Pseudoscalibregma bransfieldium ( Hartman, 1967 )

Blake, James A., 2015, New species of Scalibregmatidae (Annelida, Polychaeta) from the East Antarctic Peninsula including a description of the ecology and post-larval development of species of Scalibregma and Oligobregma, Zootaxa 4033 (1), pp. 57-93 : 79

Pseudoscalibregma bransfieldium ( Hartman, 1967)

Figure 6 F‒G

Eusclerocheilus bransfieldia Hartman, 1967: 130 ‒131, pl. 39

Hyboscolex bransfieldia: Kudenov & Blake, 1978: 440 .

Pseudoscalibregma bransfieldia: Hartman, 1978: 180 ‒181, fig. 28

Pseudoscalibregma bransfieldium: Blake, 1981: 1143 ‒1145, fig. 6; Hartmann-Schröder & Rosenfeldt, 1991: 75.

Material examined. East Antarctic Peninsula, RVIB Nathaniel B. Palmer Cruise 2000-03, Collector, J.A. Blake. —Larsen-A Ice Shelf Area, transect along border with Larsen B, Sta. NBP- 10, 332 m, 1 specimen ( LACM- AHF Poly 7010).

Additions to description. Single specimen complete, 10 mm long, 3 mm wide with 22 setigers; the body more maggot-shaped than arenicoliform. In alcohol, color light tan with no body pigment.

Prostomium bears two long frontal horns projecting anterolateral; dorsal surface of prostomium somewhat domed or elevated, clearly visible; eyes absent; nuchal organs not apparent. Peristomium a single dorsal ring surrounding the prostomium dorsally; ventrally forming upper and lower lips of mouth with upper lip relatively smooth and lower lip with three weakly developed lobes. A weakly developed ventral groove apparent along body from setiger 4; initially, groove formed by a single large segmental annulus that at the mid-point produces a notch between segments; in last 5‒6 segments, a distinct furrow develops at segmental mid-point. The pygidium damaged, but bears five anal cirri.

Anterior parapodia weakly developed with low noto- and neuropodia; posteriorly podial lobes elongate, apically pointed, bearing distinctive dorsal and ventral cirri ( Fig. 6 G), both of which are bulbous extensions of the podial lobes; internal glands absent from cirri and elsewhere on body. Interramal papillae weakly developed.

Setae consist of numerous capillaries arranged in 2‒3 rows throughout; lyrate setae from setiger 2; setiger 1 bears an anterior row of short, thin, spinous setae ( Fig. 6 F) anterior to capillaries, the homologues of lyrate setae now known to occur on numerous species of Scalibregmatidae .

Remarks. Pseudoscalibregma bransfieldium differs from other scalibregmatids by the distinctive dorsal and ventral inflated extensions of the podial lobes. The short anterior spinous setae of setiger 1 are newly reported.

Distribution. Widespread in Antarctic seas 332‒ 916 m.

Figures

FIGURE 6. Pseudoscalibregma palmeri n. sp. Holotype, Sta. NBP- 03 (LACM-AHF-Poly 7009): A, anterior end, dorsal view; B, anterior end, ventral view; C, detail of interparapodial papilla; D, short spinous setae from setiger 1; E, lyrate seta from middle body setiger. — Pseudoscalibregma bransfieldium: F, short spinous setae from setiger 1; G, posterior parapodium, anterior view. Abbreviations: dC, dorsal cirrus, intP; interramal papilla; lL, lower lip of mouth; neP, neuropodium; noP, notopodium, per, peristomium; pr, prostomium; uL, upper lip of mouth, vC, ventral cirrus; vG, ventral groove.