Polyodontes frons Hartman 1939

Polyodontes frons Hartman, 1939

Pansthalis oculea Treadwell, 1901:188 [part].

Polyodontes frons Hartman, 1939b:84, pl. 25: figs. 300–308; 1942:96.

Polyodontes lupina.—Day, 1973:9. [Not Polyodontes lupinus (Stimpson, 1856).]

MATERIAL EXAMINED.—PANAMA (Pacific). Piñas Bay, NNE of Pt. Isla, 37 m, mud, sta 443–35, 29 Jan 1935, holotype of P. frons (AHF 54).

GULF OF MEXICO. Off Sombrero Light, 128 m, gray sandy marl, A.R. Thompson and P.L. McGinty, collectors, 5 Jun 1950, 1 specimen (USNM 50702). 25°N, 84°W, 128m, M.L. Jones, collector, 14 Jul 1965, 1 specimen (USNM 50730). 27°52′N, 94°56′W, 121–181 m, Alaminos sta 65A10-13C, 28 Jun 1964, 1 specimen (USNM 71436).

SOUTH ATLANTIC. East coast of South America off Argentina, 36°43′S, 56°23′W, 19 m, sand, broken shells, Albatross sta 2765, 12 Jan 1888, 1 specimen (USNM 50729).

NORTH CAROLINA. 34°23′N, 75°54′W, 160 m, J.H. Day, collector, 30 Nov 1965, 1 specimen (USNM 50706, as Polyodontes lupina by Day, 1973).

PUERTO RICO. Mayaguez Harbor, 13 and 139 m, USS Fish Hawk sta 6059 and 6063, 19, 20 Jan 1899, 2 specimen (USNM 15679, 15962, as Panthalis oculea by Treadwell, 1901). Puerto Rico, 23 m, N. Hulings and D. Feray, collectors, 1963, 1 specimen (USNM 42752). Barceloneta, 18°30′41″N, 66°11′26″W, Interstate Electronic Corp sta 731–010–003, 10 Jan 1980, 293 m, 1 specimen (USNM 98808).

TYPE MATERIAL.—Holotype with 40 segments, last 2 small, regenerating, 17 mm long, and 6 mm wide with setae; pharynx completely extended. Figured specimen from Gulf of Mexico anterior fragment of 38 segments, 36 mm long, and 9 mm wide with setae.

DESCRIPTION.—Elytra round to oval, leaving middorsum uncovered, delicate, translucent, with flecks of pigment or dusty crescents of inner sides of elytra, with lateral pouch from 4th elytra (Figures 83B–D, 85B–E; Hartman, 1939b, pl. 25: fig. 304).

Prostomium bilobed, with bulbous ommatophores and long necks; median antenna with rounded ceratophore in middle of prostomium, with 2–3 pairs of lateral papillae, continuing posteriorly as raised ridge, with tapering style extending about to tips of ommatophores; pair of small eyes lateral to ceratophore of median antenna; lateral antennae inserted ventral to ommatophores, similar to median antenna; ventral palps stout, long, tapering, smooth (Figures 83A, 85A; Hartman, 1939b, pl. 25: fig. 300). Tentacular segment distinct dorsally, tentaculophores lateral to prostomium, each with row of papillae on inner side, 2 acicula, with or without few setae, and pair of dorsal and ventral tentacular cirri, similar to median antenna (Figures 83A, 85A,F; Hartman, 1939b, pl. 25: fig. 300).

Second segment with first pair of elytrophores, ventral buccal cirri much longer than following ventral cirri, and biramous parapodia longer than parapodia of segment 3; notopodium with digitiform acicular lobe and bundle of long capillary, finely spinous notosetae; neuropodium rounded, flared distally, with ventral bract; neurosetae numerous, slender, slightly wider basally, tapering to finely spinous capillary tips (Figures 83E–G, 85G,H; Hartman, 1939b, pl. 25: fig. 302). Distal border of extended pharynx with 13–15 pairs of papillae, middorsal and midventral ones on wide lobulated bases, middorsal one much longer than others, midventral one about one-third as long as middorsal one; 2 pairs of hooked jaws, each with 4–7 lateral teeth.

Third segment with first pair of dorsal cirri with short cirrophores and styles extending beyond setae; notopodium and notosetae similar to those of segment 2; neuropodium truncate with well-developed ventral bract; upper neurosetae slender, lanceolate, finely spinous; middle neurosetae stout, acicular, aristate; lower neurosetae slightly curved, with larger spines basally and close-set spinous rows distally (Figures 83H–K, 85I–K; Hartman, 1939b, pl. 25: fig. 303). Parapodia of segments 4–8 with smaller rounded notopodia and fewer short notosetae; neuropodia becoming larger, with more numerous neurosetae of same types (Figure 84A,B).

Beginning with segment 9, notopodium wide, rounded, flattened, on anterodorsal half of larger neuropodium, with notoaciculum, spinning gland, and row of short capillary notosetae; neuropodium with slightly bilobed presetal acicular lobe, truncate postsetal lobe, and anteroventral bract; lower neurosetae, within anteroventral bract, similar to more anterior parapodia; middle neurosetae stout, acicular, aristate, with slightly hooked tips, some with subdistal spines on one side; upper neurosetae of 2 types: (a) longer, lanceolate, with numerous spinous rows, tapering to capillary tips; (b) short, more slender, bipinnate, with short sharp tips (Figures 84C–F; 85L–N). More posterior parapodia larger with more numerous neurosetae; dorsal cirri with cirrophores inflated, with wider, shorter styles; stout acicular aristate neurosetae with more numerous subdistal spines on one side (Figures 84G–K, 86A–G; Hartman, 1939b, pl. 25: figs. 301, 305–308). Parapodial branchiae absent on type; single branchia present on some posterior parapodia of some specimens (Figure 86F).

DISTRIBUTION.—Panama (Pacific), North Atlantic off North Carolina, Caribbean (off Cuba, Puerto Rico), Gulf of Mexico, South Atlantic off Argentina. In 13 to 914 meters.