IU- 2013 - 13476). H, Galathea polyphemus n. sp., French Polynesia, male 4.4 mm (UF 15427). I, Galathea providentia Laurie, 1926, Madagascar, female 3.0 mm (MNHN-IU- 2013 - 13802).