Sarsameira parexilis, Gee, 2009
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publication ID |
https://doi.org/ 10.1080/00222930903373991 |
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persistent identifier |
https://treatment.plazi.org/id/FC5A87B8-FF8A-7D2C-FE20-B18D9207F5BC |
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treatment provided by |
Felipe |
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scientific name |
Sarsameira parexilis |
| status |
sp. nov. |
Sarsameira parexilis sp. nov.
( Figures 6–10 View Figure 6 View Figure 7 View Figure 8 View Figure 9 View Figure 10 )
Material examined
Holotype
Adult ♀ dissected onto three slides. NHM Reg. no. 2009.160. Paratypes. Fifty-six ♀♀ (1 dissected onto 3 slides, 1 dissected onto 1 slide, 54 spirit preserved) and 30 ƋƋ (2 each dissected onto 3 slides, 1 dissected onto 1 slide, 27 spirit preserved), NHM Reg. nos 2009.161–165; 2009.166–175.
Description of female
Body. See Figure 6A–C View Figure 6 . Length 0.582–0.81 mm (mean 0.703 mm, n = 10), semicylindrical, widest at posterior margin of cephalothorax, tapering gradually posteriorly and without clear distinction between prosome and urosome. Cephalothorax tapering slightly anteriorly, ornamented with a few pores and sensilla. All prosomites with sensilla on posterior margin and plain hyaline frills. Urosomites -2 and -3 (genital double somite) completely fused, line of fusion marked only by a short dorso-lateral sub-cuticular rib ( Figure 6A–B View Figure 6 ), posterior part of double somite with a short ventro-lateral row of very small spinules on each side ( Figure 6C View Figure 6 ). Genital apparatus ( Figure 7A View Figure 7 ) with small copulatory pore only just posterior to genital slit, with reduced P6s forming small plates covering genital apertures, each armed with one large plumose seta. Urosomite-4 with two ventro-lateral rows of fine spinules on posterior border. Anal somite with plain semi-circular operculum dorsally and ventral surface with row of minute spinules near anterior border and a few very small spinules on posterior border at base of each caudal ramus. Latter about as long as broad, tapering slightly posteriorly, bearing seven setae, lateral seta I easily discernible but smaller than plain lateral seta-II, setae -III to -VI on terminal margin, setae -III and -VI slender and setae -IV and -V robust and long, triarticulate seta-VII arising near dorsal inner margin.
Rostrum. See Figure 6D View Figure 6 . Fused to cephalosome, small, not reaching middle of proximal segment of antennule, triangular with rounded anterior margin and a pair of lateral sensilla.
Antennule. See Figure 6E View Figure 6 . Slender, nine-segmented, segment-1 with small row of spinules, segment-2 longest, segments -7 and -8 very small, all setae naked, aesthetascs on segments -4 and -9. Setal formula as follows: 1-(1), 2-(10), 3-(8), 4-(3+(1+a)), 5-(2), 6-(2), 7-(2), 8-(2), 9-(5+(2+a)).
Antenna. See Figure 6F View Figure 6 . Basis with two-segmented exopod and endopod. Basis with a few spinules on abexopodal margin but without setae. Exopod proximal segment elongate with one minutely pinnate seta, distal segment small with one lateral and one terminal minutely pinnate seta. Proximal segment of endopod unarmed. Endopod distal segment ornamented with two rows of spinules on anterior face and a few spinules on outer margin; armature consists of two spines and one seta on outer margin and, on distal margin, five geniculate setae and one seta pinnate and swollen at base and fused to base of inner geniculate seta.
Mandible. See Figure 7B View Figure 7 . Coxal gnathobase well developed, relatively slender, cutting edge with large bicuspid tooth at outer corner, a large rounded unicuspid tooth medially, an array of small multicuspid teeth and a plumose seta at inner distal corner. Basis club-shaped, with row of setules on outer margin and spinules on inner margin; distal margin armed with two spines (one strongly dentate) and a plumose
seta. Endopod well developed with one lateral plumose seta and five setae (three fused at base) on distal margin. Exopod absent.
Maxillule. See Figure 7C and F View Figure 7 . Praecoxal arthrite with a row of spinules proximally and two small setae distally on inner margin; dorsal surface with two setae; distal margin with three pairs of curved spines. Coxal endite with two naked and one distally ringed and spinulose setae. Basis with one naked seta proximally and on distal margin, two or three naked setae and one weakly-developed but highly plumose seta. Endopod minute, fused to basis, with one naked seta; exopod with two or three naked(?) setae.
