Malmgrenia andreapolis McIntosh 1874

Malmgreniella andreapolis (McIntosh, 1874)

Laenilla glabra Malmgren, 1865:73 [part, not same as lectotype].

Malmgrenia andreapolis McIntosh, 1874b:195; 1876a:377, pl. 67: figs. 20–23; 1900:382, pl. 28: fig. 8; pl. 31: fig. 3; pl. 33: fig. 11; pl. 40: figs. 27–30.

Harmothoe synaptae Saint-Joseph, 1906:147, pl. 1: figs. 1–6. [New synonymy.]

Harmothoe lunulata.—Cuénot, 1912:102, figs. 23–26.—Southern, 1914:52.—Orton, 1923:861, fig. 1 [part].—Cazaux, 1968:506, figs. 7, 8. [Not Delle Chiaje, 1830.]

Harmothoe lunulata var. andreapolis.—Fauvel, 1923:72, fig. 26k–o.

Harmothoe lunulata var. synaptae.—Fauvel, 1923:73.

Malmgrenia lunulata.—Pettibone, 1953:25 [part; not Delle Chiaje, 1830].

Harmothoe lunulata, var. E.—Spooner in Plymouth Marine Fauna, 1957:xxxviii, 112.

Malmgrenia castanea.—Amanieu and Cazaux, 1963:168 [not McIntosh, 1876a].

Harmothoe andreapolis.—Tebble and Chambers, 1982:49, figs. 16a–d, 46, 47.—Hanley, 1987:151, fig. 3D.

MATERIAL EXAMINED.—NORTHEASTERN ATLANTIC OCEAN: Sweden: Gullmaren, S. Lovén, collector, 1 specimen mixed with lectotype of Laenilla glabra Malmgren (NRS 5752). Scotland: St. Andrews, washed ashore after storms and in stomachs of cod and haddock, 17 syntypes of Malmgrenia andreapolis (BMNH 1921.5.1.5.0–511; USNM 54161). England: Plymouth area, var. E, with ophiuroid Acrocnida brachiata (Montagu): Salcombe, east side, G.M. Spooner, collector, 7 small specimens (LCHP–S-7); Salcombe, west side, 16 Mar 1966. P.E. Gibbs, collector, 4 small specimens (LCHP–G-5, USNM 55049). Plymouth area, var. E. synaptae, with Leptosynapta bergenensis (as L. inhaerens): Salcombe, west side, 26 Mar 1952, G.M. Spooner, collector, 1 specimen (LCHP–S-12); Salcombe, west side, 16 Mar 1968, P.E. Gibbs, collector, 2 specimens (LCHP–G-6; USNM 55050). Plymouth area var. E, with synaptid Labidoplax digitata (Montagu): Salcombe, east side, 25 Mar 1955, G.M. Spooner, collector, 1 specimen (USNM 55048, from LCHP–S-9); Salcombe, west side, 28 Mar 1967, P.E. Gibbs, collector, 1 specimen (LCHP–G-9). France: Terrenez, off Roscoff, commensal with synaptid, 15 Sep 1913, 1 specimen (MNHN).

TYPE MATERIAL.—Syntypes of M. andreapolis all fragmented, consisting of 17 anterior, 9 middle, and 2 posterior fragments. Anterior and posterior fragments of 12 and 23 segments, totaling 37, 25 mm long and 7 mm wide including setae. Pharynx extended on one of syntypes.

NONTYPE MATERIAL.—Larger specimens from Plymouth area, with synaptids, 18–29 mm long, 6–9 mm wide including setae, with 37–38 segments. Smaller specimens, with ophiuroids, 11–13 mm long, 4.5 mm wide, with 35–37 segments; smallest specimen 6 mm long, 3 mm wide, with 27 segments. Small specimen from Sweden 12 mm long, 5 mm wide, with 36 segments.

