Stenotanais uropedon, Segadilha & Bird & Tavares, 2023
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publication ID |
https://dx.doi.org/10.3897/zse.99.103003 |
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publication LSID |
lsid:zoobank.org:pub:CFCE08BC-6C73-47EA-807D-EB9C3F2547E5 |
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persistent identifier |
https://treatment.plazi.org/id/0EA50F8D-E7F1-434D-A5A1-ED2E28B86E43 |
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taxon LSID |
lsid:zoobank.org:act:0EA50F8D-E7F1-434D-A5A1-ED2E28B86E43 |
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treatment provided by |
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scientific name |
Stenotanais uropedon |
| status |
sp. nov. |
Stenotanais uropedon sp. nov.
Figs 5 View Figure 5 , 6 View Figure 6 , 7 View Figure 7
Material examined.
Holotype: Brazil - São Paulo State • neuter, length 1.7 mm; stn D10 R 3, 5-10 cm; MZUSP 43581.
Paratypes: Brazil - Rio de Janeiro State • 1 neuter (dissected), length 1.7 mm; stn P10 R 3, 5-10 cm; MZUSP 43582 - Santa Catarina State • 1 neuter; stn A8 R1, 0-2 cm; MZUSP 43583 - Paraná State • 1 neuter; stn B9 R 1, 5-10 cm; MZUSP 43584 • 1 neuter; stn B9 R 3, 5-10 cm; MZUSP 43585 - São Paulo State • 1 neuter; stn C8 R 1, 2-5 cm (dissected); MZUSP 43586 • 1 neuter; stn E8 R1, 0-2 cm; MZUSP 43587 • 1 neuter; stn E8 R 3, 2-5 cm; MZUSP 43588 • 1 neuter; stn E10 R 2, 2-5 cm; MZUSP 43589 • 1 neuter; stn E10 R 3, 5-10 cm; MZUSP 43590. - Rio de Janeiro State • 1 juvenile; stn F8 R2, 0-2 cm; MZUSP 43591 • 1 neuter; stn F8 R 2, 2-5 cm; MZUSP 43592 • 1 neuter; stn F9 R 3, 2-5 cm; MZUSP 43593 • 2 neuters; stn G9 R1, 0-2 cm; MZUSP 43594 • 1 juvenile; stn P3 R 2, 2-5 cm; MZUSP 43595 .
Diagnosis.
Neuter. Cheliped fixed finger with two simple setae and one spine on cutting edge and a nearby spine on the distolateral margin of the propodal palm. Pereopods 2-3 carpus with long spine, longer than half length of propodus. Uropod endopod oar-shaped, with article-2 broad and flattened; exopod short, 0.3 × of endopod length; both rami without specialised articulated setae.
Etymology.
From the Greek ‘pedon’ (noun), meaning 'oar, rudder’; alluding to the shape of uropod endopod. The name is a noun in apposition with the generic name.
Description.
Based on neuter holotype (MZUSP 43581) length 1.7 mm and dissected neuter paratype (MZUSP 43582) length 1.7 mm. Body (Fig. 5A View Figure 5 ) slender, about 8.5 × L:W. Cephalothorax elongate 1.7 × L:W, 1.7 × pereonite-1, straight-sided, naked. Pereonites 1-6. All pereonites rectangular, parallel-sided; pereonite-1 0.8 × L:W; pereonite-2 1.3 × L:W; pereonites 3-4 1.2 × L:W; pereonite-5 square, as long as wide; pereonite-6 shortest, 0.5 × L:W. Pleon (Fig. 5A, B View Figure 5 ) short, 0.1 × TBL, about as long as pereonites 5 and 6 combined, with five subequal pleonites, with one minute seta on lateral margins. Pleotelson (Fig. 5B View Figure 5 ) trapezoidal about 0.7 × L:W, 0.4 × pleon, with pointed posterior margin bearing two pairs of simple setae and one of PSS distally.
Antennule (Fig. 5C View Figure 5 ) 0.6 × cephalothorax; article-1 0.5 × TL, 1.9 × L:W, with three middle PSS and one simple and two PSS distally; article-2 1.6 × L:W, 0.6 × article-1, with two simple (one long and one minute) and two distal PSS; article-3 1.1 × L:W, 0.5 × article-2, with simple subdistal seta; article-4 2.4 × L:W, 1.5 × article-3, with aesthetasc and six simple terminal setae. Antenna (Fig. 5D View Figure 5 ) article-1 fused with body; article-2 0.8 × L:W, with one simple distal seta; article-3 1.3 × L:W, naked; article-4 2.7 × L:W, 1.9 × article-3, with one simple medial seta and three simple setae and two distal PSS; article-5 3.0 × L:W, 0.7 × article-4, with one distal seta; article-6 minute with five simple terminal setae.
Labrum (Fig. 5E View Figure 5 ) large, hood-shaped, covered by minute setae on lateral and distal margins. Mandible (Figs 5F, G View Figure 5 ) broken during dissection; left mandible (Fig. 5F View Figure 5 ) with incisor smooth; right mandible (Fig. 5G View Figure 5 ) with at least two teeth on incisor process, molar broken off during dissection. Maxillule (Fig. 5H View Figure 5 ) endite with eight terminal spines (at least two serrate), outer margin with setules; palp broken off during dissection. Maxilla (Fig. 5I View Figure 5 ) ovoid and stout, with one side wider, but large relative to maxilliped. Labium (Fig. 5J View Figure 5 ) with distal corner finely setose.
