Review of Amaeana Hartman, 1959 (Annelida, Terebelliformia, Polycirridae), with descriptions of seven new species
Author
Nogueira, João Miguel De Matos
Author
Carrerette, Orlemir
Author
Hutchings, Pat
text
Zootaxa
2015
3994
1
1
52
journal article
10.11646/zootaxa.3994.1.1
1334b429-62a4-4505-9e05-d68b39058e5c
1175-5326
289137
093B124E-58AE-4303-8C07-2D7B27E6AC38
Amaeana hsiehae
sp. nov.
Figures 5
,
6
,
7
and
8
Material examined.
Holotype
(
ASIZW
0000935): complete specimen, in good state of preservation; slides: notochaetae, segment 6; neurochaetae, segment 21; neurochaetae, posterior segment.
Paratypes
:
ASIZW
0000936: incomplete, in good state of preservation,
13 mm
long,
1.2 mm
wide;
ASIZW
0000937: incomplete, in good state of preservation,
13 mm
long,
1 mm
wide;
ASIZW
0000938: complete, in good state of preservation, but very fragile and full of oocytes,
23 mm
long, ~
4 mm
wide; AM W.47362 complete, in good state of preservation,
11 mm
long,
0.8 mm
wide, mounted on SEM stub; AM W.47363: complete, in good state of preservation, but very fragile and full of oocytes,
31 mm
long, ~
3.5 mm
wide; AM W.47364: complete (in two pieces), in good state of preservation, but very fragile and full of oocytes,
34 mm
long, ~
3 mm
wide. All
type
material collected from—Wuijang Estuary, Kinmen Island,
Taiwan
,
24°25’44.04’’N
,
118°18’53.80’’E
, small tidal creek, enriched with organic matters, which flows intermittently, muddy substrate (> 60 %) plus debris of oyster shells; intertidal.
Type
locality.
Taiwan
, Kinmen Island, Wuijang Estuary,
24°25’44.04’’N
,
118°18’53.80’’E
, intertidal.
Description.
Holotype
complete specimen,
17 mm
long,
1 mm
wide at segment 8, maximum width of body;
paratypes
up to
34 mm
long and ~
3.5 mm
wide (see above).
Prostomium at base of upper lip, both basal and distal parts developed, basal part as thickened crest, distal part with large flaring lobes, mid-dorsal process not clearly delineated; prostomium covering segment 1 laterally and terminating laterally to lower lip, near mouth (
Figs 5
A–K, M, P–Q; 7A–I). Buccal tentacles of three
types
, short ones thin, uniformly cylindrical, except for expanded sphaerical to elliptical tip; intermediate tentacles thin, uniformly cylindrical, also expanded at tip; long tentacles progressively widening at tip, towards clearly marked subdistal cylindrical inflation, with short and pointed tip (
Figs 5
A–K, M, P–Q; 7A–I); all
types
with ciliated groove only at tips.
Peristomium restricted to lips, upper lip longer than broad, with straight lateral margins, almost rectangular; lower lip short, rounded to rectangular, button-like (
Figs 5
A–K, M, P–Q; 7A–D, F–G, I).
Body progressively broader on segments 3–7, of relatively uniform width until segment 10, tapered on segments 11–18, then of relatively uniform width, with cylindrical segments through mid- and posterior body, tapering near pygidium (
Figs 5
A–Q; 7A–I; 8H–I); achaetous gap between termination of notopodia and beginning of neuropodia, corresponding to segments 13–19, with poorly marked segmentation and fragile, with thin body wall dorsally, about same size or slightly longer than region with notopodia (
Figs 5
A–E, G–H, N, P–Q; 7A–B).
Segments biannulated, segment 1 short, visible dorsal and ventrally; segment 2 narrower and shorter than following segments, with relatively large, pentagonal mid-ventral shield at beginning of mid-ventral groove, extending anteriorly through segment 1 until near ventral edge of lower lip, about same length as that of segment 3 and slightly broader (
Figs 5
A–K, M, P–Q; 7A–I). Ventrum highly glandular, covered with small papillae, arranged in paired ventro-lateral pads on segments 2–12; papillae about same size throughout and slightly more numerous on anterior segments; from after termination of notopodia, paired longitudinal crests bordering mid-ventral groove through posterior body (
Figs 5
A–Q; 7A–I; 8A, G–J).
Notopodia extending through 10 segments, until segment 12; elongate, cylindrical notopodia, with equal sized lobes and elongate and distally blunt tips (
Figs 5
A–E, G–I, K, M, P–Q; 7A–I; 8A–C). Pinnate chaetae in both rows, those from posterior row pinnate only on distal half (
Figs 6
A–B; 8A–F).
