Delavalia asetosa, Gómez, 2021
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publication ID |
https://doi.org/ 10.11646/zootaxa.5051.1.12 |
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publication LSID |
lsid:zoobank.org:pub:A99E653A-EBDF-48B1-BF24-0194136E03F9 |
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DOI |
https://doi.org/10.5281/zenodo.5563561 |
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persistent identifier |
https://treatment.plazi.org/id/227700CF-AAD7-4B7E-922A-8FFF161553F1 |
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taxon LSID |
lsid:zoobank.org:act:227700CF-AAD7-4B7E-922A-8FFF161553F1 |
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treatment provided by |
Plazi |
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scientific name |
Delavalia asetosa |
| status |
sp. nov. |
Delavalia asetosa sp. nov.
( Figs. 14–18 View FIGURE 14 View FIGURE 15 View FIGURE 16 View FIGURE 17 View FIGURE 18 )
urn:lsid:zoobank.org:act:227700CF-AAD7-4B7E-922A-8FFF161553F1
Type locality. Off central Sinaloa State, east of Pescadero Trough , southern Gulf of California, Mexico; Talud IV cruise, sampling station 19 (24.26667°N, 108.4019°W); depth 1,240 m; depth, 1240 m; organic carbon content, 3.96%; sand, 1.77%; clay, 49.12%; silt, 49.12 GoogleMaps %.
Specimens examined. Adult female holotype dissected and mounted onto seven slides (EMUCOP-250800- 01); August 25, 2000; coll. S. Gómez.
Etymology. The specific epithet from the ancient Greek ἀ-, a-, without, and the Latin seta, hair, makes reference to the lack of inner armature on P3–P4 EXP1. It is in the nominative singular. Gender feminine.
Description of female. Total body length measured from tip of rostrum to posterior margin of caudal rami, 592 µm; habitus (not shown) pyriform, widest at posterior end of cephalothorax, tapering posteriad; cephalothorax/body length ratio, 0.34.
Prosome and pedigerous somites largely as in previous species.
Urosome ( Figs. 14A, B View FIGURE 14 ) consisting of fifth pedigerous somite (first urosomite), genital double-somite (genital— second urosomite—and third urosomites fused), two free urosomites, and anal somite.Urosomites without expansions laterally nor dorsally; integument weakly sclerotized.
Fifth pedigerous somite (not shown) narrower than preceding somites; without spinular ornamentation.
Second and third urosomites completely fused dorsally and ventrally forming genital double-somite ( Fig. 14B View FIGURE 14 ), with dorsolateral trace of division ( Fig. 14A View FIGURE 14 ); genital double-somite as long as wide, widest part measured in proximal fourth close to P6; proximal half of genital double-somite with sensilla and few spinules dorsally ( Fig. 14A View FIGURE 14 ), ventrally without spinular ornamentation ( Fig. 14B View FIGURE 14 ); distal half of genital double-somite with posterior sensilla and dorsolateral spinular rows ( Fig. 14A View FIGURE 14 ), ventrally ( Fig. 14B View FIGURE 14 ) with few sensilla and without spinules; posterior hyaline fringe broad and smooth; genital complex hardly distinguishable, copulatory pores not exposed, paired genital apertures located ventrolaterally and covered by P6 ( Fig. 14B View FIGURE 14 ).
Fourth urosomite ( Fig. 14A View FIGURE 14 ) as distal half of genital double-somite, but with fewer spinules, with two ventral pores ( Fig. 14B View FIGURE 14 ).
Fifth urosomite without sensilla, with few lateral spinules ( Fig. 14A View FIGURE 14 ); ventrally with two medial sets of spinules as shown, with two ventral pores ( Fig. 14B View FIGURE 14 ).
Anal somite 2.5 times as wide as long ( Fig. 14A View FIGURE 14 ); with few spinules dorsally, laterally and ventrally with spinules around joint of caudal rami ( Figs. 14A, B View FIGURE 14 ), with spinules along medial cleft ventrally ( Fig. 14B View FIGURE 14 ); with one ventral pore on each side ( Fig. 14B View FIGURE 14 ); anal operculum without spinular ornamentation, semicircular, flanked by one sensilla on each side ( Fig. 14A View FIGURE 14 ).
