Mayericaprella arimotoi, Guerra-García, 2006

Guerra-García, J. M., 2006, Caprellidae (Crustacea: Amphipoda) from the Great Barrier Reef and Adjacent Localities, Records of the Australian Museum 58, pp. 417-458 : 428-430

Mayericaprella arimotoi n.sp.

Figs 18–22

Type material. HOLOTYPE 3, AM P61561, outer slope, W of “Yoshin Maru Iwaki”, Elizabeth Reef , Australia, 29°57.2'S 159°01.2'E, coral rubble, 8–24 m, st 30, J.K. Lowry & R.T. Springthorpe, 12 Dec 1987 . PARATYPES: 1♀, AM P61562, type locality ; 1♀, AM P61563, type locality; 13 , 2♀♀, AM P61565, reef flat near “Yoshin Maru Iwaki”, Elizabeth Reef , Australia, 29°57.2'S 159°01.2'E, J.K Lowry & R.T. Springthorpe, st 43, 14 Dec 1987 ; 13, AM P61566, large alcove near lagoon entrance, Sound dive site, Middleton Reef, Australia, 29°27.7'S 159°05.4'E, 6 m, P. Hutchings & I. Loch, st 7, 5 Dec 1987 .

Etymology. The species is dedicated to I. Arimoto for his valuable taxonomic studies on the Caprellidae .

Diagnosis. As for the genus.

Description

Holotype male. Body length. 5.2 mm. Lateral view ( Fig. 18A). Body smooth except for a pair of acute projections on the middle of the pereonite 3; head rounded; suture between head and pereonite 1 absent; pereonites 2–5 increasing in size respectively; pereonite 7 the shortest. Gills ( Fig. 18A). Present on pereonites 2–4. Gills on pereonite 2 oval, 2.5 times as long as wide. Gills on pereonites 3 and 4 elongate, length about 4 times width. Mouthparts. Upper lip ( Fig. 19A) symmetrically bilobed, smooth apically. Mandibles ( Fig. 20A,B) without molar; left mandible ( Fig. 20B) with incisor and lacinia mobilis 5- toothed, followed by a row of plates decreasing in size; right mandible ( Fig. 20A) with incisor 6-toothed, lacinia mobilis transformed into a plate minutely serrate distally, followed by row of similar plates decreasing in size; palp 3-articulate, second article with seven setae, distal article with setal formula 1-x-1, being x= 1 in the right mandible and 2 in the left one. Lower lip ( Fig. 19B) with inner lobes well demarcated; outer lobes with some fine and short setulae apically. Maxilla 1 ( Fig. 19D) outer lobe with six robust serrate setae; distal article of the palp with five setae distally and five setae laterally. Maxilla 2 ( Fig. 19E) inner lobe rectangular with five setae; outer lobe rectangular about 1.2 times as long as inner lobe, with six setae. Maxilliped ( Fig. 19C) inner plate with three robust setae and a slender seta; outer plate with eight simple setae; palp four-articulate, dactylus smooth. Antennae. Antenna 1 ( Fig. 21A) about 2 ⁄ 5 body length; flagellum five-articulate. Antenna 2 ( Fig. 21B) about 1 ⁄ 3 length of the antenna 1, scarcely setose; swimming setae absent; flagellum 2-articulate. Gnathopods. Gnathopod 1 ( Fig. 21C) basis as long as ischium, merus and carpus combined; ischium rectangular; merus rounded; carpus trapezoidal; propodus oval, length about 1.5 times width; palm with acute proximal projection with pair of proximal grasping spines, followed by another pair of proximal grasping spines, and two rows of smaller spines along palm; dactylus slightly curved and smooth. Gnathopod 2 ( Fig. 21D) inserted on anterior part of pereonite 2; basis about 1.5 times as long as pereonite 2; ischium and merus rectangular; carpus short and triangular; propodus as long as the basis, length about 2 times width; palm with rows of small grasping spines and a well-developed triangular projection distally; dactylus robust, strongly curved, smooth. Pereopods. Pereopod 3 and 4 absent ( Fig. 18A). Pereopod 5 four-articulate ( Figs 18A, 22A). Pereopods 6 ( Fig. 22B) and 7 ( Fig. 22C) six-articulate; carpus with a grasping spine; propodus with two pairs of proximal grasping spines, followed by a setae, another grasping spine and two setae distally; dactylus of pereopod 7 with a plumose seta. Penes ( Fig. 22D,E) triangular, as long as wide. Abdomen ( Fig. 22D,E) with two pairs of 2-articulate appendages and a dorsal lobe with two plumose setae; a row of setae present between the penes and the appendages.

Paratype female. Body length 3.6 mm. Oostegites ( Fig. 18B) not setose. Projections on pereonite 3 rounded. Gnathopod 2 ( Fig. 21E) with three proximal grasping spines, without triangular projection distally. Abdomen ( Fig. 22F) without row of setae between the penes and appendages.

Remarks. The new species strongly resembles Caprellina bispinosa Müller, 1990 . Nevertheless both species can be easily distinguished by the segmentation of pereopod 5, being 2-articulate in C. bispinosa , and four-articulate in Mayericaprella arimotoi .

Distribution. Presently known from Elizabeth and Middleton Reefs, Tasman Sea.