Leodamas treadwelli Eisig, 1914

Dean, Harlan K. & Blake, James A., 2015, The Orbiniidae (Annelida: Polychaeta) of Pacific Costa Rica, Zootaxa 3956 (2), pp. 183-198 : 191-194

Leodamas treadwelli Eisig, 1914

Figures 5 (A–B), 6 (C)

Aricia cirrata Treadwell, 1901: 201 , Figs. 54–57. Homonym, Not Ehlers, 1897

Scoloplos treadwelli Eisig, 1914 (new name for A. cirrata Treadwell ).— Augener, 1927: 69.— Hartman, 1957: 283.— Maciolek & Holland, 1978: 164.— Vargas et al. 1985: 336.— Maurer et al. 1988: 47.— Dean, 1996a: 74.—de León- González & Rodriguez, 1996: 173.

Scoloplos armiger: Dean, 1996: 74 ; 2009: 146. Not Müller, 1776.

Material examined. Gulf of Nicoya: Sta. 15, 9°57′40″N, 84°47′'00″W, 15 m, sandy mud, 12 Jul 1980 (1). STA. 24, 9°49′25″N, 84°41′20″W, 11 m, sand, 1 Oct 1980 (1); Sta. 28, 9°52′16″N, 84°45′30"W, 26 m, mud, 10 Jul 1980, 1 ( MZUCR), 1 Oct 1980 (1), 7 June 1981, 1 ( MZUCR); Sta. 29, 9°54′55″N, 84°45′15″W, 18 m, muddy sand, 29 Jan 1981 (1); 4 Apr 1982, 1 ( MZUCR); Sta. 30, 9°54′40″N, 84°45′50″W, 18 m, muddy sand, 1 Oct 1980 (1). Punta Morales, Playa Blanca, lower intertidal, 10°3′47.2″ N, 84°57′9.2″ W, muddy sand, 20 Dec 1986, 3 ( MZUCR).

Description. All specimens incomplete, maximum thoracic width 0.66–1.75 mm ( Fig. 5 A). Prostomium small, triangular, pointed; lacking eyespots; nuchal organs not apparent. Peristomium subequal to prostomium, approximately 1.25 times as long and equal in width to setiger 1. Thorax wide, dorso-ventrally flattened; 14–20 setigers long, transition to abdomen abrupt. Branchiae from first abdominal setiger in all specimens, small at first, more erect, longer than parapodial lobes, in posterior segments.

Thoracic notopodia with short digitate postsetal lobe, approaching setal length in posterior thoracic setigers; thoracic neuropodia low ridges. Abdominal notopodial lobe erect, postsetal lobe large, triangular, longer than branchiae in anterior setigers, shorter in subsequent setigers; neuropodial parapodial lobe erect, truncate; presetal lobe a weak ridge ( Fig. 6 C).

Thoracic notosetae camerated capillaries; thoracic neurosetae short, acicular, in two rows anteriorly, single row in posterior thoracic setigers ( Fig. 5 A); thoracic acicula accompanied by a few dorsal capillaries in posterior thoracic setigers. Abdominal notosetae camerated capillaries accompanied by a single furcate setae with unequal smooth tines with blunt tips; delicate thin teeth on inner faces of each tine ( Fig. 5 B); abdominal neurosetae all camerated capillaries.

Remarks. Aricia cirrata Treadwell, 1901 , originally described from Puerto Rico, is a homonym of A. cirrata Ehlers, 1897 and was renamed Scoloplos treadwelli by Eisig, 1914. This species has now been more widely reported from the Caribbean, and the Pacific coast of Mexico; the species was redescribed by Hartman (1957) and Maciolek & Holland (1978). López, et al. (2003) described L. platythoracicus López, Claders , & San Martín, 2003, from Pacific Panama which is similar to L. treadwelli in the thoracic length and setal morphology but differs in the nature of the abdominal neuropodia. The anterior abdominal neuropodia is erect and blunt-ended in both species but those of L. platythoracicus have a notch on the lateral edge and a single, slightly protruding, aciculum. L. treadwelli lacks a notch in the anterior neuropodial lobe and the slightly projecting aciculum is accompanied by 2‒3 deeply embedded aciculae. L. texana ( Maciolek & Holland, 1978) from the Gulf of Mexico is also similar to L. treadwelli but has only single rows of acicular spines in the thoracic neuropodia whereas L. treadwelli has several double rows of spines on anterior thoracic neuropodia and single rows in posterior thoracic segments. L. minutis López, Cladera & San Martin, 2003 , also described from Pacific Panama, is morphologically similar to L. treadwelli but is unusual in that the first three thoracic setigers are uniramous with notopodia and notosetae entirely absent.

Distribution. Leodamas treadwelli was described by Treadwell (1901) as Aricia cirrata Treadwell, 1901 , from Puerto Rico and has been subsequently been reported from Colombia, Cuba, Curaçao, and Jamaica in the Caribbean (Dean, 2012). Hartman (1957) reported this species from Acapulco on the Pacific coast of Mexico and Maciolek & Holland (1978) later verified this identification. De León-González & Rodriguez (1996) reported the species from Baja California, Mexico. The present records extend the distribution south to Costa Rica in the Central American eastern Pacific. Collected in muddy to sandy sediments from 11‒ 26 m. in the Gulf of Nicoya.

Figures

FIGURE 5. Leodamas treadwelli: A, Station 28 Oct, Gulf of Nicoya specimen, anterior and midbody, lateral view; B, Station 28 Jun, Gulf of Nicoya specimen, notopodial furcate seta. Naineris setosa: C, Playa Blanca specimen, anterior end, dorsal view; D, Playa Blanca specimen, thoracic parapodia, posterior view; E, Playa Blanca specimen, anterior abdominal parapodia, posterior view; F, Playa Blanca specimen, posterior abdominal parapodia, posterior view; G, Playa Blanca specimen, notopodial furcate seta. Scoloplos cryptospinigerus n. sp.: H, Holotype, anterior end, dorsal view; I, Holotype, posterior thoracic neuropodial spines. Scale bars: A, D ‒ E, H = 500 µm, B, G, I = 10 µm, C, F = 1000 µm. s = neuropodial spines.

FIGURE 6. Leitoscoloplos pugettensis: A, Station 9, Bahia Culebra specimen, thoracic setiger, anterior view; B, Station 9, Bahia Culebra specimen, posterior notopodial flail setae. Leodamas treadwelli: C, Station 28 Jun, Gulf of Nicoya specimen, posterior abdominal setiger, anterior view; Scoloplos cryptospinigerus n. sp.: D, Holotype, anterior end, dorsal view; E, Holotype, thoracic parapodia, posterior view; F, Paratype, abdominal parapodia, anterior view; G, Paraytpe, thoracic neurosetal spines. Scale bars: A, F = 50 µm, B = 10 µm, C, E = 100 µm, D = 500 µm, G = 20 µm.