Diarthopodella prima, 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.5563565 |
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persistent identifier |
https://treatment.plazi.org/id/D218962A-7F0A-FFCC-C099-FF18FB1A51C9 |
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treatment provided by |
Plazi |
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scientific name |
Diarthopodella prima |
| status |
sp. nov. |
Diarthopodella prima sp. nov.
( Figs. 31–35 View FIGURE 31 View FIGURE 32 View FIGURE 33 View FIGURE 34 View FIGURE 35 )
urn:lsid:zoobank.org:act:5B42B0DD-57F1-4B3F-96B2-5B93800F4FB1
Type locality. Guaymas Basin, between San Pedro Nolasco Island and Tortuga Island, Gulf of California, Mexico; Talud X cruise, sampling station 15 (27.7°N, 111.6333°W); depth 1,570 m; organic carbon content, 4.48%; organic matter content, 8.37%; sand, 4.49%; clay, 11.96%; silt, 84 GoogleMaps %.
Other locality. Off Sinaloa State, east of Pescadero Trough , Gulf of California, Mexico; Talud IV cruise, sampling station 19 (24.26667°N, 108.4019°W); depth, 1,240 m; organic carbon content, 3.96%; sand, 1.77%; clay, 49.12%; silt, 49.12 GoogleMaps %.
Specimens examined. From the type locality. Adult female holotype dissected and mounted onto ten slides (EMUCOP-110207-05); February 11, 2007; coll. S. Gómez.
From other localities. Copepodite CV paratype dissected and mounted onto six slides (EMUCOP-250800-02); August 25, 2000; coll. S. Gómez.
Etymology. The specific epithet from the Latin prima , first, makes reference to the first species attributed to the new genus. 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, 660 µm; habitus pyriform, widest at posterior end of cephalothorax, tapering posteriad ( Fig. 31A View FIGURE 31 ); cephalothorax/body length ratio, 0.3.
Prosome and pedigerous somites ( Fig. 31A View FIGURE 31 ) largely as in previous species.
Urosome ( Fig. 31A, D View FIGURE 31 ) consisting of fifth pedigerous somite (first urosomite), genital double-somite (genital— second urosomite—and third urosomite fused), two free urosomites, and anal somite. Urosomites without expansions laterally nor dorsally; integument weakly sclerotized.
Fifth pedigerous somite ( Fig. 31A View FIGURE 31 ) narrower than preceding somites, with some sensilla dorsally, without spinular ornamentation.
Second and third urosomites completely fused dorsally and ventrally forming genital double-somite ( Fig. 31D View FIGURE 31 ), with dorsolateral trace of division ( Fig. 31A View FIGURE 31 ); genital double-somite 1.2 times as long as wide, widest part measured in proximal third close to P6; proximal half with few dorsal sensilla and with two dorsolateral sets of spinules ( Fig. 31A View FIGURE 31 ), ventrally without sensilla nor spinules ( Fig. 31D View FIGURE 31 ); distal half with dorsolateral sensilla and spinular rows ( Fig. 31A View FIGURE 31 ), ventrally with few sensilla and without spinules ( Fig. 31D View FIGURE 31 ); posterior hyaline fringe broad and smooth; genital complex hardly distinguishable, copulatory pores not exposed, paired genital apertures located ventrolaterally and covered by P6 ( Fig. 31D View FIGURE 31 ).
Fourth urosomite ( Figs. 24A View FIGURE 24 , 25A–B View FIGURE 25 ) as distal half of genital double-somite; no pores detected.
Fifth urosomite as previous somite but without sensilla ( Fig. 31A, D View FIGURE 31 ); no pores detected.
Anal somite about twice as wide as long ( Fig. 31A View FIGURE 31 ), with spinules around joint of caudal rami ( Figs. 31A, D View FIGURE 31 ), medial cleft with ventral spinules as shown ( Fig. 31D View FIGURE 31 ), with one dorsolateral pore on each side ( Fig. 31A View FIGURE 31 ); anal operculum without spinular ornamentation, semicircular, flanked by one sensillum on each side ( Fig. 31A View FIGURE 31 ).
