Agononida africerta, Poore, Gary C. B. & Andreakis, Nikos, 2012

Poore, Gary C. B. & Andreakis, Nikos, 2012, The Agononida incerta species complex unravelled (Crustacea: Decapoda: Anomura: Munididae), Zootaxa 3492, pp. 1-29 : 10-16

Agononida africerta n. sp.

( Figs 2 D, E, 3C, 8)

? Munida incerta .— Kensley 1977: 162.— Baba 1990: 963 –964.— Tirmizi 1966: 205, fig. 22.

Material examined. Holotype. MOZAMBIQUE. Mozambique Channel. 25°13ʹS, 35°18ʹE, 480–503 m, 10.04.2009 (MAINBAZA stn CP3135), MNHN IU- 2008-10438 (female, cl 22. 4 mm).

Paratypes. MOZAMBIQUE. Mozambique Channel. 23°31ʹS, 35°50ʹE, 446–475 m, 11.04.2009 (MAINBAZA stn CP3142), MNHN IU- 2008-10192 (supermale, cl 31 mm); MNHN IU- 2008-10440 (female, cl 26 mm); MNHN IU- 2008-10441 (female, cl 24 mm); MNHN IU- 2008-10442 (male, cl 17 mm). 24°11.71ʹS, 35°42.3ʹE, 505–506 m, 15.04.2009 (MAINBAZA stn CC3164), MNHN IU- 2008-10435 (female, cl 13.8 mm). 24°11.71ʹS,35° 42.3E, 505–507 m, 15.04.2010 (MAINBAZA stn CC3165), MNHN IU- 2008-10436 (male, cl 15.1 mm). 24°11.71ʹS, 35°42.3ʹE, 505–508 m, 15.04.2011 (MAINBAZA stn CC3166), MNHN IU- 2008-20703. (5, females, cl 6–12 mm; 3 males, cl. 10–17 mm). 25°13ʹS, 35°18ʹE, 480–503 m, 10.04.2009 (MAINBAZA stn CP3135), MNHN IU- 2008- 10191 (female, cl 18 mm); MNHN IU- 2008-10437 (male, cl 18.8); MNHN IU- 2008-20704 (many juveniles, cl ~ 18 mm). 25°12ʹS, 35°17ʹE, 503–505 m, 10.04.2009 (MAINBAZA stn CP3136), MNHN IU- 2008-20705 (3 females, cl 12–24 mm; 2 males, cl 12 mm); MNHN IU- 2008-10190 (female, cl 17 mm); MNHN IU- 2008-10439 (female).

Other material. MADAGASCAR. 12°44.8ʹS, 48°10.6ʹE, 570– 563 m, 0 5.03.1971 (Crosnier stn P1-5), MNHN Ga-685 (3 females; 13 males, cl to 23 mm).

Diagnosis. Telson anterolateral margin sinusoidal, concave and smooth over anterior 60%, remainder sometimes separated by notch, strongly convex, margin almost longitudinal anterior to transverse suture, with crenellate margin. Pereopodal 2–4 dactyli about 6 times as long as greatest basal width, 15–25 (median about 20, 8 exceptional); pereopod 3, 4–9 (median 6); pereopod 4, 1–3. Pereopod 4 merus with 1–4 spines proximally on upper face.

Descriptions. Ovigerous female. Based on MNHN IU2008–10438, cl 22.4 mm. Carapace 0.9 times as long as greatest width. Frontal margin inclined posteriorly at 18° from midline. Rostrum spiniform, 0.45 length of carapace (both measured from base of supraocular spines); supraocular spine 0.65 length of rostrum (both measured from base of rostrum). Thoracic sternite 3 0.48 width of sternite 4; midlength of sternal plastron (sternites 4–7) 0.6 width of sternite 7. Telson greatest width 1.8 times midlength; anterolateral margin sinusoidal, concave and smooth over anterior 60%, remainder separated by notch, strongly convex, margin almost longitudinal anterior to transverse suture, with crenellate margin; lateral margin convex, narrower posteriorly than anteriorly.

