Leodamas hamatus
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Familia: Orbiniidae
Genus: Leodamas
Name
Leodamas hamatus Dean, Harlan K., 2015 – Wikispecies link – Pensoft Profile
- Leodamas hamatus Dean, Harlan K., 2015, Zootaxa 3956: 188-191.
Materials Examined
Material examined. Gulf of Nicoya: Punta Morales, South point, 10 ° 3 ′30.2″N, 84 ° 57 ′4.8″W, intertidal, muddy sand, Jul 1995, Holotype (MCZ50373); Sta. 2, 9 º 55 ′ 28 ″N, 84 º 52 ˊ05″ W, 18 m, muddy sand, 13 July 1980 (1); Sta. 24, 9 ° 49 ′ 25 ″N, 84 ° 41 ′ 20 "W, 11 m, sand, 10 Jul 1980 (1), 1 Oct 1980 (5), 27 Jan 1981, 2 Paratypes (MCZ83993) (1), 4 Apr 1982, 1 Paratype (MCZ50374); Sta. 28, 9 ° 52 ′ 16 ″N, 84 ° 45 ′ 30 ″W, 26 m, mud, 1 Apr 1982, 2 (MCZ83996); Sta. 29, 9 ° 54 ′ 55 ″N, 84 ° 45 ′ 15 ″W, 18 m, muddy sand, 1 Oct 1980, 1 Paratype (MZUCR30 - 3) (6), 27 Jan 1981, (2). Paratypes (MZUCR153 -01 & MZUCR31 -02) (6), 7 Jun 1981, 1 Paratype (MCZ50375) (2), 1 Apr 1982, 2 Paratypes (MCZ50377 (SEM) (2); Sta. 30, 9 ° 54 ′ 40 ″N, 84 ° 45 ′ 50 ″W, 18 m, muddy sand, 10 Jul 1980, 1 Paratype (MCZ83992); Sta. 31, 9 ° 44 ′00″N, 84 ° 59 ′ 42 ″W, 20 m, mud/sand, 9 Jul 1980 (1); Sta. 35, 9 ° 55 ′ 42 ″N, 84 ° 47 ′ 40 ″W, 13 m, sand, 12 Jul 1980 (1). Punta Morales: Playa Blanca, 10 °04′N, 84 ° 58 ′W, lower intertidal, muddy sand, 1986, 1Paratype (MZUCR156 -01), col: J. A. Vargas; South point, 10 ° 3 ′30.2″N, 84 ° 57 ′4.8″W, mid intertidal, muddy sand, 29 Aug 1988, col: H. K. Dean, (2); east of South Point, 10 ° 3 ′34.9″N, 84 ° 57 ′6.0″W, intertidal fine sand, col: H. K. Dean, 29 Aug 1988, 2 Paratypes (MCZ50378). Guanacaste, Bahia Culebra: Sta. 3, 10 º 35 ′42.9"N, 85 º 39 ′16.6″W, 13 m, 19 May 2011 (1); Sta. 12, 10 º 35 ′56.5″N, 85 º 40 ′34.6″W, 12 m, 19 May 2011 (1).
Description
Description. An elongate species, all specimens incomplete, maximum thoracic width 0.30–1.23 mm. Holotype incomplete, 32 mm long, 0.8 mm wide with 115 segments (Figs. 3 A, 4 B). Prostomium conical; eyespots absent; paired dorsolateral nuchal organs present. Peristomium slightly shorter than prostomium, subequal to first setiger. Thorax with 13–21 setigers, holotype with 18; transition to abdomen abrupt. Short, conical branchiae from setiger 6 in all specimens, increasing in length posteriorly. Thoracic notopodial presetal lobe a low ridge, postsetal lobe short, conical at first, increasing in length posteriorly; thoracic neuropodia with low presetal ridge, postsetal ridge somewhat higher (Fig. 2 F). Abdominal notopodial postsetal lobe conical, shorter than branchiae; abdominal neuropodia with presetal lobe a low ridge, postsetal lobe triangular; with a single well-developed, projecting acicula which enlarges with a hooked tip (Fig. 3 B, G) and becomes greatly emergent in far posterior setigers (Fig. 4 G).
Thoracic notosetae camerated capillaries throughout; neurosetae include a small dorsal fascicle of 2‒7 thin capillaries and rows of heavy uncini arranged in 2‒4 complete longitudinal rows, with a partial posteriormost fifth row; uncini with 5‒8 transverse rows of small serrations on shaft (Figs. 3 C–D, 4 –D). First four or five thoracic setigers with narrow uncini with a blunt tip, and thin, appressed hood (sometimes eroded) (Figs. 3 C, 4 C); subsequent thoracic uncini much more robust with thickened hood (Figs. 3 D, 4 D) that together with curved tip, providing uncini with a bifurcate appearance; 5‒8 serrated ridges on shaft (Figs. 3 E, 4 D). Uppermost few uncini short with wide rounded tip and a thick hood projecting slightly beyond the tip in all thoracic setigers (Fig. 4 E). Abdominal notosetae camerated capillaries accompanied by 1‒3 furcate setae posteriorly (Figs. 3 F, 4 F), each with slightly unequal length tines and coarse spines along the median borders.
Discussion
Remarks. Blake (2000) noted that Leodamas should be recognized as a genus separate from Scoloplos as its thoracic neuropodial spines are thicker than the narrow, pointed spines of Scoloplos and are not accompanied by numerous capillaries in the setal fascicle (see S. cryptosetosa n. sp. below) as occurs in Scoloplos. Blake (1996) considered the subgenus Scoloplos (Leodamas) to differ from Scoloplos (Scoloplos) in that the onset of branchiae occurred anterior to setiger 7 rather than posterior to setiger 8. Later, Blake (2000) treated Leodamas as a full genus and noted that while most species in this genus have the first branchiae on the anterior part of the thorax at about setiger 6, there is one group of species represented by L. treadwelli (see below) where the branchiae begin more posteriorly; the generic status of this group of species is currently being reviewed (Blake, in prep.).
Etymology
Etymology. Hamatus is Latin for hooked, referring to the large curved neuropodial spines found on this species.
Distribution
Distribution. Collected in muddy to sandy sediments from 11–26 m in the Gulf of Nicoya and from 12–13 m in Bahia Culebra, Costa Rica.
Taxon Treatment
- Dean, Harlan K.; Blake, James A.; 2015: The Orbiniidae (Annelida: Polychaeta) of Pacific Costa Rica, Zootaxa 3956: 188-191. doi
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