Scyphoproctus pseudoarmatus ( Silva, 1965 ) Amended

Silva, Camila Fernanda Da & Amaral, Antonia Cecilia Zacagnini, 2019, Scyphoproctus Gravier, 1904 (Annelida, Capitellidae): description of three new species and relocation of Heteromastides Augener, 1914 in Scyphoproctus, Zootaxa 4560 (1), pp. 95-120 : 103

Scyphoproctus pseudoarmatus ( Silva, 1965) Amended

( Figure 4 )

Pulliella pseudoarmata Silva, 1965: 555 ̅556; fig. 11a̅e.

Scyphoproctus pseudoarmatus— Magalhães & Bailey-Brock 2012: 42 (new combination).

Material examined. Scyphoproctus pseudoarmatus ( Silva, 1965) , holotype BMNH 1963.14.8—Kalkuda, Ceylon, Sri Lanka, shallow tide pools, 1 spec.

Description. Body rounded; anterior thorax slightly wider than abdomen ( Fig. 4A ). Brownish color in alcohol.

Prostomium short, rectangular, with rounded anterior end, 1.5x longer than wide ( Fig. 4A ); nuchal organs not observed; eyespots absent. Peristomium 3x longer than thoracic chaetigers, border with achaetous segment 1.5x wider than anterior edge ( Fig. 4D ). Incomplete inter-segmental groove between peristomium and achaetous segment ( Fig. 4D ).

Thorax with 15 segments, including the peristomium, one additional achaetous segment, and 13 chaetigers. Bilimbate capillaries in noto- and neuropodia of chaetigers 1–12, hooded hooks in noto- and neuropodia of chaetiger 13. Thorax smooth with chaetigers biannulate; moderate depth of inter-segmental grooves between chaetigers. First chaetiger biramous. Parapodial lobes well-separated; notopodia inserted dorso-laterally and neuropodia neuro-laterally ( Fig. 4D ). Lateral organs absent or not conspicuous. Transition between thorax and abdomen conspicuous, marked by constriction, chaetal change and appearance of parapodial lobes ( Fig. 4 A–B).

Abdominal chaetigers without capillaries. Abdominal notopodium and neuropodium with well-developed tori pads. First notopodial lobes larger and almost together, distance between lobes increasing along the abdomen, and width of lobes decreases ( Fig. 4B ); short distance between neuropodial lobes, nearly the same distance throughout the abdomen ( Fig. 4C ). Hooded hooks not observed because it was not allowed to remove any tissue from the specimen.

Seven pre-pygidial segments with neuropodial hooks and notopodial spines (11,10, 10, 9,9,7,5, each side), greater number of spines near plaque; first three pre-pygidial segments (toward the anal plaque) with dorsal edges of segment triangular with a filamentous tip, one of transition, and three with rounded edges ( Fig. 4E ). Anal plaque well-developed formed by two fused chaetigers; rounded, with thin and foliage border; plaque with the sets of acicular spines in horizontal rows protruding midway on each side of the plaque, not reaching the plaque margin (6,5, each side). Small and terminal anus, on the base of the membrane ( Fig. 4F ). Two short and thin cirri, 4– 5x longer than wide; median triangular membrane, posterior border (where cirri emerge) 1.2x wider than anterior margin (near anus) ( Fig. 4F ).

Remarks. Magalhães & Bailey-Brock (2012) synonymized the genus Pulliella with Scyphoproctus with the description of the new species Scyphoproctus edmondsoni , which also presented a poorly developed anal plaque. The authors suggested that type material of Scyphoproctus pseudoarmatus should be revised in order to confirm if the anal plaque of this species was well- or poorly developed. According to drawings of the original description, it seems that the anal plate is poorly developed; however, reexamination of the type specimen made possible to confirm that S. pseudoarmatus presents a well-developed anal plaque with sets of acicular spines in horizontal rows protruding midway on each side of the plaque, not reaching the plaque margin. It was also possible to certify the presence of the achaetous segment, not mentioned in the original description.

Figures

FIGURE 4. Scyphoproctus pseudoarmatus. (A) Anterior end, lateral view; (B) Anterior end, dorsal view; (C) Anterior end; ventral view; (D) Anterior end, lateral view; (E) Posterior end, lateral view; (F) Posterior end, frontal view. Scale bars: A, B, C, 1 mm; D, E, F, 0.5 mm.