Caudal rami elongate, about 4.4 times as long as wide ( Fig. 31A, D View FIGURE 31 ) and slightly longer than fifth and anal somites combined, outer and inner margins nearly straight, with outer spinules at base of setae I and II, III, V, and VII ( Fig. 31A–E View FIGURE 31 ); with seven elements ( Fig. 31B, C, E View FIGURE 31 ); setae I and II situated more proximally than in the previous species, in distal third, lateral, seta I setiform and ventral to seta II, the latter long; seta III subdistal, arising at distal sixth, ventrolateral ( Fig. 31B, C,. E View FIGURE 31 ; detached during dissection in Fig. 31C–D View FIGURE 31 ); setae IV and seta 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, aligned with seta III, arising close to inner margin.
Rostrum ( Fig. 31A View FIGURE 31 ) trapezoidal, elongate, not fused to cephalothorax, bifid, with two subdistal sensilla, without dorsal pore.
Antennule ( Fig. 32A View FIGURE 32 ) eight-segmented, all segments smooth; first segment without pore. All setae smooth; only one seta with fracture plane detected on third segment; seventh segment with one, eighth segment with four articulated setae. Armature formula: 1(1); 2(10); 3(8); 4(6 + (1 + ae)), 5(3); 6(3); 7(4); 8(5 + acro). Acrothek consisting of two setae and one minute aesthetasc fused basally.
Antenna ( Fig. 32B View FIGURE 32 ). Coxa short, with some outer spinules. Allobasis as long as free endopodal segment, with spinules midway inner margin, with one abexopodal seta arising slightly above the middle of inner margin. Free endopodal segment elongate; proximal half with longitudinal row of strong inner spinules, distal half with subdistal outer strong spinules, with two outer subdistal frills; armature composed of two spines and two setae laterally, distally with one inner apical spine, 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 middle segments without, third segment with spinules as shown; 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. 33A View FIGURE 33 ). Coxa relatively short. Gnathobase wide; ventral distal corner produced into small sharp semi-hyaline process; with one strong and several smaller teeth, two spines and two setae, of which one pinnate. Basis elongate, spinular ornamentation as shown, 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; laterally with two proximal subequal setae and one subdistal comparatively longer element, distally with four distal elements, of which longest fused to endopod basally and with hyaline flange in middle part.
Maxillule ( Fig. 33B View FIGURE 33 ). Arthrite of praecoxa with two surface setae and few dorsal spinules; distal armature composed of seven elements as shown, one medial small seta, and one lateral pinnate recurved seta. Coxal endite with three setae and with apical spinules. Basis with two endites; proximal endite seemingly with three, distal endite seemingly with two slender setae. Exopod and endopod fused basally, separated from basis, one-segmented; endopod larger than exopod, with four setae; exopod with two setae.
Maxilla ( Fig. 33C–E View FIGURE 33 ). Large syncoxa with outer spinules as shown; with three endites; proximal endite bilobed, proximal lobe with one, distal lobe with two setae; middle and distal endites elongate, the latter slightly longer, with three spinulose setae each ( Fig. 33E View FIGURE 33 ). Basis drawn out into strong claw, with strong spine and two slender setae, one of which arising from elongate setophore ( Fig. 33D View FIGURE 33 ). Endopod one-segmented, with six slender setae (one arising basally, one medially, and four apically).
Maxilliped ( Fig. 33F View FIGURE 33 ) presumably subchelate, endopod lost during dissection. Syncoxa slightly longer than wide, visibly longer than basis; seemingly without spinular ornamentation; with one bare and two spinulose strong elements, of which bare seta and one spinulose element at the same level, the other arising distally from pedestal. Basis shorter than syncoxa; rectangular; with some outer spinules; with one anterior and one posterior inner spinular row as figured; with two slender distal setae.
