Two new and two poorly known autolytines (Polychaeta: Syllidae) from Madeira and the Mediterranean Sea
Author
Nygren, Arne
Author
Sundkvist, Tobias
Author
Mikac, Barbara
Author
Pleijel, Fredrik
text
Zootaxa
2010
2640
35
52
journal article
10.5281/zenodo.198574
bb995dc7-7406-40b7-9f65-e129631842fa
1175-5326
198574
Myrianida
Milne Edwards, 1845
Myrianida longoprimicirrata
(
López, San Martín & Jiménez, 1997
)
(
Figs 4
A–C, 5F–H)
Autolytus longoprimicirrata
López, San Martín & Jiménez, 1997
: 296
–298, fig. 2A–G;
San Martín 2003
: 492
–494, fig. 271A–F.
Myrianida longoprimicirrata
Nygren 2004
: 141
–142, fig. 69A–B.
Material examined.
Holotype
. Chafarinas Islands,
15 m
, in
Cladocora caespitosa
blocks,
15 Sept 1992
,
MNCN
16–01/2122.
Paratypes
. Same locality as
holotype
, two specimens (
MNCN
16–01/2122b).
Other material
.
Croatia
, Istria, Sv. Ivan,
45°02.755'N
13°37.422'E
,
5–15 m
,
Padina
and other algae,
SCUBA
,
19 Sept 2008
, two specimens preserved on slides (
GNM
Polychaeta 13214a, 13215), rear ends preserved in alcohol, of which one is used up for
DNA
extraction (
GNM
Polychaeta 13214b);
Croatia
, Istria, Banjol,
45°04.442'N
13°36.664'E
,
15–27 m
, precoralligene,
SCUBA
,
23 Sept
, 2008, two specimens preserved on slides (
GNM
Polychaeta 13216a, 13217a), rear ends preserved in alcohol (Polychaeta
GNM
13216b, 13217b);
Croatia
, Istria,
2 km
west of Rovinj,
45°05.220'N
13°36.517'E
,
27 m
, sponges, hydroids, and
Holothuria
sp., Agassiz trawl,
25 Sept 2008
, two specimens preserved in alcohol (
GNM
Polychaeta 13218, 13219);
Croatia
, Istria, St Andrew’s
Island
,
45°02.561'N
13°36.792'E
,
10–16 m
, precoralligene,
SCUBA
,
24 Sept 2008
, one specimens preserved in formalin (
GNM
Polychaeta 13220);
France
, Banyuls-sur-mer,
42°29.94’N
03°08.46’E
,
25 m
, corraligene,
SCUBA
,
7 April 2009
, two specimens preserved in alcohol of which one is used up for
DNA
extraction (
GNM
Polychaeta 13221), two specimens preserved on slides (
GNM
Polychaeta 13222a, 13223a), posterior ends preserved in alcohol (
GNM
Polychaeta 13222b, 13223b).
Diagnosis.
Myrianida
with long cirrophores on the long cirri from anterior chaetigers, and a trepan with 33–45 equal, or nearly equal, teeth.
Description.
Length
4–14 mm
for 43–124 chaetigers, width at level of proventricle, excluding parapodial lobes, c.
