Ampithoe ricaudyana, Peart & Hughes, 2013

Peart, R. A. & Hughes, L. E., 2013, Ampithoid amphipods from the South Pacific: Papua New Guinea, French Polynesia and New Caledonia, Journal of Natural History (J. Nat. Hist.) 48 (13 - 14), pp. 739-861 : 766-773

Ampithoe ricaudyana sp. nov.

( Figures 21–24 )

Type material

Holotype male, 7 mm, dissected, three slides, AM P.83698, Recif Ricaudy , New Caledonia (22 ◦ 18.77 ′ S, 166 ◦ 26.92 ′ E), 1.0 m, brown alga Sargassum sp. , 4 November 1995, coll. A.A. Myers (NCL-21) . Paratype female, 6 mm, dissected, one slide, AM P.83699; paratypes 21 specimens, AM P.83700, same location as holotype .

Type locality

Reef Ricaudy , New Caledonia (22 ◦ 18.77 ′ S, 166 ◦ 26.92 ′ E) .

Additional material examined

New Caledonia: one specimen, AM P.84404, Anse Vata, Pointe Bagay (22 ◦ 18 ′ 14 ′′ S, 166 ◦ 26 ′ 09 ′′ E), 0.3 m, coral rubble, 1 November 1996, coll. A.A. Myers (NCL-11); many specimens, AM P.84405, Recif Ricaudy (22 ◦ 18 ′ 14 ′′ S, 166 ◦ 26 ′ 09 ′′ E), brown alga Sargassum sp. , 4 November 1995, coll. A.A. Myers (NCL-20); few specimens, AM P.84406, between Ilot Maitre and Croissant Reef (22 ◦ 19 ′ 42 ′′ S, 166 ◦ 23 ′ 18 ′′ E), 10 m, brown alga Sargassum sp. , 6 November 1995, coll. I. Takeuchi (NCL-28); few specimens, AM P.84407, off Ilot Maitre (22 ◦ 20 ′ 34 ′′ S, 166 ◦ 25 ′ 26 ′′ E), 20 m, dead coral, 7 November 1995, coll. ORSTOM divers (NCL-40); one specimen AM P.84408, Passe de Boulari, off Recif To (22 ◦ 30 ′ 09 ′′ S, 166 ◦ 26 ′ 26 ′′ E), 30 m, stones encrusted with red alga Lithothamnion sp. , 8 November 1995, coll. ORSTOM divers (NCL-45); one specimen AM P.84409, midway between Ilot des Goelands and Grand Recif Abore (22 ◦ 24 ′ 06 ′′ S, 166 ◦ 20 ′ 54 ′′ E), 11 m, white sands, hydroids and algae, 16 November 1995, coll. I. Takeuchi (NCL-128); few specimens, AM P.84410, Anse Vata, Pointe Bagay (22 ◦ 18 ′ 14 ′′ S, 166 ◦ 26 ′ 09 ′′ E), 0.5 m, brown alga Sargassum sp. , 18 November 1995, coll. I. Takeuchi (NCL-130); two specimens, AM P.84411, Anse Vata, Pointe Bagay (22 ◦ 18 ′ 14 ′′ S, 166 ◦ 26 ′ 09 ′′ E), 0.5 m, brown alga Sargassum sp. , 18 November 1995, coll. I. Takeuchi (NCL-130); few specimens, AM P.84412, Anse Vata, Pointe Bagay (22 ◦ 18 ′ 14 ′′ S, 166 ◦ 26 ′ 09 ′′ E), 0.5 m, brown alga Sargassum sp. , 18 November 1995, coll. I. Takeuchi (NCL-131); three specimens, AM P.84413, Roche Percé, Poé (22 ◦ 00 ′ S, 166 ◦ 00 ′ E), 1–3 m, brown alga Sargassum sp. and Padina sp. from rocky shore, 19 November 1995, coll. J.K. Lowry (NCL-133); few specimens, AM P.84414, Grand Recif Mbere (22 ◦ 19 ′ 54 ′′ S, 166 ◦ 13 ′ 14 ′′ E), coarse sand and rubble from gully, 21 November 1995, coll. J.K. Lowry (NCL-156); few specimens, AM P.84415, Grand Recif Mbere (22 ◦ 19 ′ 54 ′′ S, 166 ◦ 13 ′ 14 ′′ E), dead coral rubble, 22 November 1995, coll. J.K. Lowry (NCL-201); few specimens, AM P.84416, Baie de St Marie (22 ◦ 18 ′ 03 ′′ S, 166 ◦ 28 ′ 08 ′′ E), 13 m, brown dictyotalean alga growing on dead Acropora sp. coral, 29 November 1995, coll. J.K. Lowry (NCL-210); many specimens, AM P.84417, north coast of Lifou, Dokin Village, Loyalty Islands (20 ◦ 42 ′ 09 ′′ S, 167 ◦ 09 ′ 54 ′′ E), 8 m, red alga, 28 November 1995, coll. I. Takeuchi (NCL-232); three specimens, AM P.84418, Baie de Santal, Pointe de Easo, Lifou, Loyalty Islands (20 ◦ 47 ′ 16 ′′ S. 167 ◦ 07 ′ 20 ′′ E), 3 m, green calcareous alga Halimeda sp. , 28 November 1995, coll. I. Takeuchi (NCL- 236); one specimen AM P.84419, west coast of Lifou, Dozip Village, Lifou, Loyalty Islands (20 ◦ 56 ′ 18 ′′ S, 167 ◦ 20 ′ 51 ′′ E), 6 m, steep coral reef, 29 November 1995, coll. I. Takeuchi (NCL-240).

