Tapholeon inconspicuus Gheerardyn and Fiers, 2007
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publication ID |
https://doi.org/ 10.1080/00222930701695629 |
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persistent identifier |
https://treatment.plazi.org/id/D34587E1-FFA4-FFC8-FEF9-FC6A56E7FC57 |
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treatment provided by |
Felipe |
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scientific name |
Tapholeon inconspicuus Gheerardyn and Fiers |
| status |
sp. nov. |
Tapholeon inconspicuus Gheerardyn and Fiers sp. nov.
( Figures 7–9 View Figure 7 View Figure 8 View Figure 9 )
Type locality
Western Indian Ocean, Kenyan coast, Wasini Island (4 ° 409S, 39 ° 239E), red (terrigenous?) sediment, water depth 3– 4 m.
Material
From type locality: one female holotype dissected on four slides ( COP 4734 View Materials a–d); one male allotype dissected on three slides ( COP 4735 View Materials a–c); one male and one female paratype preserved in 70% alcohol ( COP 4736 View Materials ) ; collected 28 February 2002 by M. Raes.
Etymology
The specific name inconspicuus (Latin meaning inconspicuous) refers to the low occurrence of this species in a sample with a high number of Tapholeon tenuis sp. nov.
Description of female Total body length 389–415 Mm (n 52; average5402 Mm; measured from anterior margin of rostrum to posterior margin of caudal rami). Largest width measured at posterior margin of cephalothorax: 97 Mm.
Habitus ( Figure 7A, B View Figure 7 ) elongate, somewhat more robust; slightly dorso-ventrally depressed; with distinct convex curvature in lateral aspect. Genital double-somite and following urosomite slightly extended laterally. Integument of cephalothorax smooth; regularly ornamented with small sensilla. Pleurotergites of prosomites and urosomites and dorsal surface of anal somite clothed with irregular pattern of small denticles, some of which arranged in transversal rows. Posterodorsal margin of cephalothorax smooth, of all free somites strongly serrate. Posterodorsal margins of cephalothorax and free somites (except second urosomite) with long slender hairs, all bearing number of sensilla (not in penultimate urosomite). Anal operculum convex with slightly serrate margin, not protruding.
Ventral surface ( Figure 9A View Figure 9 ) of genital double-somite smooth in anterior half, bearing small spinules in posterior half. Copulatory pore minute, situated in middle of anterior somite. Ventral surface of following two urosomites with rows of small spinules. Genital double-somite and following two urosomites laterally with spinules. Anal somite ventrally smooth, laterally with few spinules. Ventral surface of caudal rami with few rows of small spinules. Posteroventral margins of genital double-somite and of following two urosomites bearing row of small spinules and clothed with long slender hairs. Posteroventral margin of anal somite with row of spinules; one pair of spinules very long (two-thirds length of caudal ramus) and flattened.
Caudal rami ( Figure 9C View Figure 9 ) flattened; 1.5 times as long as wide; not touching each other along inner margin. Dorsal surface covered with small denticles; inner margin with small spinules along proximal half. Distal half of inner margin strongly serrate. Seta I, II, and III inserted just beyond middle of outer margin, seta VII near middle of ramus. Seta IV and V not fused, both pinnate; all other setae naked. Seta I rudimentary.
Antennule ( Figure 9D View Figure 9 ) six-segmented; suture between fourth and fifth segment incomplete. Second segment bearing small blunt process along outer margin. Majority of setae long and slender; second segment with strong, armed spine near outer margin; certain setae on ultimate segment short and stout. Armature formula as in type species.
Antenna and mouthparts as in type species.
P1 ( Figure 8A View Figure 8 ): exopod one-segmented, bearing six setae. Enp-1 five times as long as exp.
P2–P4 ( Figure 8B–D View Figure 8 ) with three-segmented exopods and two-segmented endopods. Exp-1 and exp-2 equal in length; exp-3 slightly longer. Pattern of spinules as figured. Setal formula in Table I.
P5 ( Figure 8E View Figure 8 ) with separate exopod and baseoendopod. Margins and surface of rami with spinules. Baseoendopod reaching to middle of exopod; bearing one apical and three lateral setae. Exopod ovate; two times as long as wide; bearing five setae.
P6 vestige ( Figure 9A View Figure 9 ) bearing one seta.
Description of male Total body length 389–402 Mm (n 52; average5396 Mm; measured from anterior margin of rostrum to posterior margin of caudal rami). Largest width measured at posterior margin of cephalothorax: 84 Mm.
Habitus as in female; except for fully separated second and third urosomites and lack of lateral extensions in second to fourth urosomites ( Figure 9B View Figure 9 ). Ventral surface of third urosomite densely covered with several rows of spinules. Posteroventral margin of anal somite with row of small spinules, i.e. without pair of very long spinules as in female.
Antennule ( Figure 9E View Figure 9 ) seven-segmented; sub-chirocer. Shape of first and second segment as in female.
Antenna, mouthparts, and P1–P4 as in female.
P5 ( Figure 9F View Figure 9 ): endopodal lobe of P5 obsolete; without seta. Exopod small; slightly wider than long; bearing one naked and three plumose seta(e).
P6 vestiges ( Figure 9B View Figure 9 ) asymmetrical; each bearing one plumose inner and one naked outer seta.
Variability
The holotype has an aberrant right P3 exopod (0.1.222). The drawing of P3 was made from the female paratype.
Differential diagnosis
The present species exhibits an unusual type of sexual dimorphism, i.e. in the female the posteroventral margin of the anal somite bears a pair of very long (two-thirds length of caudal ramus) and flattened spinules. In the male, these modified spinules are absent. Furthermore, this species has a one-segmented exopod in P1 and bears three outer spines on the ultimate segments of the exopods of P2–P4.
Distribution
Wasini Island, Kenyan coast (present study).
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.