Anguillosyllis (Annelida: Syllidae) from multiple deep-water locations in the northern and southern hemispheres
Author
Maciolek, Nancy J.
text
Zootaxa
2020
2020-06-15
4793
1
1
73
journal article
21680
10.11646/zootaxa.4793.1.1
f31ec6ba-4ed8-4245-9ed0-c068cda2c03a
1175-5326
3896150
550F8461-03F6-4301-8791-605775D77467
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further described this structure as tapering to a cirriform projection, which was all that was visible when the hood was retracted; the parapodia then appearing to have three points: anterior, posterior, and superior (i.e., dorsal).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).