Maxilla. See Figure 7D View Figure 7 . Syncoxa with rows of spinules near proximal margin and two endites on distal margin; inner endite broad with one weakly-chitinized, fused seta with spinulose crown and one articulating pinnate seta; outer endite slender with two naked setae and a pectinate spine. Allobasal endite with a fused pectinate claw and an articulating pectinate spine. Endopod with two naked setae.
Maxilliped. See Figure 7E View Figure 7 . Syncoxa with rows of spinules proximally and two plumose setae on distal margin. Basis oval, unarmed but ornamented with row of spinules on palmar margin and medially and distally on outer margin. Endopod represented by a well-developed claw slightly longer than basis, with two accessory setae proximally.
P1. See Figure 8A View Figure 8 . Intercoxal sclerite small, U-shaped and unadorned. Praecoxa small, triangular with row of spinules on anterior margin. Coxa almost square, with four rows of spinules on anterior face and a row of setules near outer margin on posterior face. Basis with small row of spinules on distal margin and at base of inner and outer spine. Exopod three-segmented, segments about equal in length with row of spinules on outer margin; exp-2 with seta and row of setules on inner margin; exp-3 with two geniculate setae on distal margin and three spines on outer margin. Endopod three-segmented, enp-1 elongate, reaching distal margin of exp-3, inner margin with row of setules and a short stout plumose seta inserted at 76% of segment length; enp-2 only half length of enp-3, with row of spinules on outer margin and one plumose seta on inner margin; enp-3 about half length of enp-1 with one naked seta, one geniculate seta and one spine on distal margin.
P2–P4. See Figures 8B View Figure 8 and 9A View Figure 9 . Intercoxal sclerites bilobate and unadorned. Praecoxa and coxa as in P1. Basis with row of long setules in P2 and short spinules in P3–P4 on inner distal margin and spinules on distal margin and at base of outer spine on P2 and outer seta on P3–P4. All rami three-segmented and all segments with row of spinules on outer margin. P2 and P3 exp-1 with spinule row on posterior face; exp-2 with attenuated outer distal corner; enp-1 with short inner seta and enp-3 reaching to proximal part of exp-3. P4 exopod segments more elongate than in P2 and P3; exp-2 without attenuated distal outer corner; exp-3 with three inner setae, middle one very well developed and spinulose, distal inner seta extremely fine, articulating on posterior face of segment; enp-1 with long inner seta and enp-3 only reaching to distal margin of exp-2. Setal formula of swimming legs is presented in Table 2.
P5. See Figure 9B View Figure 9 . Baseoendopods of each side not fused medially and exopods also separate. Baseoendopod with well-developed endopodal lobe, reaching to middle of exopod; with outer peduncle bearing a slender seta and with five finely spinulose setae on distal margin. Exopod oval, not quite twice as long as wide; with a tube pore on proximal outer margin and six well-developed setae, inner terminal seta and second outer seta finely spinulose.
Description of male
As in female except for urosome, antennule, P1 basis, P5 and P6.
Body. See Figure 10A View Figure 10 . Length 0.462 –0.630 mm (mean = 0.544 mm, n = 10), urosomites -2 and -3 not fused. Urosomites -3 and -4 with long, and urosomite-5 with short, median ventral row of spinules on posterior margin, anal somite as in female.
Antennule. See Figure 10B–C View Figure 10 . Twelve-segmented, haplocer with slightly swollen segments -6 to -9 and major articulation between segments -9 and -10. Segment-1 with row of spinules, segment-2 a short segment bearing one seta. All setae naked except a specialized seta on segments -7 to -9, aesthetasc on segments -6 and -12. Setal formula tentatively given as follows: 1-(1), 2-(1), 3-(10), 4-(7), 5-(2), 6-(5 + (1+a)), 7-(2), 8-(2), 9-(3+1 spine), 10-(1+3 spines), 11-(4), 12-(5 + (2 + a)).
P1 basis. See Figure 8C View Figure 8 . Inner spine modified, stouter than in female and with a clawlike terminal structure with a hyaline centre.
P5. See Figure 10D View Figure 10 . Baseoendopods of each side fused medially, endopodal lobe not as developed as in female, bearing a surface pore and armed with four minutely pinnate spines, shorter and more robust that in female. Exopod oval, about one-third longer than wide with a tube pore and a few spines on outer margin and bearing five setae, three on outer margin slender and naked, terminal and inner seta minutely pinnate, latter less than a quarter the length of former seta.
P6. See Figure 10A View Figure 10 . Asymmetrical plates articulating with urosomite-2, each bearing three setae.
Etymology
From the Latin par meaning similar, so denoting the similarity of this species to Sarsameira exilis
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