Neuropodia present from segment 20, laterally to mid-ventral groove, on outer margins of longitudinal crests. Neurochaetae as 2–3 relatively stout, distally tapered spines, slightly expanded subdistally, with short oblique tip; only tips protruding (
Figs 5
A–D, N–P; 6C–E; 8G–L).
Nephridial and genital papillae anterior to bases of all notopodia, those of segments 6–10 larger in sexually mature specimens, at least on females (
Figs 5
P–Q; 7A–F, H–I); several specimens with additional pair of papillae on segment 13. Pygidium crenulate, with slightly larger ventral papilla (
Figs 5
A–D, L, O–P; 8 H–I, M).
Remarks.
Amaeana hsiehae
sp. nov.
is unique among the species of this genus in having pinnate notochaetae in both rows. The only other species of
Amaeana
with conspicuously pinnate chaetae visible under light microscopy is
A. occidentalis
, however this latter species only has these chaetae in posterior row of notochaetae, those from anterior row being acicular (see below).
Besides the pinnate notochaetae,
Amaeana hsiehae
sp. nov.
is also characterised by having 10 pairs of notopodia, achaetous gap of 7 segments between termination of notopodia and beginning of neuropodia, and neuropodia bearing 2–3 spines. In addition, the shape of the upper lip of
A. hsiehae
sp. nov.
is unique among species of this genus, nearly rectangular, higher than broad and with almost straight lateral margins.
FIGURE 5.
Amaeana hsiehae
sp. nov.
, ASIZW0000935. A–D, entire worm, right ventro-lateral, right lateral, left lateral and left dorso-lateral views, respectively; arrows point to beginning of neuropodia; E–F, progressively closer views of the anterior end, ventral view; G–H, thorax, right and left lateral views, respectively; I–K, close ups of the anterior end, left dorso-lateral, ventral and right lateral views, respectively; L, posterior end, left dorso-lateral view; M, close up of the anterior end, left dorsolateral view; N, abdominal segments; arrows point to neuropodia; O, posterior end, right ventro-lateral view. Paratype AM W.47363: P, entire worm, left lateral view (anteriorly); Q, thorax, left lateral view. Numbers refer to segments; ll = lower lip, P = basal part of prostomium; ul = upper lip. Scale bars: A = 0.6 mm; B–D, H = 0.5 mm; E, G = 0.4 mm; F, I–L, N = 0.2 mm; M, O = 0.15 mm; P = 1.5 mm; Q = 1 mm.
FIGURE 6.
Amaeana hsiehae
sp. nov.
, holotype ASIZW0000935. A–B, progressively closer views of the notochaetae of segment 6; C–E, neurochaetae, segments 21 and two consecutive posterior ones, respectively. Scale bars: A = 30 µm; B = 15 µm; C–E = 7 µm.
Five other species of
Amaeana
share with
A. hsiehae
sp. nov.
the presence of 10 pairs of notopodia,
A. apheles
,
A. angulus
sp
.
nov
.
,
A. trilobata
,
A. ellobophora
sp. nov.
and
A. crassispinulata
sp. nov.
(
Table 1
). Members of
A. apheles
differ from
A. hsiehae
sp. nov.
in having an almost circular upper lip, a larger achaetous gap between termination of neuropodia and beginning of neuropodia, representing 9–10 segments, and stout, distally sharp spines, while in
A. hsiehae
sp. nov.
, in addition to what has been said above, the spines are distally tapered, but not as sharp as those of
A. apheles
(compare
Figs 6
C–E and 9K). Members of
A. angulus
sp. nov
.
differ from those of
A. hsiehae
sp. nov.
in having a circular upper lip, slightly larger achaetous gap between termination of notopodia and beginning of neuropodia, extending for 8 segments, and neuropodia with 4–5 spines each.
Amaeana trilobata
has a shorter achaetous gap between termination of notopodia and beginning of neuropodia, 3 segments only, lacks modified buccal tentacles, has an elliptical upper lip and each neuropodium bears 7–8 spines.
Amaeana ellobophora
sp. nov.
, also has a shorter achaetous gap between termination of notopodia and beginning of neuropodia, 5 segments, a nearly circular upper lip, and each neuropodium bears 8–11 spines. Finally, in
A. crassispinulata
sp. nov.
, the number of achaetous segments between termination of notopodia and beginning of neuropodia resembles that of
A. hsiehae
sp. nov
.
, 8 segments, but each neuropodium has a single spine, and these are basally wider and distally truncate, as described below.
Etymology.
We dedicate this species to Dr Hwey-Lian Hsieh, from Academia Sinica,
Taiwan
, who collected the material and invited
PH
to identify the worms.