Caudal rami elongate, about 6.2 times as long as wide ( Figs. 14A, B View FIGURE 14 ) and as long as three last urosomites combined; with small outer spinules at base of setae I and II, III, V and VII ( Figs. 14A–C View FIGURE 14 ); no pores detected; with seven setae ( Figs. 14A–C View FIGURE 14 ); setae I and II lateral, issuing at distal fifth, the former very small and ventral to seta II; seta III subdistal, issuing ventrally; setae IV and V distal, rat-tail like in distal half, with fracture plane; seta VI small, issuing at inner distal corner; dorsal seta VII triarticulate at base, plumose, situated subdistally close to inner margin.
Rostrum ( Fig. 15A View FIGURE 15 ) trapezoidal, not fused to cephalothorax, bifid, with two subdistal sensilla, without dorsal pore.
Antennule ( Fig. 15B View FIGURE 15 ) eight-segmented; all segments smooth, except for first segment with proximal spinular row; first segment without pore. All setae smooth, except for two and one slightly plumose seta on seventh and last segment, respectively; no setae with fracture plane detected; seventh segment with two, eighth segment with three articulated setae. Armature formula: 1(1); 2(11); 3(9); 4(5+(1+ae)), 5(3); 6(4); 7(4); 8(4+acro). Acrothek consisting of two setae and one minute aesthetasc fused basally.
Antenna ( Fig. 15B View FIGURE 15 ). Coxa short, with some outer spinules. Allobasis as long as free endopodal segment; with spinules as shown; with one abexopodal seta arising slightly above middle of inner margin. Free endopodal segment elongate; proximal half with longitudinal row of inner spinules, with subdistal outer strong spinules, with two outer subdistal frills; armature composed of two lateral spines and two setae, distally with one inner apical element, three apical geniculate setae and one slender element, and one outer distal pinnate element fused basally to slender seta. Exopod three-segmented; first and third segments longest; first and third segments with, second segment without subdistal spinules; first and second segments with one distal seta each, third segment with one proximal and three apical setae two of which seemingly fused basally.
Mandible ( Fig. 16A View FIGURE 16 ). Coxa relatively short, with one medial and one proximal spinular row. Gnathobase wide; ventral distal corner produced into small sharp semi-hyaline process; with two strong and several smaller teeth, two spines and two setae one of which pinnate. Basis elongate, with small spinules proximally, medially and subdistally, with three subdistal outer setae. Exopod arising from short pedestal, one-segmented, elongate, about 3.5 times as long as wide, and 0.4 times as long as basis, with three lateral and three apical setae, none of which fused basally. Endopod recurved, twisted over exopod, with three lateral setae, and five distal elements (three slender setae, one of which spinulose and one strong element, and longest element fused to endopod basally and with hyaline flange in middle part).
Maxillule ( Fig. 16B View FIGURE 16 ). Arthrite of praecoxa with two surface setae and some dorsal spinules proximally; distal armature composed of nine elements, of which one setiform and one strongly spinulose element, and one lateral spinulose recurved seta. Coxal endite with three setae; no spinules detected. Basis with two endites; proximal endite with four, distal endite with three slender setae. Exopod and endopod fused basally, separated from basis, onesegmented; endopod larger than exopod, with four setae; exopod small, with two setae.
Maxilla ( Fig. 16C View FIGURE 16 ). Large syncoxa with outer spinules as shown; with three endites; proximal endite bilobed, each lobe with two spinulose setae; middle and distal endites elongate, the latter slightly longer, with three spinulose setae each. Basis drawn out into strong claw, with strong spinulose spine and two slender setae, one of which arising from elongate setophore. Endopod one-segmented, with six slender setae (one arising basally, two medially, and three apically).
Maxilliped ( Fig. 16D View FIGURE 16 ) subchelate. Syncoxa rectangular, about two times as long as wide, with spinules as shown, with one bare and two spinulose strong elements, of which bare seta and one spinulose element set close to each other, the other spinulose seta arising distally from pedestal. Basis visibly shorter than syncoxa, oval, with outer spinules as shown, with one anterior and one posterior inner spinular row as depicted, with two slender distal setae. Endopod one-segmented, with one claw-like element and one seta.
