Stylobates birtlesi, Crowther, Andrea L., Fautin, Daphne G. & Wallace, Carden C., 2011

Crowther, Andrea L., Fautin, Daphne G. & Wallace, Carden C., 2011, Stylobates birtlesi sp. n., a new species of carcinoecium-forming sea anemone (Cnidaria, Actiniaria, Actiniidae) from eastern Australia, ZooKeys 89, pp. 33-48 : 34-36

Stylobates birtlesi sp. n. Figures 15

Material examined.

Holotype:

MTQ G57579 (one specimen) (Figure 1).

Type locality: 17°45.99'S, 148°39.09'E, 958-964 m; Coral Sea, off Tully, Queensland, Australia (FRV Franklin, Cidaris I expedition, Station 15-4). Bottom temperature 5.5°C, rocks/mud sediment. Collected 9 May 1986, by RA Birtles and P Arnold. Hermit crab present.

Paratypes:

MTQ G57580 (one specimen).

Locality: 17°52'S, 147°08'E, 680-740 m; Coral Sea, off Tully, Queensland, Australia (FRV Franklin, Cidaris I expedition, Station 48-3). Bottom temperature 8.2°C, mud sediment. Collected 17 May 1986, by RA Birtles and P Arnold. Hermit crab separated from carcinoecium, registered as QM W16502 (crustacean collection).

MTQ G57581 (two specimens).

Locality: 17°51.71'S, 147°09.93'E, 881-920 m; Coral Sea, off Tully, Queensland, Australia (FRV Franklin, Cidaris I expedition, Station 49-3). Bottom temperature 6.1°C, rocks/shell debris/sticky mud sediment. Collected 17 May 1986, by RA Birtles and P Arnold.

MTQ G57582 (one specimen).

Locality: 18°01.69'S, 147°20.53'E, 899-918 m; Coral Sea, off Tully, Queensland, Australia (FRV Franklin, Cidaris I expedition, Station 50-3). Bottom temperature 6.2°C, mud sediment. Collected 17 May 1986, by RA Birtles and P Arnold. Hermit crab separated from carcinoecium, registered as QM W16499 (crustacean collection).

KUDIZ 003352 (one specimen).

Locality: 18°01.69'S, 147°20.53'E, 899-918 m; Coral Sea, off Tully, Queensland, Australia (FRV Franklin, Cidaris I expedition, Station 50-3). Bottom temperature 6.2°C, mud sediment. Collected 17 May 1986, by RA Birtles and P Arnold. Hermit crab separated from carcinoecium, registered as QM W16499 (crustacean collection).

MTQ G64680 (four specimens).

Locality: 16°55'S, 151°34'E, 880 m; Coral Sea, northeast Queensland, Australia (RV Soela, Station CO685A78). Collected 6 December 1985, by P Davie. Hermit crabs separated from carcinoecia, registered as QM W16514 (crustacean collection).

Voucher:

MTQ G58760 (one specimen).

Locality: 27°59.37'S, 154°00.12'E, 590 m; off coast of southeast Queensland, Australia (FRV Iron Summer, Shot 2). Collected 31 March 1983, by R Morton.

Description.

Base: Pedal disc concave, attached to carcinoecium. Base of anemone covers most of carcinoecium, except part directly under hermit crab, presumably where hermit crab’s chelipeds frequently contact carcinoecium (arrow, Figure 1f).

Column: Not cylindrical: wraps around gastropod shell so column much longer on one side than on diametrically opposite side. Smallest specimen with shortest side 4 mm, longest side 50 mm. Largest specimen with shortest side 15 mm, longest side 90 mm. Smooth, thin. Fosse shallow. Live specimens light pink, body wall translucent (Figure 1a, b); preserved specimens beige. Mesenterial insertions visible through body wall; white in live specimens (Figure 1a) and preserved specimens.

Oral disc: Oriented toward substrate in life, over umbilicus area (Figure 1c, d). Disc and mouth circular (Figure 1e); disc exposed and mouth agape in all specimens examined. Ectodermal musculature radial.

Orientation: Directive axis in line with spire of shell, parallel to parietal wall of aperture (dotted red line, Figure 1e).

Tentacles: Beige, slightly darker than column, no pattern. Relatively narrow, tip terete.96 to more than 200 in largest specimens; at margin, in 3 or 4 cycles. Not of uniform length: shortest ones (1-4 mm) on directive axis, at end of one siphonoglyph, beside longest ones (3-9 mm); tentacle length grades between them around oral disc (Figure 1e). Ectodermal musculature longitudinal (Figure 2).

Marginal sphincter muscle: Well developed, circumscribed, palmate (Figure 3a, b).

Mesenteries and internal anatomy: Two siphonoglyphs visible in most specimens; actinopharynx ribbed, darker beige than column. Mesenteries to five orders (Figure 4a); thin, each with oral but no marginal stoma. Retractor muscles diffuse (Figure 4b). Parietobasilar muscle with short free penon. Sexes presumably separate: three females, one male examined. First three orders complete and sterile, rest incomplete and fertile (Figure 4a).

Carcinoecium: Shape similar to that of dextral, trochoid gastropod shell. Aperture with simple arced elliptical outer lip, fairly straight parietal wall along what would be termed the columella in a gastropod. Bronze color, becomes chalky out of liquid.

Cnidae: Cnidom: Spirocysts, basitrichs, microbasic p-mastigophores. Table 1 lists distribution and size of cnidae; Figure 5 depicts each cnida type. The largest specimen (MTQ G57580) possessed small basitrichs (e)and(f) in the actinopharynx, and small basitrichs (h) in the column that were not found in other specimens.

Habitat: Mud and rocks, 590-694 m.

Distribution: From Coral Sea of northern Queensland to southern Queensland coast (Figure 6).

Symbiont: Hermit crab Sympagurus trispinosus (Balss, 1911), identified by Dr. Rafael Lemaitre (Curator of Crustacea , Department of Invertebrate Zoology, USNM).

Etymology.

This species is named for R Alastair Birtles of James Cook University, Townsville, who, with the late P Arnold (MTQ) and M Pichon (Australian Institute of Marine Science), collected this species and photographed it alive.