Eyes with maximum corneal diameter 0.9 basal width of supraocular spines. Maxilliped 3 ischium 0.6 times as long as merus.

Pereopod 1 (cheliped) of typical adult form, covered with flat squamae fringed with short setae; 3.6 times as long as carapace, merus 0.9 times as long as carapace, carpus 0.7 times as long as merus, propodus 1.9 times as long as merus, fingers 0.5 times as long as total propodus length. Merus with 1+9 spines along upper margin, 4 spines along mesial face, 17 spines along lateral face, with distal spine and 1–3 spine-like squamae on lower margin; propodus spines with marginal spines, with 6 spines on upper margin, with 1+4 spines along mesial face, with 1+3 spine on lateral face near base of dactylus, with 1–3 oblique spines along lower margin plus 1–3 spines on lower lateral face; dactylus cutting edge with ridge of c. 50 denticles.

Minor pereopod 1 with only minor differences.

Pereopod 2 2.9 times carapace length, merus 1.3 times carapace length, 8.8 times a long as greatest width, carpus 0.24 times as long as merus, propodus 0.6 times as long as merus, dactylus 0.6 times as long as propodus; merus with 1+16–20 spines along extensor margin, with 1+8 spines along flexor margin; carpus with 1+1–2 spines along extensor margin; dactylus evenly curved over distal two-thirds, 5.9 times as long as greatest basal width, with row of 20 robust setae distal to heel of flexor margin.

Pereopod 3 2.9 times carapace length, merus 1.3 times carapace length, 7.5 times a long as greatest width, carpus 0.24 times as long as merus, propodus 0.6 times as long as merus, dactylus 0.6 times as long as propodus; merus with 1+16–20 spines along extensor margin, with 1+9–10 spines along flexor margin; carpus with 1+3 spines along extensor margin; dactylus evenly curved over distal two-thirds, 6.1 times as long as greatest basal width, with row of 4 robust setae distal to heel of flexor margin.

Pereopod 4 2.8 times carapace length, merus 1.1 times carapace length, 6.7 times a long as greatest width, carpus 0.3 times as long as merus, propodus 0.7 times as long as merus, dactylus 0.5 times as long as propodus; merus with 1+15–18 spines along extensor margin, with 1+8 spines along flexor margin, merus with 1–4 spines proximally on upper face; carpus with 1+2 spines along extensor margin; dactylus more gently curved than dactyli 2 or 3, distally less setose, 6.1 times as long as greatest basal width, dactylus with 2 robust seta(e) distal to heel of flexor margin.

Male. Based on MNHN IU2008–10437, cl 19.0 mm. Telson anterolateral margin much as in female. Pereopod 1 (cheliped) merus 1.1 times as long as carapace, carpus 0.5 times as long as merus, propodus 1.3 times as long as merus, fingers 0.55 times as long as total propodus length. Merus with 1+8 spines along upper margin, 5–8 spines along mesial face, 14 spines along lateral face.

Pereopod 2 3.6 times carapace length, carpus 0.23 times as long as merus, dactylus 0.7 times as long as propodus; dactylus with row of 25 robust setae distal to heel of flexor margin.

Pereopod 3 3.1 times carapace length, dactylus 0.7 times as long as propodus; dactylus with row of 4 robust setae distal to heel of flexor margin.

Pereopod 4 3 times carapace length, dactylus 0.6 times as long as propodus; dactylus with 3 robust setae distal to heel of flexor margin.

Colour. From photo by T.Y. Chan (MNHN IU-2008-10192, supermale; Fig. 3 C): carapace and abdominal somites 1–4 generally orange, stronger around bases of spines and rostrum. Spines and squamae of pereopods more strongly coloured than elsewhere. Transverse broad orange bands distally on meri of pereopods 1–4, proximally on carpi of pereopods 1–4, subdistally on carpus of pereopod 1, proximally on propodus of pereopod 1, at propodusdactylus articulation of pereopod 1, and along most length of propodi of pereopods 2–4, stronger distally.