P1 ( Fig. 17A View FIGURE 17 ). Intercoxal sclerite (not shown) transversely elongate, nearly straight, without surface ornamentation. Coxa massive, 0.8 times as wide as long, with two outer medial, one subdistal, and one medial row of spinules. Basis with spinules at the base of outer and inner spines, and at base of endopod. Exopod three-segmented, longer than endopod; no pores detected on exopodal segments; EXP1 longest, EXP3 shortest; all segments without outer nor inner acute distal processes; EXP1 and EXP2 with longitudinal row of outer spinules and inner slender setules, outer spines elongate, without inner armature; EXP3 with few outer spinules, with two outer elongate spines (distalmost spine displaced apically) and two apical small plumose setae (innermost apical seta displaced inwards). Endopod two-segmented, reaching middle of EXP2, segments without inner nor outer acute distal processes, no pores detected on endopodal segments; ENP1 barely reaching tip of EXP1, 1.2 times as long as wide, slightly longer than ENP2, with outer and distal spinules as shown, with one inner seta; ENP2 rectangular, about 1.6 times as long as wide, and 0.8 times as long as ENP1, with few outer spinules, with three distal elements, of which outermost a long element, medial a long strongly plumose seta, innermost a slender seta.
P2 (not shown) badly damaged. Intercoxal sclerite (not shown) not transversely elongate, trapezoidal, with strong pointed process on distal outer corners, without surface ornamentation. Coxa and basis as in P3. Exopod badly damaged, lost. Endopod three-segmented; no pores detected on endopodal segments; ENP1 and ENP2 with inner distal spinules; ENP1 shortest, ENP3 longest; ENP1 and ENP2 with outer acute and inner small distal process, outer process of ENP2 visibly longer; ENP1 with one, ENP2 with two inner elements; ENP3 with one apical outer spine, two apical elements, and one inner seta.
P3–P4 ( Figs. 17B View FIGURE 17 , 18A View FIGURE 18 ). Intercoxal sclerite (not shown) not transversely elongate, trapezoidal, with strong pointed process on distal outer corners, without surface ornamentation. Coxa with spinules as depicted. Basis of P3 with, of P4 without minute spinules at base of endopod and at base of outer basal seta, with acute process between rami and at inner distal corner, the latter larger. Exopod three-segmented, of P3 reaching middle of ENP3, of P4 visibly longer than ENP; no pores detected on exopodal segments; EXP1 and EXP2 with outer acute distal process (of P4 less developed), with longitudinal row of outer spinules and with inner distal frill, EXP3 with distal processes as shown; EXP1 without, EXP2 with inner armature; EXP3 with few outer spinules proximally, with three outer spines and two apical setae, of P3 with two, of P4 with three inner setae. Endopod three-segmented, of P3 visibly longer than, of P4 reaching middle of EXP3; pore present on P3 ENP3; spinular ornamentation of endopodal segments as shown; ENP1 shortest, ENP3 longest; ENP1 and ENP2 with outer acute and inner small distal process, outer process of ENP2 visibly longer, ENP3 with distal processes as shown; ENP1 with inner element, of P3 a slender plumose seta, of P4 a long stiff element with inner margin pinnate; P3 ENP2 with one slender inner seta, P4 ENP2 with long stiff inner element; P3 ENP3 with one apical outer spine, two apical elements, and three inner setae, of which proximal slender, medial and distal setae visibly thicker; P4 ENP3 with one apical outer spine, two apical elements, and two inner setae.
Setal formula of swimming legs as follows:
P5 ( Fig. 18C View FIGURE 18 ). Baseoendopod pentagonal; endopodal lobe poorly-developed, with four setae, of which outermost shortest and set closely to adjacent seta. Exopod oval, with outer spinules and five setae, of which medial shortest.
P6 ( Fig. 14B View FIGURE 14 ) represented by a minute flap covering ventrolateral genital aperture, fused to somite, without surface ornamentation, with one slender seta.
Male. Unknown.
Variability. No variability was detected in the single female found in the sediment samples.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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