Ampithoe takeuchii, 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 : 773-779

Ampithoe takeuchii sp. nov.

( Figures 25–28 )

Type material

Holotype male, 9 mm, dissected, four slides, AM P.84459, between Ilot Maitre and Croissant Reef, New Caledonia (22 ◦ 19.70 ′ S, 166 ◦ 24.40 ′ E), 10 m, on brown alga Sargassum sp. , 6 November 1995, coll. I. Takeuchi (NCL-28) . Paratype female, 8 mm, dissected, one slide, AM P.84460; eight specimens, AM P.84461; paratypes 15 specimens, AM P.84462; many specimens, AM P.84463, same location as holotype .

Type locality

Between Ilot Maitre and Croissant Reef, New Caledonia (22 ◦ 19.70 ′ S, 166 ◦ 24.40 ′ E) .

Etymology

This species is named in honour of the collector Professor Ichiro Takeuchi.

Additional material examined

New Caledonia: few specimens, AM P.84464, 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.84465, 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); few specimens, AM P.84466, Grand Recif Mbere (22 ◦ 20 ′ 11 ′′ S, 166 ◦ 14 ′ 14 ′′ E), 2.0 m, brown alga cf Sargassum sp. , 4 November 1995, coll. I. Takeuchi (NCL-194).

Diagnosis

Antenna 2 slender, similar to antenna 1; peduncular article 4 longer than article 5. Mandible accessory setal row with five robust setae. Maxilla 1 inner plate with one slender seta; outer plate palp article 2 with four apical robust setae. Gnathopod 1 coxa larger than coxa 2, anterior margin straight, anteroventral corner produced subacute; basis longer than coxa, lined with sparse slender setae, with single anterodistal lobe, rounded, not extending beyond ischium, with four slender setae on the margin; carpus subtriangular, anterior margin with four robust setae; propodus subrectangular, narrow, palm acute, excavate, defined by subquadrate corner with one robust seta. Gnathopod 2 basis longer than coxa, lined with slender setae, anterodistal lobe large, rounded, reaching past the ischium, with five slender setae on the margin; merus anteroventral margin subacute; carpus subtriangular, anterior margin with clusters of slender setae; propodus subrectangular, anterior margin with clusters of long slender setae, anterodistal lobe well-developed and setose, palm subacute, excavate, defined by subquadrate corner with small subacute posterodistal tooth, without robust setae, palm length 0.5 times posterior margin; dactylus subequal in length to palm. Telson apically subacute, with one pair of apical slender setae and three pairs of lateral slender setae.

Description

Based on holotype male, 9 mm, AM P.84459.

Head. Antenna 1 longer than antenna 2; peduncular article 1 subequal to article 2; article 2 length 3 times article 3; article 3 length 0.28 times article 1; primary flagellum incomplete, with at least 28 articles; accessory flagellum absent. Antenna 2 slender, similar to antenna 1; peduncular article 4 longer than article 5; flagellum incomplete with at least 22 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 five robust setae; palp tri-articulate, stout, setose along anterior margin; article 2 with five slender setae; article 3 length twice width. Lower lip outer plate with slit, outer lobe distinctly longer than inner lobe; mandibular lobe with curved margins, apically rounded. Maxilla 1 inner plate with 1 slender seta; outer plate palp well-developed, broad, article 2 with four apical robust setae. Maxilla 2 inner plate narrow; outer plate broader. Maxilliped outer plate with large robust setae.

Pereon. Coxae 1–4 longer than broad. Gnathopod 1 subequal to gnathopod 2; coxa larger than coxa 2, anterior margin straight, anteroventral corner produced subacute, ventral margin with a row of small setules; basis longer than coxa, lined with sparse slender setae, with single anterodistal lobe, rounded, not extending beyond ischium, with four slender setae on the margin; merus anteroventral corner produced, subacute; carpus subtriangular, 1.6 times as long as broad, longer than merus, 0.90 times length of propodus, anterior margin with four robust setae; propodus subrectangular, narrow, length 2.1 times width, palm subacute, excavate, defined by subquadrate corner with one robust seta, palm length 0.4 times posterior margin; dactylus subequal in length to palm, apically subacute, tapering evenly, posterior margin denticulate. Gnathopod 2 coxa ventral margin with a row of small setules; basis longer than coxa, lined with slender setae, anterodistal lobe large, rounded, reaching past the ischium, with five slender setae on the margin; merus anteroventral margin subacute; carpus subtriangular, length 1.8 times width, subequal in length to propodus, anterior margin with clusters of slender setae; propodus subrectangular, length 1.5 times width, with a well-developed setose anterodistal lobe, anterior margin with clusters of long slender setae, palm subacute, excavate, defined by subquadrate corner with small subacute posterodistal tooth, without defining robust setae, palm length 0.5 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 anterior margin with robust setae, medial surface with slender setae; merus subrectangular; dactylus recurved.

Pleon. Epimera 1–3 posteroventral corner narrowly rounded. Uropod 1 long, reaching past uropod 2 peduncle; peduncle length 3.8 times width with 11 robust setae, fringe of slender setae three-quarters length of peduncle, distoventral spine absent; inner ramus longer than outer ramus, with six marginal robust setae; outer ramus with 12 marginal robust setae. Uropod 2 peduncle with four robust setae, distoventral spine absent; inner ramus slightly longer than outer ramus, with 12 marginal robust setae; outer ramus with 13 marginal robust setae. Uropod 3 peduncle 1.5 times as long as broad, twice as long as rami, with six distal robust setae; inner ramus with three lateral and five apical robust setae; outer ramus subequal in length to inner ramus, with two large recurved distal robust setae, a patch of lateral denticles, without a lateral setal fringe. Telson trapezoidal, apically subacute, 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, 8 mm, AM P.84460.

Pereon. Gnathopod 1 coxa ventral margin without setae; basis length shorter than coxa; merus anteroventral lobe weakly produced and rounded; carpus anterior margin with two robust setae; propodus palm weakly convex, palm length 0.5 times posterior margin. Gnathopod 2 basis shorter than coxa; carpus as long as broad, subequal to propodus length; propodus anterodistal lobe absent, palm with shallow excavation, palm defined by rounded corner with one robust seta; dactylus overreaching palm.

Remarks

Ampithoe takeuchii sp. nov. is part of the Ampithoe ramondi Audouin, 1826 complex based on the form of the male gnathopod 2 propodus. In A. takeuchii sp. nov. the gnathopod 1 merus posterodistal corner subacute and propodus palm excavation separates A. takeuchii , as well as A. waialua J. L. Barnard, 1970 within the A. ramondi complex. Ampithoe takeuchii sp. nov. can be differentiated from A. waialua by the presence of lateral robust setae on uropod 3 inner ramus while the later species has no lateral robust setae.

Habitat

Living on brown alga Sargassum sp.

Distribution

New Caledonia (current study).

Figures

Figure 25. Ampithoe takeuchii sp. nov. holotype male 9 mm, AM P.84459; Paratype female, 8 mm, AM P.84460, New Caledonia.

Figure 26. Ampithoe takeuchii sp. nov.holotype male 9 mm, AM P.84459, New Caledonia. Scale bars 0.2 mm.

Figure 27. Ampithoe takeuchii sp. nov.holotype male 9 mm, AM P.84459, New Caledonia. Scale bars 0.2 mm.

Figure 28. Ampithoe takeuchii sp. nov.holotype male 9 mm, AM P.84459, New Caledonia. Scale bars 0.2 mm.