Maxilliped (Fig. 6A View Figure 6 ) basis with simple seta near articulation with palps, not reaching distal margin of endites; endites unfused, divided into three lobe-like structures, with one seta on distal edge; palp article-1 naked; article-2 with three inner (at least one serrate) and one outer setae; article-3 with three (two long, at least one serrate) inner setae; article-4 with four inner setae and one subdistal outer seta. Epignath not observed.
Cheliped (Fig. 6B View Figure 6 ) calcified; basis attached to cephalothorax by large sclerite with dorsodistal setae; basis with long posterior lobe, not reaching pereonite-1, 3.9 × L:W; merus subtriangular, with one ventral seta; carpus stout 1.4 × L:W, with one ventral seta and one proximal and one dorsodistal setae, carpal shield well developed; propodus stout 0.9 × carpus, 1.6 × L:W, with an outer spine and five setae near dactylus insertion on inner side; fixed finger with two strong serrate spines ventrally; cutting edge with two simple setae and one spine; dactylus slightly shorter than fixed finger.
Pereopod-1 (Fig. 7A View Figure 7 ) coxa with small seta; basis broad 1.8 × L:W, naked; ischium with seta; merus 1.3 × L:W, with ventrodistal seta and long serrate spine not reaching carpus distal margin; carpus 1.2 × L:W, about as long as merus, with ventrodistal long serrate spine, dorsodistal spine and ventral spinules; propodus 2.2 × L:W, 1.6 × carpus, with convex inferior margin with ventrodistal spine and microtrichia, one dorsodistal minute seta; dactylus 1.3 × unguis; together 0.8 × propodus.
Pereopod-2 (Fig. 7B View Figure 7 ) coxa with a small seta (not drawn); basis broad 1.7 × L:W, with large dorsal PSS; ischium with one seta; merus 1.1 × L:W, with a ventrodistal seta and long serrate spine almost reaching carpus distal margin; carpus about as long as wide, about as long as merus, with ventral spinules, two unequal ventrodistal spines (one about half length of propodus) and dorsodistal spine; propodus 2.1 × L:W, 1.6 × carpus, with convex inferior margin with ventrodistal spine and microtrichia, one mid-dorsal simple seta and one dorsodistal minute seta; dactylus 1.1 × unguis, with one seta; together 0.7 × propodus.
Pereopod-3 (Fig. 7C View Figure 7 ) similar to pereopod-2, except basis 1.9 × L:W, naked; dactylus 1.4 × unguis, naked.
Pereopod-4 (Fig. 7D View Figure 7 ) basis about 2.3 × L:W, with large ventral PSS; ischium with two long setae; merus 1.3 × L:W, with two ventrodistal serrate spines; carpus 1.8 × L:W, with one seta and three (one long and two short) distal spines; propodus stout 2.4 × L:W, with two ventrodistal spines and one robust and one minute dorsodistal setae; dactylus long with double row of ventral spines, 2.4 × unguis, together 1.1 × propodus.
Pereopod-5 (Fig. 7E View Figure 7 ) similar to pereopod-4, except basis 1.8 × L:W; ischium with two long setae (only one drawn); carpus 1.2 × L:W, with three distal spines; propodus 2.2 × L:W.
Pereopod-6 (Fig. 7F View Figure 7 ) similar to pereopod-5, except basis 2.7 × L:W, naked; merus 1.4 × L:W; carpus 1.7 × L:W; propodus 2.6 × L:W, with three robust dorsodistal setae; dactylus with larger ventral spines, 2.6 × unguis.
Pleopod (Fig. 7G View Figure 7 ) basal article naked; exopod with at least seven plumose setae on outer margin and one seta on inner margin; endopod with at least ten plumose setae and one more robust proximal seta on outer margin, large gap between most proximal.
Uropod (Fig. 6C View Figure 6 ) rami reflexed; basis 1.4 × L:W, 0.6 × pleotelson, naked; exopod one-articled, 0.3 × endopod, with medial seta and tipped by two stout and one simple setae; endopod two-articled; article-1 with one distal seta; article-2 oar-shaped, with one long medial seta and two PSS and four simple distal setae.
Type locality.
São Paulo State, Brazil; stn D10 R3, -25,94725395, -44,83425777 (1906 m).
Distribution.
Brazil: Santos Basin (Rio de Janeiro, São Paulo, Paraná and Santa Catarina States). Occurring on the lower slopes and the São Paulo Plateau area, ranging from depths of 991-1974 m. Twenty-two individuals of this species were collected, with 41% of them found in the 5-10 cm sediment layer (i.e. up to 50-60 × their body length) and 32% at a depth of 2-5 cm.
Remarks.
This new species resembles S. hamicauda from the NE Atlantic by the oar-shaped uropod, but is different from it by: (1) cheliped fixed finger with two simple setae and one spine on cutting edge (three simple setae in S. hamicauda ); (2) pereopods 1-3 dactylus 1.3 × unguis (about as long as in S. hamicauda ); (3) uropod endopod oar-shaped (in S. hamicauda the exopod is oar-shaped); and (4) exopod short, 0.3 × endopod length (in S. hamicauda exopod reaching about 0.8 × endopod length).
Stenotanais uropedon sp. nov. differs from S. leonardoi by its oar-shaped uropod endopod, with the article-2 broad and flattened (with short exopod, 0.3 × endopod), whereas in S. leonardoi , the exopod is slightly wider than the endopod (0.7 × endopod). Additionally, S. uropedon has pereopods with the merus and carpus having long serrate distoventral spines, which are different from those of S. leonardoi (with simple spines); however, these different forms could have been overlooked by previous authors in other congeneric species.
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