Pseudozeuxo fischeri, Segadilha & Serejo, 2020
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publication ID |
https://dx.doi.org/10.3897/zse.96.56097 |
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publication LSID |
lsid:zoobank.org:pub:3B79D590-23AB-42EB-9ADD-2DEE0A17C4C7 |
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persistent identifier |
https://treatment.plazi.org/id/869C9E34-5C6F-41CE-8110-FB8CCAAB2712 |
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taxon LSID |
lsid:zoobank.org:act:869C9E34-5C6F-41CE-8110-FB8CCAAB2712 |
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treatment provided by |
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scientific name |
Pseudozeuxo fischeri |
| status |
sp. nov. |
Pseudozeuxo fischeri sp. nov. Figures 8 View Figure 8 , 9 View Figure 9 , 10 View Figure 10 , 11 View Figure 11 , 12 View Figure 12
Material examined.
Holotype: Brazil • 1 ♀ non-ovigerous, TL 1.3 mm ( MNRJ 29867), Stn CR.AN. - C1C, 25 May 2017, Areias Negras, Rio das Ostras, Rio de Janeiro.
Allotype: Brazil • 1 ♂, TL 1.0 mm ( MNRJ 29868), Stn CR.AN. - C1C, 25 May 2017, Areias Negras, Rio das Ostras, Rio de Janeiro.
Paratypes: Brazil • 1 ♀ ovigerous (only oostegites remained), dissected TL 1.2 mm ( MNRJ 29869), Stn CR.AN. - C1C, 25 May 2017, Areias Negras, Rio das Ostras, Rio de Janeiro; Brazil • 2 ♀ non-ovigerous and 1 ♂ ( MNRJ 29870), same station; Brazil • 1 ♀ non-ovigerous ( MNRJ 29871), Stn CR.AN. - C1C, 8 Aug. 2017, Areias Negras, Rio das Ostras, Rio de Janeiro.
Diagnosis.
Female. Pereopods 1-3 coxa with long seta about half as long as basis. Pereopods 2-3 carpus with one ventrodistal seta. Pereopods 4-6 propodus with two spines and one seta ventrally. Uropod endopod article-2 0.8 times as long as article-1; exopod one-articled.
Description.
Based on non-ovigerous ♀ holotype ( MNRJ 29867) and ovigerous (only oostegites remained) paratype ( MNRJ 29869).
Body (Figs 8A View Figure 8 , 9A View Figure 9 ). Length 1.2 mm, 6.7 times L:W, not heavily calcified.
Cephalothorax (Figs 8A View Figure 8 , 9A View Figure 9 ) about 0.2 times of TBL, 2.2 times L:W, narrowing distinctly anteriorly, with two pairs of lateral simple setae (one close to eyes); rostrum triangular; eyes present.
Pereonites 1-6 with length ratio of 0.6:0.8:0.9:1.0:1.0:0.6; pereonites 1, 2, 3 and 6 wider than long, pereonites 3-5 as long as wide; all pereonites with pair of long dorsodistal and short lateral simple setae; pereonite-1 with another pair of minute dorsodistal setae and pereonites 4-6 with pair of long mid-lateral setae.
Pleon (Figs 8A View Figure 8 , 9A-B View Figure 9 ) about 0.08 times of TBL. Pleonites narrower than pereonite-6; all wider than long, similar in shape, but the width gradually narrower from pleonites 1-5; pleonites 1 and 5 with pair of lateral simple setae and pleonite-5 also with two pairs of dorsolateral simple setae.
Pleotelson (Figs 8A View Figure 8 , 9A-B View Figure 9 ) about 0.8 times L:W, pentangular in dorsal view, with pair of lateral simple setae, pair of subdistal and distal penicillate and simple setae.
Antennule (Figs 9A View Figure 9 , 10A View Figure 10 ) shorter than cephalothorax; three-articled. Article-1 3.3 times L:W, outer margin with middle and distal simple and seven penicillate setae; inner margin with two simple setae. Article-2 0.9 times L:W, with penicillate and two simple distal setae. Article-3 2.1 times L:W, with middle and six distal simple setae and subterminal aesthetasc.
Antenna (Fig. 10B View Figure 10 ) shorter than antennule; six-articled. Article-1 naked. Article-2 longer than article-3, with two dorsodistal simple setae. Article-3 with dorsodistal simple seta. Article-4 2.4 times L:W, with middle penicillate seta and two penicillate and two simple distal setae. Article-5 with two distal simple setae. Article-6 with four distal simple setae.
Mouthparts: Labrum (Fig. 10C View Figure 10 ) rounded, finely setose. Mandibles (Fig. 10D-E View Figure 10 ) with molar broad, well developed. Incisor of left mandible (Fig. 10D View Figure 10 ) with several teeth; lacinia mobilis smooth. Incisor of right mandible (Fig. 10E View Figure 10 ) bifurcate distally, with dorsal crenulation. Maxillule (Fig. 10F View Figure 10 ) with endite bearing eight distal spines and fine long setules; palp broken during dissection. Maxilla (Fig. 10G View Figure 10 ) oval, naked. Labium (Fig. 10H View Figure 10 ) bilobed; inner and outer lobes setulate.
Maxilliped (Fig. 10I View Figure 10 ). Bases fused proximally, each bearing simple seta at insertion of palp. Endites not fused, reaching distal margin of palp article-1, each with long pinnate outer seta and two big gustatory cusps in ventrodistal region. Palp article-1 naked; article-2 with four simple inner setae; article-3 with five simple inner setae; article-4 with six distal simple setae. Epignath not recovered.