Etymology

Species name is a noun in apposition derived from the type locality.

Diagnosis

Antenna 1 primary flagellum with 31 articles. Antenna 2 slender, similar to antenna 1; flagellum with 19 articles. Mandible accessory setal row with six robust setae (seven on left). Maxilla 1 inner plate with one slender seta; outer plate palp article 2 with five apical robust setae. Gnathopod 1 coxa anterior margin concave, anteroventral corner produced, rounded to subacute, ventral margin with row of small setules; basis longer than coxa, lined with slender setae, with single anterodistal lobe large, round; carpus subtriangular, anterior margin with two robust setae; propodus subrectangular, palm subacute, excavate, defined by a subquadrate corner with a subacute tooth and one robust seta. Gnathopod 2 basis longer than coxa, with sparse slender setae, with single posterodistal lobe large, rounded; carpus elongate, subrectangular; propodus subrectangular, with setose anterodistal lobe, palm acute, entire, defined by small subacute corner with one robust seta, palm length 0.35 times posterior margin; dactylus subequal in length to palm. Telson trapezoidal, apically convex, with one pair of apical slender setae and three pairs of lateral slender setae.

Description

Based on holotype male, 7 mm, AM P.83698.

Head. Antenna 1 longer than antenna 2; peduncular article 1 length 1.2 times article 2; article 2 length 2.5 times article 3; article 3 length 0.28 times article 1; primary flagellum with 31 articles; accessory flagellum absent. Antenna 2 slender, similar to antenna 1; peduncular article 4 longer than article 5; flagellum with 19 articles. Epistome and upper lip angle directed nearly straight down, around 90 degrees. Upper lip distally setose. Mandible molar well-developed, triturating; accessory setal row with six robust setae (seven on left); palp tri-articulate, slender; article 2 with six slender setae; article 3 length 2.1 times width. Lower lip outer plate with slit, outer lobe distinctly longer than inner lobe; mandibular lobe with curved margins, apically subacute. Maxilla 1 inner plate with one slender seta; outer plate palp well-developed, broad; article 2 with five apical robust setae. Maxilla 2 inner and outer plates broad. Maxilliped outer plate with small robust setae.

