Agononida norfocerta, 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 : 22-24

Agononida norfocerta n. sp.

( Figs 2 K, L, 11)

Agononida incerta . — Machordom & Macpherson, 2004: 261.

Material examined. Holotype. SOUTHWESTERN PACIFIC, Norfolk Ridge. 23°22.76ʹS 168°51.6ʹE, 980–1000 m, 29.11.1993 (BATHUS 3 stn CP823), MNHN IU- 2011-592 (male, cl 30.7 mm).

Paratypes. SOUTHWESTERN PACIFIC, Norfolk Ridge. 23°19.32ʹS 168°0.31ʹE, 601–608 m, 29.11.1993 (BATHUS 3 stn DW824), MNHN IU- 2008-20706(2 specimens, 16S sequences AY351066 –7 and COI sequences AF283888 –9 det. by E. Macpherson, 2004 as A. incerta ); MNHN IU- 2011-593 (male, cl 23 mm); MNHN IU- 2011-594 (female, cl 29 mm); MNHN IU- 2011-595 (female, cl 23 mm); IU- 2011-596 (female, cl 20 mm); MNHN IU- 2011-597 (female, cl 21 mm); MNHN IU- 2011-598 [now NMV J62814 ] (female, cl 27 mm).

Diagnosis. Telson anterolateral margin with smooth proximal concavity over anterior 70% that ends at sharp step, remainder truncate-convex, margin oblique anterior to transverse suture, with crenellate margin. Pereopodal 2–4 dactyli 5.9–6.2 times as long as greatest basal width, robust setae on dactylus of pereopod 2 number 10–18 (5 exceptional, median 12), of pereopod 3, 1–4 (median 3), and of pereopod 4, 0–3 (median 2). Pereopod 4 merus without spines proximally on upper face.

Descriptions. Supermale. Based on MNHN IU2011-592, male cl 30.7 mm. Carapace as long as greatest width. Frontal margin inclined posteriorly at 16° from midline. Rostrum spiniform, 0.38 length of carapace (both measured from base of supraocular spines); supraocular spine 0.67 length of rostrum (both measured from base of rostrum). Thoracic sternite 3 0.47 width of sternite 4; midlength of sternal plastron (sternites 4–7) 0.6 width of sternite 7. Telson greatest width 1.6 times midlength; anterolateral margin smooth proximal concavity over anterior 70% that ends at sharp step, remainder truncate-convex, margin oblique anterior to transverse suture, with crenellate margin; lateral margin almost straight, more curved proximally and distally.

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 grossly expanded supermale form, slightly asymmetrical, covered with elevated squamae fringed with short setae; 4.7 times as long as carapace, merus 1.4 times as long as carapace, carpus 0.8 times as long as merus, propodus 2.2 times as long as merus, fingers 0.46 times as long as total propodus length. Pereopod 1 (cheliped) merus with 1+6–8 spines along upper margin, with 1+4–6 spines along mesial face, with 1+11–13 spines along lateral face, with distal spine only on lower margin; with 1+2–3 spines on upper margin, with 1+2–5 spines on mesial face, with 1+0–1 spines on lateral face; propodus oval in cross-section, with shallow longitudinal grooves mesially and laterally, palm deeper distally, spines with marginal spines, with 4 spines on upper margin, with 1+2 spines along mesial face, with 1+0 spine on lateral face near base of dactylus, propodus with 1–3 oblique spines along lower margin, without spines on lower lateral face; fixed finger cutting edge with blunt proximal tooth, second tooth proximal to ridge of c. 50 uneven teeth, few more prominent than others, apex bifid; dactylus cutting edge with 2 proximal blunt teeth and ridge of c. 50 uneven teeth, few more prominent than others.

Minor pereopod 1 not differentiated.

Pereopod 2 3.4 times carapace length, merus 1.4 times carapace length, 9.2 times a long as greatest width, carpus 0.22 times as long as merus, propodus 0.5 times as long as merus, dactylus 0.5 times as long as propodus; merus with 1+13–15 spines along extensor margin, with 1+6–7 spines along flexor margin; carpus with 1+2 spines along extensor margin; dactylus evenly curved over distal two-thirds, 5.9 times as long as greatest basal width, dactylus with row of 10 robust setae distal to heel of flexor margin.

Pereopod 3 3.4 times carapace length, merus 1.3 times carapace length, 8.2 times a long as greatest width, carpus 0.26 times as long as merus, propodus 0.6 times as long as merus, dactylus 0.5 times as long as propodus; merus with 1+14–16 spines along extensor margin, with 1+6–8 spines along flexor margin; carpus with 1+1–2 spines along extensor margin; dactylus evenly curved over distal two-thirds, 6.2 times as long as greatest basal width, dactylus with row of 2–3 robust setae distal to heel of flexor margin.

Pereopod 4 3.1 times carapace length, merus 1.1 times carapace length, 6.9 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+11–12 spines along extensor margin, with 1+5–7 spines along flexor margin, merus without spines proximally on upper face; carpus with 1+1–2 spines along extensor margin; dactylus of similar curvature to dactyli 2 and 3, distally less setose, 6.3 times as long as greatest basal width, dactylus with 2–3 robust setae distal to heel of flexor margin.

Female. Based on NMV J62814 ; 3.5 times as long as carapace.

Pereopod 2 3 times carapace length; merus with 1+15 spines along extensor margin, with 1+5 spines along flexor margin; dactylus with row of 10–12 robust setae distal to heel of flexor margin.

Pereopod 3 3.1 times carapace length; merus with 1+12–14 spines along extensor margin, with 1+5 spines along flexor margin; carpus with 1+2 spines along extensor margin; dactylus with row of 1–4 robust setae distal to heel of flexor margin.

Pereopod 4 2.9 times carapace length; merus with 1+10 spines along extensor margin, with 1+6 spines along flexor margin; carpus with 1+3 spines along extensor margin.

Variation. Among the six specimens examined 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, 10–18 (5 exceptional, median 12); pereopod 3, 1–4 (median 3); pereopod 4, 0–3 (median 2).

Distribution. South Western Pacific Ocean, Norfolk Ridge, 23°S, 168°E; 600 m.

Etymology. norfocerta , a combination from Norfolk Ridge and incerta .

Remarks. Six specimens from the one station on the Norfolk Ridge were examined. Two others from the same station were included among the types on the basis of concordant genetic COI and 16S sequences. Abundant material from other south-western Pacific localities identified as A. incerta by Macpherson (1994) has not been examined in detail. He noted geographic variation in cheliped structure, colour and the telson but did not investigate further.

The telson of the male and female are scarcely differentiated in this species. The strong step about two-thirds the way along the anterolateral margin is characteristic

The numbers of dactylar robust setae are variable as in all species but the number on pereopod 2 overlaps the lower numbers of only A. incerta and A. africerta . The anterolateral lobe of the telson of A. incerta has two more or less well defined lobes while A. norfocerta has a single step two-thirds along. The telson of A. africerta has a more longitudinal, rather than oblique, margin on the section anterior to the transverse groove and usually lacks the step. Mitochondrial phylogenies recovered A. norfocerta and A. incerta as sister taxa and genealogically closely related to the A. auscerta + A. rubrizonata subclade.

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.