Agononida madagascerta, Poore, Gary C. B. & Andreakis, Nikos, 2014

Poore, Gary C. B. & Andreakis, Nikos, 2014, More species of the Agononida incerta complex revealed by molecules and morphology (Crustacea: Decapoda: Anomura: Munididae), Zootaxa 3860 (3), pp. 201-225 : 211-213

Agononida madagascerta n. sp.

( Fig. 2 f, 6)

Material examined. Holotype. MADAGASCAR. Between Nosy-bé and Banc du Leven: 12°46'S, 48°11'E, 430–488 m (MIRIKY stn CP3223), MNHN IU- 2013-7976 (male, 19 mm).

Paratypes. MADAGASCAR, collected with holotype: MNHN IU- 2010-1159* (4 ovigerous females, 15–18 mm; male, 16 mm; 5 juveniles, 7–11 mm). Between Nosy-bé and Banc du Leven: 12°31'S, 48°15'E, 415–416 m (MIRIKY stn CP3190), MNHN IU- 2010-1150* (ovigerous female, 16 mm); 12°38'S, 48°14'E, 420–436 m (MIRIKY stn CP3183), MNHN IU- 2009-1891* (ovigerous female, 16 mm).

Diagnosis. Telson anterolateral margin with a strong triangular notch at 70% of length, anterior section with a thin upturned concave margin, smooth over anterior third and denticulate over posterior two-thirds; posterior section thickened, denticulate, oblique anteriorly and squarish posteriorly. Pereopods 2–4 with dactyli about 8 times as long as greatest basal width; robust setae on flexor margin of dactylus of pereopod 2 number 3–11 (median 7); of pereopod 3, 0–2 (median 1); and of pereopod 4, 0–1. Pereopod 4 merus without spines proximally on upper face.

b c

d e Description. Adult male. Holotype, cl. 20 mm. Carapace 0.90 times as long as greatest width. Gastric region with pair of small epigastric spines. Frontal margin inclined posteriorly at 18° from midline. Rostrum spiniform, 0.6 length of carapace (both measured from base of supraocular spines); supraocular spine 0.5 length of rostrum (both measured from base of rostrum). Thoracic sternite 3 0.5 width of sternite 4; midlength of sternal plastron (sternites 4–7) 0.6 width of sternite 7. Telson greatest width 1.5 times midlength; anterolateral margin with a strong triangular notch at 70% of length, anterior section with a thin upturned concave margin, smooth over anterior third and denticulate over posterior two-thirds; posterior section thickened, denticulate, oblique anteriorly and squarish. Eye with maximum corneal diameter 0.94 basal width of supraocular spines. Maxilliped 3 ischium 0.6 times as long as merus.

Pereopod 1 (cheliped) of slender adult form, 4.4 times as long as carapace, merus 1.3 times as long as carapace, carpus 0.5 times as long as merus, propodus 1.4 times as long as merus, fingers 0.5 times as long as total propodus length. Merus with 1+5 spines along upper margin, 1+6 spines along mesial face, 1+14 spines along lateral face, with distal spine only on lower margin; carpus with 1+2 spines on upper margin, 1+2 spines on mesial face, 1+1 spines on lateral face; propodus oval in cross-section, with 3 spines on upper margin, with 1+2 spines along mesial face, with 2 spines on lateral face near base of dactylus, without spine on lower margin; dactylus cutting edge with ridge of c. 50 uneven teeth, few more prominent than others.

Pereopod 2 3.5 times carapace length, merus 1.3 times carapace length, 7.6 times a long as greatest width, carpus 0.28 times as long as merus, propodus 0.64 times as long as merus, dactylus 0.5 times as long as propodus; merus with 1+11 spines along extensor margin, with 1+6 spines along flexor margin; carpus with 1+1 spines along extensor margin; dactylus sinusoidal on extensor margin, 8 times as long as greatest basal width, with row of 7 robust setae distal to heel of flexor margin.

Pereopod 3 3.6 times carapace length, merus 1.3 times carapace length, 7.0 times a long as greatest width, carpus 0.27 times as long as merus, propodus 0.75 times as long as merus, dactylus 0.5 times as long as propodus; merus with 1+13 spines along extensor margin, with 1+6 spines along flexor margin; carpus with 1+1 spines along extensor margin; dactylus, 8.5 times as long as greatest basal width, with 2 robust setae distal to heel of flexor margin.

Pereopod 4 3.6 times carapace length, merus 1.2 times carapace length, 7.2 times a long as greatest width, carpus 0.3 times as long as merus, propodus 0.9 times as long as merus, dactylus 0.5 times as long as propodus; merus with 1+10 spines along extensor margin, with 1+6 spines along flexor margin, without spines on upper face; carpus with 1+2 spines along extensor margin; dactylus, 7.5 times as long as greatest basal width, without robust setae distal to heel of flexor margin.

Ovigerous female, cl. 18 mm, MNHN IU-2010-1159. Pereopod 1 (cheliped) of slender adult form; merus with 1+6 spines along upper margin, 1+4 spines along mesial face, 1+13 spines along lateral face, without spine on lower margin; carpus with 1+2 spines on upper margin, 1+3 spines on mesial face, 1+1 spines on lateral face; propodus oval in cross-section, with 3 spines on upper margin, with 1+3 spines along mesial face, without spines on lateral face, with 2 spines on lower margin.

