On the diversity of Terebellides (Annelida, Trichobranchidae) in West Africa, seven new species and the redescription of T. africana Augener, 1918 stat. prom.
Author
Parapar, Julio
Departamento de Bioloxía, Universidade da Coruña, E- 15008 A Coruña, Galicia, Spain
julio.parapar@udc.es
Author
Martin, Daniel
Centre d’Estudis Avançats de Blanes, CEAB-CSIC, Blanes, Catalonia, Spain
dani@ceab.csic.es
Author
Moreira, Juan
Departamento de Biología (Zoología), Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, E- 28049 Madrid,
juan.moreira@uam.es
text
Zootaxa
2020
2020-05-06
4771
1
1
61
journal article
22348
10.11646/zootaxa.4771.1.1
64e78db8-9b9c-477a-bbc5-aff043ad9b51
1175-5326
3798452
A46FAF72-6F95-4DA3-A41D-FE770D6EDF1F
Terebellides ramili
sp. nov.
Figures 11D
,
28B
,
33
,
34
,
37
; Tables 1, 2
urn:lsid:zoobank.org:act:
97DCCE83-A2BC-48EF-B84A-BB20123827AF
Material examined. Type material.
Four specimens:
holotype
(
MNCN16.01
/18615); three
paratypes
(
MNCN 16.01
/18613, 16.01/18614 and 16.01/18616).
Non-type material
. One specimen (NHMD-231438, Table 1)
.
Diagnosis
. Body small/medium sized (
18.5 mm
in length); TC1–5 ventrally whitish. Branchial anterior lobe absent; posterior ventral lobes thinner than dorsal ones, with terminal filament and directly emerging from branchial stem. TC1 notopodia and notochaetae as long as following ones. Thoracic neurochaetae with
rostrum/capitium
length about 1/1, and
capitium
with a first row of 5−6 small teeth followed by similar sized ones.
Description based on
holotype
Measurements and general body features. Complete specimen,
18.5 mm
long and
1.5 mm
wide; female with oocytes in body cavity (
Fig. 28B
,
33
A−B). Body tapering posteriorly with segments increasingly shorter and crowded towards pygidium. Prostomium compact; short tentacular membrane surrounding mouth, devoid of buccal tentacles. SGI as an expanded structure below tentacular membrane (
Fig. 33A
). Lateral lappets on SGIII–VII (TC1–5), larger in SGIII–IV (
Fig. 33B
).
Branchiae. Branchiae arising as single structure from SGIII, with a single stalked mid-dorsal branch (
Fig. 28B
) having one pair of dorsal (upper), non-fused lobes and one pair of shorter ventral (lower) lobes, neither fused together nor to dorsal ones, with terminal filament (
Fig. 28B
,
33
A−B). Anterior projection of dorsal lobes (lobe 5) absent. Both sides of branchial lamellae with cilia; rows and/or tufts or papillae not seen.
Thorax. Eighteen pairs of notopodia (SGIII–XX), with those of TC1 as long as subsequent ones. Neuropodia as sessile pinnules, from TC6 (SGVIII) to pygidium, with uncini in single rows starting from TC7 (SGIX) throughout. First neuropodia (TC6) with 4–5 sharply bent, acute-tipped, geniculate chaetae (
Fig. 34A
) showing minute teeth forming a
capitium
. From TC7, neuropodia with up to 6–10 uncini per torus in one row, with long shafted denticulate hooks,
rostrum
about same length as
capitium
, with 8–10 small teeth above main fang, surmounted by two rows of several teeth of same size (
Fig. 34
B–D).
Abdomen. Thirty-one neuropodia as erect pinnules, with about 25−30 uncini per torus having four teeth above main fang surmounted by an upper crest of 4–5 teeth and a variable number of smaller teeth (
Fig. 34
E–F).
Other body features. Pairs of nephridial papillae both at TC1; dorsal paired nephridial openings in anterior thoracic notopodia not seen. Pygidium blunt, as funnel-like depression. Five anterior thoracic chaetigers (TC1−5) ventro-laterally whitish (
Fig. 33A
); last two (TC4–5) more pigmented.
