Classification and Morphological Variations of the Japanese Species of Lumbrinerides (Annelida: Lumbrineridae)
Author
Miura, Tomoyuki
text
Species Diversity
2017
Auckland, N. Z.
2017-05-25
22
1
7
27
http://dx.doi.org/10.12782/sd.22_7
journal article
4218
10.12782/sd.22_7
5ba59b53-1409-4f01-ab58-a5bf8a2c3c2e
2189-7301
4583750
DC28F09A-556E-4783-BC6C-5A69C50D359F
Lumbrinerides kristiani
sp. nov.
(
Figs 13
,
14
)
Material examined.
Holotype
: NSMT-Pol H-610,
Seisui-Maru Cruise
1984-R-07,
Station
402 B (intact
female
),
Irago Strait,
34°20.2′N
,
136°60.0′E
,
39.2 m
,
13 September 1984
;
3 paratypes
: NSMT-Pol P-611 (one female, two immature), same site as
holotype
; seven
paratypes
: NSMT-Pol P-611 (one female, six immature), Station 402 A, same site as
holotype
; three
paratypes
: NSMT-Pol P-612 (two females, one immature), Station 502 A, Ago Inlet, 60.0 m,
16 September 1984
.
Non-type material.
(
EK
A) Seisui-Maru Cruise 1984-R-07, Stations, 201 A (including two immature); 301 A (one immature, one juvenile) and 301 B (three immature, one juvenile); 302 A (one immature, one juvenile) and 302 B (one immature); 402 A (one juvenile); 403 A (two immature, one juvenile) and 403 B (one juvenile); 501 B (one male); 502 B (two immature); 701 B (one immature). (
KII
A) Tansei-Maru Cruise KT-84-12, Station 11-2 (one immature); Station 12-1 (one immature). (
BUNG
) Tansei-Maru Cruise KT-84-12, Stations 31 (three immature); 33 (one immature).
Description.
The
holotype
is an intact female measuring
20 mm
long by
0.47 mm
wide with 175 chaetigers.
Prostomium 1.94 times longer than wide. Peristomium comprising two apodous rings (
Fig. 13A
). First five parapodia reduced (
Fig. 13D, E
). Postchaetal lobes rounded with a very short projection on central outer edges between chaetigers 5–8 (
Fig. 13E, F
). Projection becoming larger, fused with basal parts, being digitiform to conical from chaetiger 9 (
Fig. 13
G–J). Limbate chaetae broadly limbate at least on first several parapodia, becoming narrower posteriorly. Limbate chaetae numbering two per parapodium on chaetigers 1–6, three on chaetigers 7–22, two on chaetigers 23–87 and one on chaetigers 88–126 (
Fig. 14
). Far posterior parapodia on chaetigers 127–173 lacking limbate chaetae (
Fig. 13J
). A single limbate chaeta on each parapodium on last chaetiger in
holotype
(
Fig. 14
). Simple bidentate hooded hooks beginning on chaetiger 1, two per parapodium on chaetigers 1–6, one on chaetigers 7–22, two on chaetigers 23–26, three (sometimes two or four) on chaetigers 27–174 and none on chaetiger
175 in
holotype
(
Fig. 14
). Mandibles with four concentric lines on anterior flared end in
holotype
, but sometimes eight in larger specimens of
0.66 mm
width (
Fig. 13C
). Maxillae I with a single well-defined accessory tooth (
Fig. 13B
). Maxillae II with three blunt teeth on both plates. Maxillae III lacks defined teeth. Maxillae IV comprising long oval plates without teeth.
Biological notes.
The spawning season of this species is thought to be in summer since a collection in
September 1984
(
EK
A) included matured specimens with fully developed gametes
.
Variations.
Accessory teeth on maxillae I usually numbered one (rarely two) on one or both sides. In the case of two accessory teeth on each maxilla I, such were intermeshed with only one being well developed whereas the remaining tooth could be recognized only from their internal cavities found in the medulla of maxillae I. The prostomium length to width proportion varied from 1.3 to 2.6. First simple hooks always occurred at the first parapodium, the number of anterior reduced parapodia varying between four and six. Well developed parapodia with prolonged postchaetal lobes began from chaetigers 7–11 (chiefly 9–10).
Remarks.
This species differs from other Japanese species in having a combination of character states, such as having only one accessory tooth on maxillae I in general, a small number of anterior reduced parapodia and simple hooks starting on chaetiger 1.
Lumbrinerides dayi
differs from the new species in having ten anterior reduced parapodia instead of four to six. One of the specimens identified as
L. dayi
by
Imajima (1985)
may in fact be referred to this new species, due to having six anterior reduced parapodia, a single accessory tooth on maxillae I and hooks starting on anterior parapodia (parapodium
4 in
an Imajima’s damaged specimen).
Fig. 14. Chaetal distribution pattern in
Lumbrinerides kristiani
sp. nov.
, holotype (NSMT-Pol H-610), one of paratypes (NSMT-Pol P-611: BW 0.66 mm) and non-type materials. Numbers of hooks (closed circles) and limbate chaetae (open circles) per parapodium plotted on each parapodium from first to last chaetigers of fragmented specimens.
Etymology.
The new species is named for Dr Kristian Fauchald, Research Zoologist at the Smithsonian Institution, who encouraged me at the beginning of my scientific life and passed away
4 April 2015
.
Distribution.
Off Hamana Lake (
40–41 m
), off Tawara (
40–61 m
), Irago Strait (
39–80 m
), Ago Bay (
39–60 m
), off Kumano River (
39 m
), off Susami, Kii Channel (
73–101 m
), off Tsukumi, Bungo Channel (
72–76 m
), on sandy substrates, Pacific coast of
Japan
; East
China
Sea (
40 m
).