0.3 mm
. Live specimens yellowish to orange, with more or less distinct bands of orange glands across each segment, giving an orange-banded impression (
Fig. 4
A). Body shape, excluding parapodial lobes, cylindrical in transection, ventrally flattened. Body fairly constant in width, with tapering posterior end. Ciliation on nuchal epaulettes and as a single ciliary troch per segment. Prostomium rounded rectangular. Four eyes with lenses, anterior pair larger, confluent in dorsal view (
Fig. 4
B); eye spots absent. Palps in dorsal view projecting c. half the prostomial length (
Fig. 4
B), fused. Nuchal epaulettes extending to between beginning of chaetiger 3 and end of chaetiger 5 (
Fig. 4
B). Prostomium with three antennae; median antenna inserted medially on prostomium, lateral antennae on anterior margin. Tentacular cirri two pairs. Median antenna reaching c. chaetiger 20. Lateral antennae, and dorsal tentacular cirri 1/3–1/2 as long as median antenna; first dorsal cirri as long as median antenna; ventral tentacular cirri and second dorsal cirri c. half as long as dorsal tentacular cirri. Dorsal cirri from chaetiger 1 with following alternation in direction, where D=cirri pointing down and U=cirri pointing up: U DDU DU DDU followed by eight DU-groups, 4 DDUUgroups, and up to 28 DDU-groups. From chaetiger 3 dorsal cirri alternating in length; short cirri as long as c. 4/5 of body width, long cirri as long as c. 1.2 times body width. Cirrophores on tentacular cirri and all dorsal cirri. Cirrophores alternating in length along the body; cirrophores on short cirri c. half as long as cirrophores on long cirri. Cirrostyles alternating in length in anterior and posterior chaetigers, but not in median chaetigers; cirrostyles on short cirri c. 1.5 times as long as cirrostyles on long cirri in anterior chaetigers, equally long in median chaetigers, and 2/3 as long in posterior chaetigers. Cirrophores on short cirri equal or slightly longer than parapodial lobes, cirrophores on long cirri longer than parapodial lobes. Cirrophores shorter than cirrostyles on short cirri, cirrophores longer than cirrostyles on anterior long cirri, equal in length in mid-body long cirri, and shorter in posterior long cirri (
Fig. 4
A). Parapodial lobes of medium size, rounded. Aciculae
2–3 in
anterior chaetigers, 1or
2 in
median and posterior chaetigers. Chaetal fascicle with 10–12 compounds in anterior chaetigers,
6–9 in
median and posterior. Compound chaetae with small distal tooth (
Fig. 5
F) and serrated blade. Single thin bayonet chaetae (
Fig. 5
G), beginning on chaetiger 20–31. Pharynx with sinuation mostly anterior to proventricle (
Fig. 4
A). Trepan in chaetiger 2–4, with 33–45 equal, or nearly equal, teeth (
Fig. 5
H). Basal ring present, infradental spines present. Proventricle as long as 4–6 segments, in chaetiger 10–20 (
Fig. 4
A) with 30–37 rows of muscle cells. Anal cirri as long as 1.5–3 times body width.
Reproduction.
Probably with schizogamy. Three specimens have pink eggs from about chaetiger 40, one of them with a newly regenerating posterior end behind chaetiger 63 (
Fig. 4
C).
Habitat.
Among
Cladocera caespitosa
blocks,
Padina
and other algae, and in coralligene,
15–
30 m
.
Distribution.
Mediterranean, from Chafarinas Islands in
Morocco
, Istria in
Croatia
, and Banyuls-sur-Mer in
France
.
Intraspecific genetic variation.
A single haplotype in the four specimens from Banyuls-sur-mer, and four haplotypes in the four specimens from
Croatia
were found in COI. The haplotypes from
Croatia
cluster together but are separated from each other with 1–4 mutational steps (uncorrected p = 0.41±0.16%). This group is in turn separated from the single Banyuls-sur-Mer haplotype with a minimum of six mutational steps (uncorrected p=1.11±0.18%). As for 16SrDNA, we found two haplotypes in the two Banyuls-sur-Mer specimens, and a single haplotype in the four Croatian specimens. The two Banyuls-sur-Mer haplotypes are separated from each other by a single mutational step, and the Croatian haplotype is separated by a single mutational step from the closest Banyuls-sur-Mer haplotype.
Remarks.
Myrianida longoprimicirrata
is a poorly known member of the genus, never recorded after the original description. The relationship between cirrophores and cirrostyles was not possible to assess in the original description or from the
types
. In the present material, the cirrophores are longer than cirrostyles on long anterior dorsal cirri and, then gradually become shorter towards the posterior end where they are shorter than cirrostyles. The only
Myrianida
which have cirrophores longer than cirrostyles on the long cirri are
M. dentalia
(
Imajima, 1966
)
,
M. langerhansi
,
M. pentadentata
(
Imajima, 1966
)
,
M. multidenticulata
(
Westheide, 1974
)
,
M. pulchella
(
Day, 1953
)
, and
M. rangiroaensis
(
Imajima, 1966
)
. We lack molecular data for the latter three species, but among the sequenced species
M. longoprimicirrata
is most closely related to
M. pentadentata
. Morphologically
M. longoprimicirrata
may be separated from all the aforementioned species by the 33–45 equal, or nearly equal, teeth, on the trepan, compared to a varied number and arrangement of distinctly unequal teeth in all species except
M. pentadentata
which has five equal teeth.