Polyodontes tidemani Pflugfelder 1932

Polyodontes tidemani Pflugfelder, 1932

Polyodontes tidemani Pflugfelder, 1932a:286, figs. 6, 7; 1932b:559, figs. 10, 13–15; 1934, figs. 3, 4, 10–12.

MATERIAL EXAMINED.—INDONESIA. S.E. of Rumadan Island, 05°30′S, 132°46′E, 46–51 m, mud, Muriel King Memorial Expedition to Moluccas, L.M. Joll, collector, 12 Jun 1970, 1 specimen (WAM 63–86).

TYPE MATERIAL.—The type of Polyodontes tidemani from the Moluccas was not available. The specimen collected by L.M. Joll seems to agree with the description and figures by Pflugfelder and is described here. It consists of an anterior fragment of 25 segments, 18 mm long, and 11 mm wide with setae; the pharynx was not extended but was cut open.

DESCRIPTION.—Only left first elytron remaining, large, smooth, finely areolate; 2nd pair of elytra shown on figure by Pflugfelder, leaving middorsum uncovered (Figure 78A; Pflugfelder, 1932a, fig. 6). Prostomium bilobed, with bulbous ommatophores with distal lenses and long necks; median antenna with ceratophore in middle of prostomium, with few lateral papillae, continuing posteriorly as raised ridge, with style extending almost to tips of ommatophores; posterior pair of small eyes lateral to ceratophore of median antenna; lateral antennae inserted ventrally, with tips extending beyond ommatophores and visible dorsally, ventral palps stout, tapering, about 3 times longer than median antenna, with 4 or 5 longitudinal rows of long papillae (Figure 78A; Pflugfelder, 1932a, fig. 6). Tentacular segment distinct dorsally (hidden from view on Figure 78A due to partial withdrawal of head end into anterior segments); tentaculophores lateral to prostomium, each with 2 acicula, 2 sharply projecting acicular lobes, 2 bundles of capillary setae, and pair of dorsal and ventral tentacular cirri, similar to median antenna (Figure 78A,B; Pflugfelder, 1932a, fig. 6).

Second segment with first pair of elytrophores, ventral buccal cirri longer than following ventral cirri, and biramous parapodia; notopodium with digitiform acicular lobe on anterodorsal face of larger neuropodium, with bundle of long, finely spinous capillary notosetae; neuropodium wide, subconical with anteroventral bract; neurosetae slightly enlarged basally, with spinous rows, tapering to capillary tips, lower ones shorter, with more prominent spines (Figure 78A,C–E). Pharynx (cut open) with 17 pairs of border papillae, middorsal and midventral ones on wide lobulated bases, middorsal one much longer than others, midventral one only slightly longer, 2 pairs of hooked jaws each with 5–7 lateral teeth.

Third segment with first pair of dorsal cirri with short cirrophores and styles extending beyond setae; parapodia similar to segment 2 except for appearance of middle stout acicular neurosetae (Figure 78F–H). Following parapodia of segments 4–8 with notopodia becoming smaller and shorter notosetae (Figure 79A).

Beginning with segment 9, notopodium wide, rounded, flattened, on anterodorsal half of larger neuropodium, with notoaciculum, spinning glands, and row of short capillary notosetae; neuropodium with slightly rounded presetal acicular lobe and truncate postsetal lobe, with slightly developed anteroventral bract; lower group of neurosetae numerous, rather slender, curved, enlarged basally with larger spines, tapering to capillary tips with close-set spinous rows; middle stout acicular neurosetae with slightly hooked tips, without aristae; upper group of neurosetae, emanating from low anterodorsal bract, hidden by notopodium, of 2 types: (a) long, slender, wider basally, tapering to slender tips, thickly spinous; (b) shorter, more slender, wider basally, tapering to shart tips, with widely spaced bipinnate spines (Figure 79B–F).

Middle parapodium becoming larger, with more numerous setae of same types; dorsal cirri with wider cirrophores and shorter styles; some acicular neurosetae with subdistal spines on one side; digitiform branchiae in region of elytrophores and dorsal cirrophores beginning on segment 10 and continuing to end of fragment (segment 25); inflated branchial areas medial to ventral cirri beginning about segment 13 (Figure 79G–I; Pflugfelder, 1932a, fig. 7a–d).

TUBES.—According to Pflugfelder (1932a:286), the tubes extended above the bottom by about 5–10 cm and were plainly visible in the clear water. It was difficult to collect the worms, which pulled back into the deeper parts of their tubes. The tubes had a fine uniform structure.

DISTRIBUTION.—Indonesia (Moluccas). In low water to 51 meters.