Anguillosyllis capensis Day, 1963

Maciolek, Nancy J., 2020, Anguillosyllis (Annelida: Syllidae) from multiple deep-water locations in the northern and southern hemispheres, Zootaxa 4793 (1), pp. 1-73 : 14-15

Remarks on Anguillosyllis capensis Day, 1963

Day’s (1963) original description of the genus Anguillosyllis from 183 m on the Agulhas Bank off South Africa referenced large palps that were fused for “over half their length;” in his original illustration of the type species, A. capensis , he indicates an obvious furrow in the distal end of the otherwise closely applied palps. However, in his monograph ( Day 1967), the illustration shows an obvious separation of the distal tips of the palps; this separation is also indicated in the drawing by Aguado & San Martín (2008). Other characters of the holotype included a maximal length of 3.5 mm; 12 segments (the other available specimen was described as having 13 segments, so the number of setigers of this species is uncertain); three short club-shaped antennae; two smaller tentacular cirri; a barrel-shaped proventriculus that occupied three setigers and had about 30 rows of points; long dorsal cirri on all setigers including setiger 2; slender ventral cirri inserted distally on the parapodia; and compound falcigerous setae with minutely serrated blades and blunt unidentate tips. The most intriguing part of the description and the character that Day singled out as unique was the “curious dorsal hood” on the parapodium ( Day 1963: 401). Day further described this structure as tapering to a cirriform projection, which was all that was visible when the hood was retracted; the parapodia then appearing to have three points: anterior, posterior, and superior (i.e., dorsal). Day’s (1967) subsequent description of this species in his monograph on South African polychaetes included at least two lapsus calami when he referred to its 5-mm length and 30 segments. Further, palps were described therein as fused for half their length (rather than over half their length), and the “short” prostomial antennae became “minute papilliform” structures, as did the tentacular cirri. The setae were now described as long and fine and ending in a blunt, apical tooth, but the illustration indicates a serrated falciger with a blunt tip. Thus, there is a bit of confusion over the characters of the species that Day (1963) used as the type of his new genus.

Anguillosyllis capensis was not reported again until new syllid material was collected during the DIVA-1, DIVA-2, and BIOZAIRE projects. Böggemann & Purschke (2005) and Böggemann (2009) reported A. capensis from the Angola, Cape, and Guinea Basins off the west coast of Africa at depths of 3945–5672 m. After comparison with the holotype and paratype, the new material was said to “predominantly agree” with Day’s (1963) types but had up to 11 (10–11) setigers; compound setae with blades within each fascicle ranging in length from long spinigerlike setae to short falcigers; aciculae with pointed tips numbering anywhere from 2–7 in anterior setigers and 1–4 in posterior setigers; and superior and inferior simple setae in some specimens. The latter two characters (numerous aciculae and presence of simple setae) are especially striking differences from the original description. Böggemann & Purschke (2005) did not specifically comment on the presence or absence of dorsal cirri on setiger 2, but Böggemann (2009) illustrated basal cirrophores on all setigers, including setiger 2. Böggemann (2009) also illustrated five anal cirri, including a short digitiform medial cirrus on the ventral side in addition to two lateral pairs. Notably, Fig. 141A ( Böggemann 2009) shows a specimen with 11 setigers whereas Fig. 141B shows a specimen with 10 setigers; in light of results of the present study, these two figures likely represent different species.

Aguado & San Martín (2008) redescribed A. capensis based on an examination of the holotype, which by that time had lost all antennae and dorsal cirri and was reduced to six setigers. The possibly retractile superior parapodial lobes were interpreted as posterior lobes ( Aguado & San Martín 2008, Fig.1 B–C). Although they described setal blades of varying lengths, thus agreeing with Böggemann & Purschke’s (2005) observations of the material from the Angola Basin, they did not see aciculae or simple setae in the holotype. During a visit to the BMNH in 2007, Dr. J.A. Blake (pers. comm.) examined Day’s (1963) type material and found that only fragments of setigers remained; thus, the type material must now be considered useless for confirming additional characters.

In discussing the molecular analysis of material identified as A. capensis, Böggemann (2009: 415) speculated on the need to clarify whether he was dealing with a widespread species or a complex of cryptic species. It is likely that Böggemann’s (2009) deep SE Atlantic material represents at least two species, neither of which may be the original A. capensis . Further, Böggemann (2009: 405) suggested that A. capensis might be conspecific with A. palpata ( Hartman, 1967) ; however, the two species have different palp and parapodial structures and Böggemann’s suggestion is herein rejected (also see discussion on A. palpata below).

Figures

FIGURE 1. Anguillosyllis palpata (Hartman, 1967). ANDEEP sta.74-5 (SMF 24873): A, entire specimen dorsal view. AN- DEEP sta. 105-2 (SMF 24866): B, setiger 1, dorsal view.ANDEEP sta. 121-10 (SMF 24874): C, setiger 3, dorsal view. Gulf of the Farallones, SFDODS sta. 19 (CASIZ 230481), dorsal view: D, setiger 8; E, setiger 9; F, setiger 10; G, setiger 11. ANDEEP sta.74-5, (SMF 24873): H, two setae from same setiger. Abbreviations: acic—acicula, aL—anterior lobe, dC—dorsal cirrus, dL—dorsal lobe, MGst—cells stained with Methyl Green pL—posterior lobe, pVCa—post-ventricle caeca, InGl—internal gland, SeSac—setal sack, vC—ventral cirrus.