Pereon. Coxae 1–4 longer than broad. Gnathopod 1 smaller than gnathopod 2; coxa 1 larger than coxa 2, anterior margin concave, anterodistal corner produced, rounded to subacute, ventral margin with row of small setules; basis much longer than coxa, lined with slender setae, with single anterodistal lobe large, round; merus anteroventral corner produced acute; carpus subtriangular, length 1.1 times width, 0.8 times propodus length, anterior margin with two robust setae; propodus subrectangular, length 2.1 times width, palm subacute, excavate, defined by subquadrate corner with subacute tooth and one robust seta, palm length 0.4 times posterior margin; dactylus overreaching palm, apically subacute, tapering evenly, posterior margin denticulate. Gnathopod 2 coxa ventral margin with row of small setules; basis longer than coxa, with sparse slender setae, with single posterodistal lobe large, rounded; merus anteroventral corner produced subacute; carpus elongate, subrectangular, length 3 times width, 1.2 times merus length, 0.9 times propodus length; propodus subrectangular, length 2.4 times width, with setose anterodistal lobe, palm acute, entire, defined by small subacute corner with one robust seta, palm length 0.35 times posterior margin; dactylus subequal in length to palm, apically acute, tapering evenly, posterior margin denticulate. Pereopods 3–4 basis and merus narrow. Pereopods 5–7 basis with marginal robust setae and medial slender setae; merus subrectangular; dactylus recurved.

Pleon. Epimera 1–3 posteroventral corner subquadrate. Uropod 1 long, reaching end of uropod 2 rami; peduncle length 4 times width with 14 robust setae, setal fringe threequarters length of peduncle, distoventral spine absent; inner ramus 0.6 times length of peduncle, longer than outer ramus, with three marginal robust setae; outer ramus with five marginal robust setae. Uropod 2 peduncle with five robust setae, without distoventral spine; inner ramus with six marginal robust setae, slightly longer than outer ramus; outer ramus with eight marginal robust setae. Uropod 3 peduncle length 1.4 times width, with five distal robust setae, 1.7 times rami length; inner ramus with four apical robust setae; outer ramus subequal to inner ramus, with two large recurved robust setae, without lateral setae or denticles. Telson trapezoidal, apically convex, subapical cusps small, with one pair of apical slender setae and three pairs of lateral slender setae.

Female (sexually dimorphic characters)

Description based on paratype, 6 mm, AM P.83699.

Pereon. Gnathopod 1 subequal to gnathopod 2; basis shorter than coxa; carpus length 1.2 times width, without robust setae; propodus palm subacute, subsigmoidal. Gnathopod 2 basis shorter than coxa; carpus subtriangular, length subequal to breadth, 0.85 times propodus; propodus subovate to subrectangular, length 1.5 times width, without anterodistal lobe; dactylus overreaching palm.

Remarks

The male gnathopod 2 elongate carpus in Ampithoe ricaudyana sp. nov. is also seen in A. eremitis Peart ( 2007b) , A. longicarpus ( Appadoo and Myers 2004) and A. maxillissius ( Ledoyer 1984) . In A. ricaudyana sp. nov. and A. eremitis the gnathopod 1 propodus palm is concave with the dactylus overreaching the palm, unlike A. longicarpus and A. maxillissius where the gnathopod 1 palm is convex.

In A. ricaudyana sp. nov. the male gnathopod 2 palm is weakly concave in comparison to the deep excavation seen for A. eremitis . The maxilla 1 palp number of apical robust setae also differs, with five robust setae in A. ricaudyana sp. nov. and nine robust setae in A. eremitis . The uropod 3 inner ramus and peduncle are without lateral robust setae in A. ricaudyana sp. nov. and present on both articles for A. eremitis .

Habitat

This species was found living on the brown alga Sargassum sp. at a depth of 1 m.

Distribution

New Caledonia (current study).

Figures

Figure 21. Ampithoe ricaudyana sp. nov., holotype male 7 mm, AM P.83698; paratype female 6 mm, AM P.83699, New Caledonia.

Figure 22. Ampithoe ricaudyana sp. nov., holotype male 7 mm, AM P.83698, New Caledonia. Scale bars 0.2 mm.

Figure 23. Ampithoe ricaudyana sp. nov., holotype male 7 mm, AM P.83698; paratype female 6 mm, AM P.83699, New Caledonia. Scale bars 0.2 mm.

Figure 24. Ampithoe ricaudyana sp. nov., holotype male 7 mm, AM P.83698, New Caledonia. Scale bars 0.2 mm.