DESCRIPTION.—Body flattened, tapering slightly anteriorly and more so posteriorly. Dorsum of posterior segments with 2 dark bands per segment; posterior 10–15 segments ventrally with characteristic color pattern (Figure 17M; Cuénot, 1912, fig. 25). Fifteen pairs of elytra, large, soft, completely covering dorsum; first pair oval, with narrow dark band near anterior border, complete circle and dark spot on place of attachment to elytrophore, and some scattered micropapillae (Figure 17B); following elytra subreniform to oval, with complete or nearly complete circular band on posterior half and band of microtubercles near anterior border (Figure 17C,D; McIntosh, 1900, pl. 33: fig. 11); more posterior elytra without microtubercles and with pigmentation scattered, less concentrated (Figure 17E).

Bilobed prostomium with anterior lobes wide, truncate; eyes rather small, anterior pair anterolateral, about twice as large as posterodorsal pair; ceratophore of median antenna large, in anterior notch, with style about as long as prostomium; ceratophores of lateral antennae inserted terminoventrally, with styles short, subulate; antennae darkly pigmented, with scattered minute papillae; palps stout, tapered, smooth, variable in length; tentaculophores with 0–1 seta on inner side and pair of dorsal and ventral tentacular cirri, similar to median antenna (Figure 17A; McIntosh, 1900, pl. 28: fig. 8; Cuénot, 1912, fig. 26; Hanley, 1987, fig. 3D). Biramous parapodia of segment 2 with long ventral buccal cirri similar to tentacular cirri; notosetae similar to those following; neurosetae more slender than those following, upper and lower ones with entire bulbous tips, middle ones with long bare regions and bifid tips (Figure 17A,F,G). Extended pharynx with 9 pairs of border papillae and 2 pairs of reddish amber-colored jaws.

Notopodium short, rounded, with projecting acicular lobe on lower side; neuropodium with subconical presetal acicular lobe with thick digitiform supraacicular process and shorter rounded postsetal lobe (Figure 17H,I). Notosetae moderate in number, short to long, extending to about tip of neuropodia; slender, translucent, similar in size to neurosetae, with faint spinose rows and rounded bulbous tips (Figure 17J; McIntosh, 1900, pl. 40: fig. 27). Neurosetae moderate in number, forming fan-shape bundle, long, translucent; upper supraacicular neurosetae with longer spinose regions and entire bulbous tips and lower supraacicular neurosetae with secondary tooth (Figure 17K); upper subacicular neurosetae stouter, with shorter spinose regions, slightly hooked tips with secondary tooth, and lower ones with single knobbed tips (Figure 17L; McIntosh, 1900, pl. 40: figs. 28–30). Cirrophores of dorsal cirri long, cylindrical; styles tapered, extending to about tips of neurosetae, with scattered clavate papillae; dorsal tubercles nodular; ventral cirri short, subulate, with few clavate papillae (Figure 17I). Pygidium dorsal, medial to bases of small posterior parapodia, with pair of long anal cirri.

BIOLOGY.—In the Plymouth area, Spooner in Plymouth Marine Fauna (1957:112) and Orton (1923:861, fig. 1) observed Malmgreniella andreapolis (as Harmothoe lunulata var. E, with a strong circular pattern) commensal in the burrows of echinoderms. Smaller specimens were found with the ophiuroid Acrocnida brachiata (Montagu) whereas larger specimens were associated with the synaptids Leptosynapta galliennii (Herapath) (as L. inhaerens and L. bergenensis) and Labidoplax digitata (Montagu), hence M. andreapolis apparently changes hosts.

In Arcachon, France, Cuénot (1912:102, figs. 23–26) found the polynoids (as Harmothoe lunulata) living commensally with synaptids. The polynoids were found in the galleries excavated in the sand by the synaptids, crawling either on the body of its host or on the wall. When touched or when the water was agitated, the polynoids showed very brilliant white greenish luminescence.

Cazaux (1968:506–510, figs. 7, 8) studied the early development of the species (as Harmothoe lunulata) from the eggs to trochophores, metatrochophores I and II, nectochaetes I and II until when, after 3 weeks, they reached 10 segments and a length of 1.7 mm. Cazaux also noted that adults were very abundant on beaches of Arcachon with synaptids and were found in the galleries and along the walls of the hosts.

DISTRIBUTION.—Northeastern Atlantic Ocean from Sweden to France. Intertidal.