Revision of Leocrates Kinberg, 1866 and Leocratides Ehlers, 1908 (Annelida, Errantia, Hesionidae)
Author
Salazar-Vallejo, Sergio I.
text
Zootaxa
2020
2020-02-18
4739
1
1
114
journal article
23993
10.11646/zootaxa.4739.1.1
d3e60fb6-636b-4e03-b55a-0e910f9a468e
1175-5326
3672547
544B9C82-BF33-4EA1-9411-E1A307137466
Paradalhousia papillosa
(
Monro, 1926
)
reinst., n. comb.
Figure 51
Leocrates papillosus
Monro, 1926: 313
;
Leocrates giardi
:
Pettibone 1970: 219–221
,
Fig. 17–19
(
partim
, only figure 19,
non
Gravier, 1900
).
Type
material
.
China
Sea
. Two
syntypes
(
BMNH
1926.4.30.130–131), Macclesfield Bank (
16°00’ N
,
114°30’ E
), no further data [very damaged after chaetal fracture and removal of many parapodia; description based upon both of them]
.
Additional material
.
Sibuyan Sea
. One specimen (
MNHN
Musorstom 3-137),
Philippines
, Sta. 137 (
12°03’ N
,
122°06’ E
),
56 m
,
6 Jun. 1985
[
8.5 mm
long,
1 mm
wide].
Description
.
Syntypes
(BMNH 1926.4.30.130–131) complete, smaller
syntype
better preserved, slightly bent laterally (
Fig. 51A
). Body
12 mm
long,
2 mm
wide, 16 chaetigers; left parapodia of chaetigers 8–10 and, right parapodia of chaetigers 6, 7, 9 and 12 previously removed. Larger
syntype
slightly bent laterally and ventrally. Body
13 mm
long,
2 mm
wide, 16 chaetigers; left parapodia of chaetigers 8–9, and right parapodia of chaetigers 2, 3, 9–11 previously removed; right parapodia of chaetiger 8 removed for observing parapodial features (kept in container with
syntypes
). Pharynx with a longitudinal, and a transverse previously made dissections. Body pale, eyes and peristomial middorsal tubercle brownish; most cirri missing.
Prostomium longer than wide, wider anteriorly (
Fig. 51B
). Lateral antennae with ceratophores distinct, without tips in smaller
syntype
, almost as long as prostomium, longer than palps in larger
syntype
; palpophores slightly longer than palpostyles. Median antenna tiny, probably eroded, tapered, inserted centrally between eyes.
Eyes brownish, round; anterior eyes emarginate anteriorly, slightly larger and slightly more distant to each other than posterior round ones; in lateral view anterior and posterior eyes distinct (
Fig. 51B
).
Nuchal organs lobes U-shaped, parallel to convergent, prostomial posterior projections pale; middle furrow deep. Lateral ciliated bands visible dorsally. Tentacular cirri broken, one ventral incomplete one reaches chaetiger 1. Lateral cushions swollen, projected, entire along body, longitudinal striae visible.
Pharynx fully everted in smaller
syntype
(
Fig. 51C
); anterior margin with 20 small, oval denticles, middorsal and midventral areas bare. Upper and lower jaws single, tiny, barely pigmented (an irregular fleshy projection ahead of dorsal jaw).
Chaetigers 1–3 without notochaetae; notochaetae present along chaetigers 4–16, about 50 per bundle, delicate, many broken; if entire, approaching neurochaetal tips, subdistal denticles mostly eroded, visible in a few chaetae, fine. Notacicular and neuracicular lobes tapered, pointed (
Fig 51D
); notacicular lobes twice longer than wide, neuracicular ones as long as wide. Neurochaetae broken in most chaetigers, about 20 per bundle, blades bidentate, 11–13 times longer than wide, guards approaching subdistal tooth (
Fig. 51D
, inset).
Posterior region tapered. Prepygidial segment without cirri, dorsal cirrophores twice wider than ventral ones. Pygidium with anus terminal, anal cirri missing.
Oocytes not seen.
Variation
. A non-type, better-preserved small specimen (
MNHN
Musorstom 3-137) has about 30 neurochaeta per bundle, and their blades are 4–16 times longer than wide. The illustration by
Pettibone (1970
,
Fig. 19e
) based upon the study of the
syntypes
indicates they were 5–11 times longer than wide.
Remarks
.
Paradalhousia papillosa
(
Monro, 1926
)
n. comb.
is reinstated because it was regarded as a junior synonym of
Leocrates giardi
Gravier, 1900
by
Pettibone (1970: 219)
, but they belong to different genera. Further,
P. papillosa
is newly combined into
Paradalhousia
because it has U-shaped nuchal organs, single upper and lower jaws, and pale neurochaetae. On the other hand,
P. papillosa
differs from
P. oculata
(
Treadwell, 1906
)
especially in the number of neurochaetae, and in the orientation of their distal teeth. In
P. papillosa
there are about 20(–30) neurochaetae per bundle, and their distal teeth are straight, whereas in
P. oculata
there are about 50 neurochaetae, and their distal teeth are falcate.
FIGURE 51
.
Paradalhousia papillosa
(
Monro, 1926
)
new combination
, reinstated, smaller syntype (BMNH 1926.4.30.130– 131). A. Dorsal view. B. Anterior end, dorsal view, MGS. C. Same, ventral view. D. Larger syntype, chaetiger 8, right parapodium, anterior view, MGS (insets: notacicular lobe, remaining neurochaetal blades). Scale bars: A: 0.9 mm, B: 0.3 mm, C: 0.4 mm, D: 0.2 mm.
Monro (1926)
included this species from the Macclesfield Bank, South
China
Sea, as a part of the third contribution from the HMS Alert Expedition samples (
Monro, 1926
). However, that voyage did not include the
China
Sea, as can be confirmed elsewhere (
Coppinger 1884
,
Günther 1884
). Consequently, the collector attribution, or field data are undefined, but the locality is regarded as precise, albeit the depth was not indicated in the third contribution. For the first two contributions (
Monro 1924a
, b), other species were recorded from the same site from stations made at
54–65 m
,
54–81 m
,
54–90 m
,
90–
108 m
. However, sampling was made by two vessels: HMS
Rambler
in early 1888, and HM Surveying-Vessel
Penguin
in early 1892, and all specimens were deposited in The Natural History Museum, London (
Anonymous 1895
). The corals collected during the first survey were reported by
Bassett-Smith (1890)
, who included the description of five new species, and also included a map with depth data and collecting stations.
Distribution
. Macclesfield Bank (E Paracel Islands) to the
Philippine Islands
, in mixed bottoms,
54–108 m
depth.