Revision of Autolytinae (Syllidae: Polychaeta).
Author
Nygren, Arne
text
Zootaxa
2004
680
1
314
journal article
42299
10.5281/zenodo.157809
43595c87-02cf-47ba-ba28-0cb07de78adc
1-877354-52-X
157809
471A4E52-4C92-44F8-AB38-CD03071C0067
Procerastea
Langerhans, 1884
Procerastea
Langerhans, 1884
: 249
–250, fig. 5A–E.
Linnean name definition
.
Type
species
Procerastea nematodes
Langerhans, 1884
by monotypy.
PhyloCode definition
. No name definition provided.
Apomorphies
. Clade supported by a single morphological character (
Fig. 4
):
simple chaetae in median and posterior chaetigers absent
(character 29), character state change is a reversal, and a parallelism, later changed within clade.
General description
.
Atokous form
. Length
1.8–7.4 mm
for 31–55 chaetigers (up to
25 mm
(Allen 1921))
; width, measured at level of proventricle and excluding parapodial lobes,
0.15–0.3 mm
. Body shape, excluding parapodial lobes, cylindrical in transection, venter flattened; body width fairly constant with tapering end. Body in outline nearly threadlike, due to small parapodial lobes and absence of dorsal cirri from chaetiger 2. Ciliation absent, except for nuchal epaulettes (unknown for some taxa). Prostomium rounded rectangular, wider than long. Four eyes, with lenses, in trapezoid arrangement, anterior pair larger. Eyes confluent or separated, eye spots absent. Palps fused, small, in dorsal view not projecting in front of prostomium, or projecting 1/5 of prostomial length. Nuchal epaulettes maximally extending to end of tentacular segment.
Prostomium with 3 antennae; median antenna inserted medially on prostomium, lateral antennae on anterior margin. Tentacular cirri 2 pairs. Dorsal cirri only present on first chaetiger. Appendages club shaped or cylindrical. Except for bayonet chaetae, simple chaetae present in chaetiger 1–4, or in all chaetigers. Compound chaetae present from chaetiger 1, chaetiger 2, or absent. Both simple chaetae and compounds uni or bidentate with small distal tooth; blade serration absent. Single thick, distally dilated, bayonet chaetae, with distal denticulation.
Pharynx with very small sinuation, or with one to several small sinuations anterior to proventricle. Trepan teeth arranged in 1 ring, with 6–30 equal teeth. Basal ring absent; infradental spines absent. Proventricle with varying number of rows of square shaped muscle cells. Pygidium with 2 cirri (reported length compared to body width, excluding parapodial lobes, at level of proventricle if not otherwise stated), median papilla absent.
Epitokes
.
Male
. See description under
Procerastea halleziana
Malaquin, 1893
.
Female
. See description under
Procerastea halleziana
.
Procerastea australiensis
HartmannSchröder, 1987
(Fig. 40A–C)
Procerastea australiensis
HartmannSchröder, 1987
: 45
–46, figs 23–31.
Material examined
.
Australia
:
holotype
ZMH
P
18863, Point Lonsdale at Geelong, intertidal, algae and sand
24 Dec 1975
; 1
paratype
ZMH
P
18864, Wilson's promontory, Lenoard Bay, cliff on northern squeaky beach, intertidal, algae and crusts,
27 Dec 1975
.
Diagnosis
.
Procerastea
with bidentate simple chaetae together with compounds in anterior 4 chaetigers; trepan with 6 indistinct teeth.
Description
.
Holotype
complete, length
1.8 mm
for 31 chaetigers (1.8 for 32 chaetigers in
paratype
), width
0.15 mm
. Preserved material whitish, no colour markings. Ciliation not possible to assess.
Eyes separated (Fig. 40A); eye spots absent. Palps small, do not project in front of prostomium (Fig. 40A), fused. Nuchal epaulettes reaching over tentacular segment.
Median antenna reaching chaetiger 3–4. Lateral antennae 1/2 as long as median antenna. Dorsal tentacular cirri and first dorsal cirri 2/
3 in
length of lateral antennae. Ventral tentacular cirri 1/2 as long as dorsal pair. Dorsal cirri from chaetiger 2 absent. Small indistinct cirrophores on tentacular cirri and first dorsal cirri present. Appendages clavate (Fig. 40A).
Parapodial lobes small, rounded conical. Single acicula in all chaetigers. Chaetiger 1– 4 with 1 or 2 compounds and 2 simple chaetae (Fig. 40B), following chaetigers with 2–3 compounds (Fig. 40C). Compounds as well as simple chaetae with small distal tooth (Fig. 40B, C); serration absent. Single thick bayonet chaetae, distally dilated (Fig. 40B, C), beginning at chaetiger 1.
Pharynx with small sinuations anterior to proventricle (Fig. 40A). Trepan in tentacular segment (Fig. 40A) or chaetiger 1, with c. 6 indistinct teeth. Basal ring absent; infradental spines absent. Proventricle equal in length to 2 segments in chaetiger 4–6 with c. 20 indistinct rows of muscle cells. Anal cirri, as long as ventral tentacular cirri.
Reproduction
. Unknown.
Habitat
. Intertidal, algae, crusts.
Distribution
. South West Pacific. South East
Australia
Remarks
.
Procerastea australiensis
is almost identical to
P. nematodes
Langerhans, 1884
. Number of chaetae is less in
P. australiensis
, at the most five in anterior chaetigers, compared to
9–13 in
P. nematodes
; in addition the pharynx is also more convoluted in
P. australiensis
than in
P. n e m a t o d e s
.