Pereopod 2 merus with 1+15 spines along extensor margin, with 1+8 spines along flexor margin; carpus with 1+1 spines along extensor margin; dactylus with row of 3 and 6 robust setae distal to heel of flexor margin.

Pereopod 3 merus with 1+15 spines along extensor margin, with 1+8 spines along flexor margin; carpus with 1+1 spines along extensor margin; dactylus with 1 and 0 robust seta distal to heel of flexor margin.

Pereopod 4 merus with 1+11 spines along extensor margin, with 1+6 spines along flexor margin, without spines on upper face; carpus with 1+1 spines along extensor margin; dactylus without robust setae distal to heel of flexor margin.

Variation. The anterolateral margin of the telson of the holotype is more deeply notched than in other individuals but it is obvious to some degree in all (e.g., ovigerous female in Fig. 6 f).

Colour. From photo of paratype, MNHN IU-2009-1891. Carapace red anteriorly, remaining carapace and abdominal somites 1–3 generally orange. Pereopods 1–4 meri with red spots and irregular distal red band, carpus with few red tinges, propodus with proximal and distal red bands; dactylus on pereopod 2 white, on pereopod 3 with white band at midlength, on pereopod 4 all red. Antennal flagellum red except distally.

Etymology. From Madagascar, type locality and incerta , original species in this complex.

Distribution. North-west Madagascar, c. 13°S; 415–488 m (median 444 m) depth.

Remarks. Agononida madagascerta is a new addition to the Agononida incerta -complex and was initially suggested by the molecular analyses. This species is recovered basal to clade B and is highly genetically differentiated from the remaining species in this clade ( Fig. 1 ).

Agononida madagascerta co-occurs with A. africerta in Madagascar but can be distinguished from it by colour and having fewer robust setae on the dactyli of pereopods 2 and 3 (3–11 and 0–1 respectively vs 12–23 and 2–9 respectively in A. africerta ). All individuals possess a strong notch on the anterolateral margin of the telson whereas most individuals of A. africerta lack a notch (see discussion under the latter species).

Agononida madagascerta could be confused with A. norfocerta from the south-western Pacific. The anterior section of the anterolateral margin of the telson of A. madagascerta is slightly but evenly concave, flat and barely tuberculate whereas in A. norfocerta it has a slight concavity anteriorly, is clearly upturned, and more tuberculate. The dactyli of pereopods 2–4 are similar in both species and have overlapping numbers of robust setae. Agononida indocerta has a more prominent posterior section on the anterolateral margin of the telson and possesses facial spines on the merus of pereopod 4.

Figures

FIGURE 1. Distribution (based on 189 museum records) of ten species of the Agononida incerta complex in the Indo-West Pacific, largely in the Southern Hemisphere, separated into two clades, A and B; overlaid by a model-constrained maximumlikelihood phylogeny inferred from 6 COI and 5 16 S new sequences merged with previously produced molecular data. Bootstrap support values for species are given. Species of clade A – A. africerta, yellow circle (12); A. indocerta, red triangle (18); A. polycerta, blue square (4); A. vanuacerta, white triangle (2). Species of clade B – A. auscerta, black asterisk (11); A. incerta, blue square (20); A. madagascerta, black triangle (3); A. rubrizonata, red triangle (34); A. tasmancerta, white square (8). Numbers of records are in parentheses. A. tasmancerta does not appear in the phylogeny. Agononida incerta is likely to occur further north than these records indicate, as far as central Japan.

FIGURE 2. Colour photographs of living animals by T. - Y. Chan unless otherwise noted. a, Agononida africerta, paratype, Mozambique, MNHN IU- 2008 - 10190; b, A. auscerta, PNG, MNHN IU- 2011 - 2426; c, A. incerta, Taiwan (from Baba et al. 2009 and Poore & Andreakis 2012); d, A. indocerta, Western Australia, D. Evans (from Jones & Morgan 2002 and Poore & Andreakis 2012); e, A. madagascerta n. sp., paratype, Madagascar, MNHN IU- 2009 - 1891; f, A. norfocerta, PNG, MNHN IU- 2011 - 891; g, A. polycerta n. sp., French Polynesia, TARASOC stn DW 3377 (specimen not located), L. Corbari; h, A. rubrizonata, paratype, Taiwan (from Poore & Andreakis 2012); i, A. tasmancerta, New South Wales (specimen not located), Image # 741 reproduced from 35 mm slide courtesy of The Neville Coleman Collection.

FIGURE 6. Agononida madagascerta n. sp. Holotype, male, 20 mm, MNHN IU- 2013 - 7976: a (top row, telson and detail of anterolateral margin); b, pereopod 1, dorsal and lateral views; c – e, dactyli of pereopods 2 – 4 (with robust setae magnified). Paratype, ovigerous female, 18 mm, MNHN IU- 2010 - 1159: f, anterolateral margin of telson (line drawings to same scale).