Variation. Five of 40 specimens up to cl 31 mm [plus many juveniles] from MAINBAZA samples at MNHN were examined in greater detail. In these, the numbers of robust setae distal to the heel on the flexor margin of the dactyli of pereopods 2–4 vary, even from one side to the other: pereopod 2, 15–22 (8 exceptional, median about 20); pereopod 3, 4–9 (median 6); pereopod 4, 1–2.

Distribution. Off Madagascar and eastern Mozambique, 13°S–25°S; 446– 570 m.

Etymology. africerta , a combination from Africa and incerta .

Remarks. The telson of Agononida africerta differs slightly but consistently from that of the Western Australian species, A. indocerta which is resembles. Whereas in the adult male of A. indocerta the anterolateral lobe of the telson projects strongly and even tapers posteriorly, that of A. africerta is more evenly rounded. The counts of robust setae on the pereopodal dactyli are fewer than in A. indocerta (which has median numbers of 35, 17 and 10 on pereopods 2–4 respectively. The dactyli themselves are narrower and more tapering than in A. indocerta .

These two are the only species in which 1–4 facial spines are usually (but not always) found on the upper surface of the merus of pereopod 4. Both species also, the propodus of the cheliped has 1–3 spines on the lower lateral face, between the spines on the lateral face near the base of the dactylus and the spines on the lower margin. None of these are present in supermales. The coloration of the fresh specimen of A. africerta and the preserved specimens of A. indocerta are similar, in as far as this comparison will allow.

Barnard (1925; 1950) reported Munida incerta from Portuguese East Africa, now Mozambique (25°56´S, 32°52´E), at a depth of 17 m. His description is general and drawing only of the anterior carapace. The occurrence of this species or of A. africerta at this shallow depth is improbable. However, Kensley (1977) also reported M. incerta from 280–454 m off southern Mozambique and Baba (1990) recorded numerous specimens of the same species from Madagascar at 394– 700 m. Tirmizi (1966: 205, fig. 22) provided figures of a specimen off Zanzibar, 421–658 m, but nothing to characterise the species. While none of these been examined by us, it is possible they all referred to A. africerta .

Agononida africerta is genealogically most related to A. indocerta , known records coming from opposite sides of the Indian Ocean. This relationship is supported by shared morphological characters.

Figures

FIGURE 2. Telsons of species of the Agononida incerta complex, with details of the anterolateral margin at twice scale. Scale bar = 10 mm. Agononida incerta: A, male, cl 32 mm, Western Australia, NMV J 56025. B, ovigerous female, cl 24 mm, Western Australia, NMV J 55021. C, supermale, cl 38 mm, Philippines, ZMUC CRU 11555. Agononida africerta: D, male, cl 15.1 mm, MNHN IU- 2008 - 10437. E, female, cl 13.8 mm, MNHN IU- 2008 - 10438. Agononida auscerta: F, male, cl 22 mm, NMV J 62124. G, ovigerous female, cl 24.3 mm, NMV J 55995. Agononida indocerta: H, supermale, cl 30.3 mm, NMV J 62081. I, male, cl 27 mm, NMV J 57295. J, ovigerous female, cl 25 mm, NMV J 57295. Agononida norfocerta: K, male, cl 30.7 mm, MNHN IU- 2011 - 592. L, female, cl 27 mm, NMV J 62814. Agononida rubrizonata: M, male, cl 28.2 mm, Western Australia, NMV J 57292. N, ovigerous female, Western Australia, cl 25 mm, NMV J 57292.

FIGURE 3. Colour photographs of living animals. A, Agononida incerta, Nanfang-ao, Taiwan, T. - Y. Chan (from Baba et al., 2009). B, A. incerta, NMV J 55021, Karen Gowlett-Holmes. C, A. africerta, MNHN IU- 2008 - 10192, T. - Y. Chan. D, A. indocerta, Western Australia, D. Evans (from Jones & Morgan, 2002). E, A. rubrizonata, paratype, Taiwan, T. - Y. Chan. F, A. rubrizonata, Western Australia, NMV J 55029, Karen Gowlett-Holmes.