P1 ( Fig. 34A View FIGURE 34 ). Intercoxal sclerite (not shown) transversely elongate, nearly straight, without surface ornamentation. Coxa massive, 1.4 times as wide as long, with outer and medial spinules as shown. Basis with spinules at base of outer and inner spines and between rami, with spinules midway inner margin. Exopod twosegmented, visibly shorter than endopod, reaching proximal third of ENP2; segments without outer nor inner acute distal processes; no pores detected on exopodal segments; EXP1 and EXP2 subequal in length; both segments with outer spinules as depicted; EXP1 without inner seta, EXP2 with five elements, of which outermost spine probably homologous to the outer spine of the second exopodal segment of other species of the subfamily, and two innermost setae short, setulose and rat-tail like in distal half. Endopod two-segmented, visibly longer than exopod; segments without outer nor inner acute distal processes; no pores detected on endopodal segments; ENP1 reaching proximal fourth of EXP2, 2.3 times as long as wide, and 0.7 times as long as ENP2, with few inner long spinules and with longitudinal outer and apical spinules as shown, with inner seta; ENP2 elongate, visibly longer than ENP1, six times as long as wide, inner proximal margin with few slender spinules, with longitudinal rows of outer spinules, with one inner seta issuing at proximal third, one inner apical slender seta, one medial apical pinnate element, and one outer apical spine.
P2 ( Fig. 34B View FIGURE 34 ). Intercoxal sclerite (not shown) not transversely elongate, trapezoidal, with strong pointed process on distal outer corners, without surface ornamentation. Coxa with outer spinules proximally and medial minute spinules subdistally. Basis with strong acute inner process, with much smaller process between rami, with inner long and selender spinules, with outer seta. Exopod three-segmented, reaching slightly below middle of ENP3; first and third segments longest; EXP1 and EXP2 with outer acute distal process, with outer and distal spinules, and with distal inner frill as shown, distal processes of EXP3 as shown; EXP1 without, EXP2 with subdistal outer pore; EXP1 and EXP2 with one inner seta; EXP3 seemingly without spinular ornamentation, with two inner setae, two apical elements and three outer spines. Endopod three-segmented, longer than exopod; ENP1 shortest, about 0.7 times as long as ENP2; ENP2 and ENP3 subequal in length; all endopodal segments with longitudinal row of outer spinules; ENP1 and ENP2 with outer and inner acute distal processes, but outer process of ENP2 remarkably longer, both segments with apical minute spinules, distal processes of ENP3 as shown; ENP3 with subdistal medial pore; ENP1 with one, ENP2 with two inner setae; ENP3 with one inner seta, two apical elements and one outer spine.
P3 ( Fig. 35A View FIGURE 35 ). Intercoxal sclerite (not shown) as in P2. Coxa as in P2 but with additional subdistal outer spinular row, seemingly without medial minute spinules subdistally. Basis as in P2 but with exceedingly long outer seta. Exopod three-segmented, shorter than endopod, reaching distal fourth of ENP; EXP1 and EXP2 as in P2, but will less developed outer distal processes and with ninner setules; EXP3 with distal processes as shown, with few outer proximal spinules, with subdistal pore, with three inner setae, of which distalmost thicker, two apical elements, and three outer spines. Endopod largely as in P2, except for inner seta of ENP1 long as stiff, and armature complement of ENP2 (with one instead of two inner setae) and ENP3 (with three instead of one inner seta).
P4 ( Fig. 35B View FIGURE 35 ). Intercoxal sclerite (not shown), coxa and basis largely as in P3, except for shorter outer seta of basis. Exopod visibly longer than endopod; EXP1 and EXP2 with outer acute distal process less developed than in P3, of EXP3 as shown; EXP1 and EXP2 without, EXP3 with subdistal pore; ornamentation and armature complement as in P3. Endopod three-segmented, shorter than exopod, reaching middle of EXP3; outer distal processes of endopodal segments largely as in P3 except for less developed outer process of P4 ENP2; spinular ornamentation as in P3; ENP3 with subdistal inner pore; ENP1 and ENP2 as in P3, but with longer inner elements; ENP3 with two inner, two apical and one outer spine.
Setal formula of swimming legs as follows:
P5 ( Fig. 32C View FIGURE 32 ). Baseoendopod pentagonal; endopodal lobe poorly-developed, with four setae, of which two outermost and adjacent two setae smooth and set close together, innermost seta separated by wide gap and pinnate. Exopod oval, with some outer spinules, with five setae, of which outer and distal outer setae pinnate, others smooth (innermost medial seta lost during dissection).
P6 ( Fig. 31D View FIGURE 31 ) 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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