Cheliped (Fig. 11A View Figure 11 ) attached via small sclerite. Basis short, slightly longer than wide. Merus with ventral simple setae. Carpus stout, 1.3 times L:W, with three simple ventral setae and mid-dorsal and dorsodistal simple setae. Propodus about as long as carpus, 1.7 times L:W, with one outer and three inner simple setae near dactylus insertion; fixed finger with two ventral setae, cutting edge with three setae and pointed claw; dactylus with three ventral setae and dorsal seta.
Pereopod-1 (Fig. 11B View Figure 11 ). Coxa with long seta (shorter than half of basis) and with oostegite. Basis narrow, about 3.9 times L:W, with mid-dorsal simple seta. Ischium with ventral simple seta. Merus with ventrodistal simple seta. Carpus with ventrodistal and dorsodistal simple setae. Propodus with one mid-ventral and three dorsodistal simple setae (two reaching dactylus distal margin). Dactylus naked. Unguis about 1.5 times as long as dactylus.
Pereopod-2 (Fig. 11C View Figure 11 ). Coxa with long seta (longer than half of basis) and with developed oostegite. Basis 2.8 times L:W, with mid-dorsal penicillate seta. Ischium with ventral simple seta. Merus slightly longer than wide, with ventrodistal simple seta. Carpus slightly longer than wide, with ventrodistal, distal and dorsodistal simple setae. Propodus with two ventrodistal and dorsodistal simple setae, and microtrichia. Dactylus naked. Unguis with tip broken.
Pereopod-3 (Fig. 11D View Figure 11 ) similar to pereopod-2. Merus as long as wide. Carpus 1.2 times L:W, with ventrodistal and dorsodistal simple setae. Unguis bent by the cover slip.
Pereopod-4 (Fig. 12A View Figure 12 ). Coxa with developed oostegite. Basis, 2.7 times L:W, naked. Ischium with two ventral simple setae. Merus with two ventrodistal spines. Carpus with three distal spines and dorsodistal simple seta. Propodus with ventrodistal spine and simple seta, three dorsodistal strong setae (two broken, one remained), and microtrichia. Dactylus almost completely fused with unguis (claw-like), about twice as long as unguis.
Pereopod-5 (Fig. 12B View Figure 12 ) similar to pereopod-4, except basis three times L:W, with two mid-dorsal and one mid-ventral penicillate setae. Propodus with two ventrodistal spines, mid-dorsal penicillate and three dorsodistal strong setae.
Pereopod-6 (Fig. 12C View Figure 12 ) Ventral view. Basis slender, 3.7 times L:W. Ischium with two ventral simple setae. Merus with two ventrodistal spines. Carpus with three distal spines and dorsodistal simple seta. Propodus with two mid-ventral spines and ventrodistal simple seta and three dorsodistal strong setae. Dactylus almost completely fused with unguis (claw-like), about 1.5 times as long as unguis.
Pleopods (Fig. 12D View Figure 12 ). Only the first pair of pleopods remaining but reduced; coxa naked; basis 1.7 times L:W, with a long inner seta; endopod completely absent; exopod short, with two strong distal setae.
Uropod (Fig. 12E View Figure 12 ). Basal article naked. Endopod two-articled; article-1 with two penicillate distal setae; article-2 with simple subdistal and three simple and one penicillate setae distally. Exopod one-articled, stout, 1.6 times L:W, 0.4 times as long as endopod, with three terminal simple setae.
Etymology.
Named in honor of Dr. Luciano Fischer ( NUPEM/UFRJ) for his competent coordination of the Project Rocky Shores, together with his enthusiasm and passion for the marine world.
Type locality.
Eulittoral zone of rocky shores at Areias Negras Beach, Rio das Ostras, Rio de Janeiro, Brazil.
Distribution.
This species was found within a macroalgae bank of the eulittoral zone of rocky shores at Areias Negras Beach, Rio das Ostras, Rio de Janeiro, Brazil, Southwestern Atlantic (Fig. 13 View Figure 13 ).
Ecology.
A total of seven specimens were found in only two of 56 quadrats (3.6%) collected at the Areias Negras Beach. The species occurred solely in the lower stratum. In the quadrats where the species was found, the substrate was mainly covered by the brown algae Sargassum (70% of the surface) and articulated calcareous algae Rhodophyta (20-25% of the surface).
Remarks.
The genus Pseudozeuxo is currently monotypic and includes P. belizensis (WoRMS, 2020b). Pseudozeuxo fischeri sp. nov. presents all the diagnostic characters of the genus. It is distinguished from P. belizensis by (1) pereopods 1-3 coxa with long seta about as half as long as basis; (2) pereopods 2-3 carpus with only seta ventrodistally ( P. belizensis has seta and spine); (3) pereopods 4-6 propodus with two spines and one seta ventrally; (4) uropod endopod article-2 0.8 times as long as article-1 ( P. belizensis with article-2 small, about 0.4 times as long as article-1) and exopod one-articled ( P. belizensis is two-articled).
Charbeitanais and Haimormus are recorded from the Pacific Ocean (Hong Kong and Japan, respectively; Bamber and Bird 1997; Kakui and Fujita 2018) and Pseudozeuxo is restricted to the Atlantic Ocean, being now recorded from the Southwestern Atlantic, besides the Caribbean Sea (Belize; Sieg 1982). Pseudozeuxo belizensis is a shallow water species (0.5-3 m depth) occurring at upper stratum of middle intertidal zone on coral reef ( Sieg 1982), a generally similar habitat to that of Pseudozeuxo fischeri .
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