Malmgreniella scriptoria (Moore 1910)

Malmgreniella scriptoria (Moore, 1910)

Harmothoe scriptoria Moore, 1910:344, pl. 28: figs, 13–17.—Hartman, 1955:174; 1961:49; 1966:402; 1968:85, figs. 1–5.—Loi, 1980:124.

Malmgrenia lunulata.—Pettibone, 1953:25 [part], pl. 9: figs. 73–76; pl. 10: figs. 78, 79, 83, 84, 86; pl. 11: figs. 88–91.—Banse et al., 1968:525 [part].—Lie. 1968:271, 279, 370 [part; sta 2]. [Not Delle Chiaje, 1830.]

MATERIAL EXAMINED.—EASTERN PACIFIC OCEAN: California: Monterey Bay, off Point Pinos Light, Albatross sta 4460, 12 May 1904, 101–305 m, green mud and gravel, from ambulacral groove of spatangoid, holotype of Harmothoe scriptoria (USNM 17156). Washington: Puget Sound, off Skiff Point, Bainbridge Island, 254 m, mud with heart urchin Briaster townsendi, 17 Jul and 2 Aug 1938, M. Pettibone, collector, 14 specimens (USNM 24928, as M. lunulata by Pettibone, 1953). Puget Sound, Point Richmond, 73 m, gravel, mud and shell, 4 Jul 1940, M. Pettibone, collector, 7 specimens (USNM 24927, as M. lunulata by Pettibone, 1953). Puget Sound, off Port Madison, 47°42′N, 122°26′W, 172–216 m, fine soft mud, with many Briaster townsendi Agassiz, sta 2, haul 7, 21 May 1963, U. Lie, collector, 4 specimens (USNM 36443, as M. lunulata form B by Banse et al., 1968).

DESCRIPTION.—Holotype, female with eggs, in 2 pieces, 16 mm long, 5.5 mm wide including setae, and 39 segments, last one minute. Specimens from Puget Sound area off Skiff Point 10.5–14 mm long, 3.5–5 mm wide, with 34–38 segments. Specimens from Point Richmond 18–22 mm long, 5–6 mm wide, with 37–40 segments.

Body flattened, tapering slightly anteriorly and posteriorly. Elytra 15 pairs, on usual segments, oval to subreniform, thin, delicate, smooth, except for small group of microtubercles on anterior part (absent on 1st and some posterior elytra) and scattered round micropapillae (Figure 44B–E). Elytra opaque, with complete or incomplete circle of brown color on 1st elytral pair, following elytra with color confined to semicircular area on posterior and medial sides, plus pigmented spot over place of elytral attachment (Figure 44B–D; Moore, 1910, pl. 28: fig. 15; Pettibone, 1953, pl. 9: fig. 73; pl. 10: figs. 78, 79).

Bilobed prostomium with anterior lobes truncate or wide subtriangular, without distinct peaks; eyes rather small, anterolateral pair slightly larger than posterodorsal pair; ceratophore of median antenna large, bulbous, with style longer than prostomium; ceratophores of lateral antennae inserted terminoventrally, converging midventrally, with styles less than half as long as median antenna; palps stout, tapered; tentaculophores lateral to prostomium with 0–1 seta on inner side; dorsal and ventral tentacular cirri similar to median antenna; styles of antennae and tentacular cirri with minute papillae and pigmented on basal half (Figure 44A; Moore, 1910, pl. 28: fig. 13; Pettibone, 1953, pl. 9: figs. 75, 76). Segment 2 with first pair of large elytrophores, biramous parapodia, and long ventral buccal cirri similar to tentacular cirri (Figure 44A,F); notosetae similar to those following; neurosetae more slender than those following, with bulbous tips, upper ones each with secondary tooth (Figure 44G).

Biramous parapodia with notopodium short, rounded, with projecting acicular lobe on lower side; longer neuropodium with subconical presetal acicular lobe with wide supraacicular process and shorter, rounded postsetal lobe (Figure 44F,H,I; Moore, 1910, pl. 28: fig. 14; Pettibone, 1953, pl. 10: figs. 83, 84). Notosetae moderate in number, about as stout as neurosetae, short and longer, with faint spinose rows, tapering to blunt bare tip (Figure 44J; Moore, 1910, pl. 28: fig. 17; Pettibone, 1953, pl. 10: fig. 86). Neurosetae moderate in number, upper ones with longer spinose region, upper few with entire tip, rest with distinct secondary tooth; middle ones with shorter spinose region and bifid tip; some lower ones with or without small secondary tooth (Figure 44K; Moore, 1910, pl. 28: fig. 16; Pettibone, 1953, pl. 11: figs. 88–91). Dorsal cirri with cylindrical cirrophore and long style, extending beyond tips of neurosetae, with minute papillae and pigmentation on basal half; dorsal tubercles nodular; ventral cirri short, subulate (Figure 44I; Pettibone, 1953, pl. 10: fig. 83). Pygidium with anus medial to last pair of small parapodia, with pair of anal cirri.

BIOLOGY.—The type specimen of M. scriptoria from Monterey Bay was collected from the ambulacral groove of a spatangoid. In the Puget Sound area, specimens were found by M. Pettibone occupying the ambulacral groove of the heart urchin Briaster townsendi Agassiz, where they were well protected by the ambulacral spines of the host. In the revision of Briaster by Markov (1989:87), Briaster townsendi Agassiz, 1898 is referred to as B. latifrons Agassiz, 1898.

DISTRIBUTION.—Eastern Pacific Ocean, from Washington, Puget Sound to southern California, in 42–373 meters (see Hartman, 1968).