Methyl green staining pattern. Anterior
CH
1 to
CH
3 solid;
CH
4 to
CH
12 striped; being
CH
4 and
CH
5 much more marked than previous ones, and
CH
12 faded; J-shaped glandular region slightly marked lateral to
CH
2 and
CH
3; near pattern 5 of
Schüller & Hutchings (2010)
(
Fig. 37
).
Variability
. Body 6.0 mm long in the only complete (and probably immature)
paratype
(MNCN16.01/18613). Specimen NHMD-231438 (
Fig. 33C
), collected during the
Galathea
expedition
and originally identified as
T. stroemii
by
Kirkegaard (1959)
, has been identified here as
T
. af.
ramili
. It is a 22-mm long female with oocytes that was collected nearby the type location and at similar depths (Table 1). However, its identity cannot be fully confirmed as colouration of TC4–TC5 is different than others being more widely distributed in TC4 and much less in TC5 (
Fig. 33C
). Moreover, this specimen bears shorter branchial ventral lobes than in
T. ramili
sp. nov.
and lacks terminal filament.
Type
locality.
Off
Congo
;
190 m
depth
(Table 1)
.
Distribution and bathymetry.
Off
Congo
and
Namibia
;
190−537 m
depth (
Fig. 11D
; Table 1).
Etymology.
The species is named after Dr. Francisco Ramil (Universidade de Vigo,
Spain
), for his numerous contributions to the taxonomy of marine invertebrates, especially Cnidarians, in many world seas but specifically in the Iberian Peninsula,
Antarctica
and the Atlantic African littoral.
FIGURE 33.
(
A–B)
Terebellides ramili
sp. nov.
Stereomicroscope images of holotype MNCN 16.01/186013.
(A)
full specimen, right lateral view;
(B)
anterior end, left lateral view.
Terebellides
af.
ramili
(NHMD-231438):
(C)
anterior end, right lateral view. Abbreviations: bldl—branchial left dorsal lobe; blvl—branchial left ventral lobe; brdl—branchial right dorsal lobe; brvl—branchial right ventral lobe; bvltf—branchial ventral lobe terminal filament; gc—geniculate chaetae; loli—lower lip; ooc—oocytes; SG—segment; TC—thoracic chaetiger; tm—tentacular membrane.
FIGURE 34.
Terebellides ramili
sp. nov.
SEM micrographs of the paratype MNCN 16.01/18614.
(A)
TC6 geniculate chaetae;
(B–D)
thoracic uncini in latero-frontal, lateral and upper view;
(E–F)
abdominal uncini, fronto-lateral view. Circle in (D) showing number of teeth on
capitium
. Abbreviations: cap—
capitium
; ros—
rostrum
.
Remarks
. The conspicuous white colouration of
T. ramili
sp. nov.
resembles that of the boreal
Terebellides gracilis
Malm, 1874
, recently reported from
Iceland
by
Parapar
et al
. (2011)
and the Adriatic Sea by
Parapar
et al
. (2013)
. The
type
material redescribed by
Parapar
et al
. (2011)
shows a homogeneous colour pattern between TC1 and TC4, while in
T. ramili
sp. nov.
it appears from TC1 to TC5 being even more conspicuous in TC4 and TC5. Furthermore, TC1 notopodia and notochaetae in the Mediterranean specimens of
T. gracilis
are smaller than in other chaetigers (similar throughout or slightly larger in
T. ramili
sp. nov.
) and the thoracic uncini show large anterior teeth in the
capitium
(
Parapar
et al
., 2011
:
Fig. 10C
). These teeth are closer to
Type
1, as it happens in
T. longiseta
sp. nov.
and
T. kirkegaardi
sp. nov.
, or
Type
2, as in
T. fauveli
sp. nov.
, and different to the
Type
4 present in
T. ramili
sp. nov.
Moreover,
T. ramili
sp. nov.
also differs from the three aforementioned species in the branchial shape, size of TC1 and ventral colour pattern (see above).