Leitoscoloplos multipapillatus Hernández-Alcántara & Solís-Weiss, 2014

Dean, Harlan K. & Blake, James A., 2015, The Orbiniidae (Annelida: Polychaeta) of Pacific Costa Rica, Zootaxa 3956 (2), pp. 183-198 : 184-186

Leitoscoloplos multipapillatus Hernández-Alcántara & Solís-Weiss, 2014

Figures 1 (A–C), 2 (A), 4 (A)

Leitoscoloplos multipapillatus Hernández-Alcántara & Solís-Weiss, 2014:143 ‒146.

Material examined. Gulf of Nicoya: Station (STA.) 24, 9°49ˊ25″N, 84°41ˊ20″W, 11 m, sand, 1 Oct 1980 (1). STA 29, 9°54ˊ55″N, 84°45ˊ15"W, 18 m, muddy sand, 1 Oct 1980 (1); 6 Jul 1980 (2); 4 Apr 1982 (1). STA. 30, 9°54ˊ40″N, 84°45ˊ50″W, 18 m, muddy sand, 27 Jan 1981 (1). Bahia Culebra: STA. 1, 10º35ˊ24.8″N, 85º39ˊ41.6"W, 1.5 m, 19 May 2011 (2).

Description. Complete specimen 21.9 mm long, 0.61 mm maximum thoracic width for 76 setigers ( Fig. 1 A, 2A); incomplete specimens maximum thoracic width 0.60–0.66 mm. Prostomium conical, longer than wide; eyespots absent; paired dorso-lateral nuchal organs present. Peristomium approximately one-half prostomial length, subequal to first setiger. Thorax with 15–19 setigers, widest in middle. Branchiae from setiger 9, short, triangular at first, becoming longer and more robust in posterior thoracic setigers each branchial pair located along dorsal mid-line. Thoracic parapodia weakly developed as low ridges; neuropodial postsetal lobes triangular, those of notopodia narrow; postsetal lobes increasing in length along thorax, subequal to setal length in posterior thoracic setigers; conical ventral cirrus present ( Figs. 1 A, 4A). Stomach papillae present in the posterior thoracic and anterior abdominal region, on setigers 14–19 of 17 thoracic setiger specimen, on setigers 17–22 of 18 and 19 thoracic setiger specimens respectively, and on setigers 14–18 on 15 thoracic setiger specimen; maximally 12 papillae per setiger ( Fig. 4 A). Abdominal notopodial postsetal lobes subequal to branchiae, wide with narrow distal region; neuropodial postsetal lobes bifid, lateral branch approximately one-half median branch length; welldeveloped subpodial flange ventral to neuropodial lobe ( Fig. 1 B). Interramal cirri usually present on first several abdominal setigers; larger specimen with interramal cirri on last two thoracic setigers and first five abdominal setigers, those on thoracic segments actually emerging from superior border of notopodial pre-setal lobe. Posterior end slightly widened with approximately 12 closely spaced, dorso–ventrally flattened segments, pygidium scoop– shaped ( Fig. 1 C).

Notosetae and neurosetae all camerated capillaries; thoracic neuropodia with row of longer capillaries and row of shorter capillaries in upper region of fascicle, lower region with double row of many short setae ( Fig. 1 A); abdominal notopodia with 6–8 long capillaries, neuropodia with 3–5 long capillaries; furcate setae absent ( Fig. 1 B).

Remarks. Based on the number of setigers in the thorax and first appearance of the branchiae, L. multipapillatus is most similar to L. panamensis (Monroe, 1933) , L. mammosus Mackie, 1987 and M. bifurcatus ( Hartman, 1957) . L. panamensis has a 17 setiger thorax and branchiae from setiger 9, but the thoracic neuropodial postsetal lobes are bifurcate in L. panamensis . Additionally, a single subpodial papilla occurs on three or four posterior thoracic segments with two on the last thoracic segment of L. panamensis while L. multipapillatus has numerous ventral papillae (stomach papillae) on both posterior thoracic and anterior abdominal segments. L.

bifurcatus has 20–21 thoracic setigers and branchiae from setigers 8‒9 but this species differs from L. multipapillatus in having bifurcate thoracic neuropodial lobes in posterior thoracic setigers and lacking stomach papillae. L. mammosus also has branchiae from setigers 9–11 but only has 14–15 thoracic setigers ( Mackie 1987). L. mammosus also lacks stomach papillae and has a long, digitate (rather than foliaceous) notopodial lobe in abdominal setigers.

A ventral fringe of stomach papillae on the last several thoracic and first several abdominal setigers has been reported in several genera of orbiniids including Phylo , and Orbinia ( Blake 1996) . In his review of the genus Leitoscoloplos Mackie (1987) reported that L. obovatus Mackie, 1987 was the only member of the genus with stomach papillae on the last several thoracic setigers with a single papilla located some distance from the neuropodial lobe. This single papilla, however, represents a subpodial lobe rather than stomach papillae which are numerous and extend as a band of papillae transversely across the ventrum ( Blake 1996). Eibye Jacobsen (2002) later described two species from the Andaman Sea in the Indian Ocean with a well-developed array of stomach papillae, L. mackiei Eibye Jacobsen, 2002 and L. papillatus Eibye Jacobsen, 2002 . Both differ from L.

multipapillatus in the length of the thorax and first occurrence of branchiae with L. mackiei having 17 thoracic setigers with branchiae beginning on setiger 13 and L. papillatus having a thorax of 14–15 setigers with branchiae beginning on setigers 9–11.

L. mackiei has up to six stomach papillae on posterior thoracic setigers while there are only one or two subpodial papillae on anterior abdominal setigers. L. papillatus has up to seven stomach papillae but they are found only on the abdomen. Both of these species differ from L. multipapillatus in that it has up to 12 stomach papillae per segment and a large number of stomach papillae occurring on both thoracic and abdominal setigers.

Distribution. This species was recently described by Hernández-Alcántara & Solís-Weiss (2014) from shallow subtidal waters in fine to muddy sands in the Gulf of California in eastern Pacific Mexico. It is known from the Gulf of Nicoya and Bahia Culebra on the Pacific coast of Costa Rica in sand and mud/sand sediments.

Figures

FIGURE 1. Leitoscoloplos multipapillatus: A, Posterior thoracic parapodium, posterior view; B, Station 29, Gulf of Nicoya specimen, thoracic setiger, anterior view; C, Station 1, Bahia Culebra specimen, posterior end and pygidium. Leitoscoloplos panamensis: D, Station 29, Gulf of Nicoya specimen, thoracic setiger, anterior view; E, Station 29, Gulf of Nicoya specimen, anterior abdominal setiger, anterior view; F, Station 28 Jun, Gulf of Nicoya specimen, posterior abdominal setiger, anterior view. Scale bars: A ‒ F = 100 µm. br = branchiae, ic = interramal cirri, neL = neuropodial lamellae, noL = notopodial lamellae, p = prostomium, per = peristomium, sp = subpodial papillae, vc = ventral cirri.

FIGURE 4. Leitoscoloplos multipapillatus: A, Setigers 17 – 19, ventral view. Leodamas hamatus n. sp.: B, Paratype XXX Anterior region, lateral view; C, Anterior thoracic spines, setiger three, mid-neuropodial region; D, Posterior thoracic spines, setiger 15, mid-neuropodial region; E, Posterior thoracic spines, upper neuropodial region; F, Furcate notosetae, posterior abdominal region; G, Posterior emergent neuroaciculum, posterior abdominal region. Scale bars: A = 200 µm, B = 500 µm, C ‒ E, F, G = 10 µm. h = hoods, stp = stomach papillae.