Two new species of Marphysa Quatrefages, 1865 (Polychaeta: Eunicida: Eunicidae) from northern coast of China and redescription for Marphysa orientalis Treadwell, 1936
Author
Liu, Yubin
Author
Hutchings, Pat
Author
Kupriyanova, Elena
text
Zootaxa
2018
2018-02-01
4377
2
191
215
journal article
30866
10.11646/zootaxa.4377.2.3
5cb64c13-76bb-45f3-9a12-c2413c64c537
1175-5326
1163893
B1EFF160-FD26-4A18-A274-4E605EEEEE2F
Marphysa bulla
n. sp.
Figures 2
,
3
Material examined.
Holotype
:
AM
W.49124
; paratypes: AM W.49125, width at chaetiger 10, 6.75 mm, length to chaetiger 10, 8.8 mm, complete with 321 chaetigers, gravid; AM W.49126, width at chaetiger 10, 6.25 mm, length to chaetiger 10, 10.35 mm, complete with 309 chaetigers; AM W.49127, width at chaetiger 10, 7.9 mm, length to chaetiger 10, 14.05 mm, complete with 385 chaetigers; MBMCAS285106, width at chaetiger 10, 7.05 mm, length to chaetiger 10, 11.3 mm, complete with 342 chaetigers. All specimens were collected intertidally from the Rongcheng coast (37.16°N, 122.41°E) in 2014, see
Fig. 1
.
Description
. Holotype complete, with 363 chaetigers, body iridescent. Animal reddish-brown when alive, preserved specimens beige. Maximum width at chaetiger 10, 7.9 mm, excluding parapodia; length to chaetiger 10, 7.9 mm.
Prostomium shorter than peristomium, margins dorsally flattened with conspicuous deep median sulcus (
Fig. 2A
). Eyes absent. Medial antenna longest and thickest prostomial appendage, inserted more posteriorly than lateral antennae. Antennophores short, ring-shaped; antennal style tapering, wrinkled, longest antennal style reaching to chaetiger 3. Palps wrinkled, shorter than antennae. Antennae 1.3 times length of palps. Peristomial rings complete, well demarcated (
Fig. 2B
). Mandibles with calcareous plates longer than sclerotized matrix (
Fig. 3F
), same length as maxillae I plus carriers. Maxillary apparatus with four pairs and one single maxilla; MF= 1+1, 4+4, 6+0, 3+6, 1+1 (
Figs 2D
,
3E
). Maxillary carriers 2.5 times shorter than MI, with triangular anterior region tapering posteriorly with pair of basal triangular wings. Maxillae I, forceps -like with swollen base with deep vertical falcal arch, with curved blunt tips without attachment lamellae, heavily chitinised, dark brown. Maxillae II, with four recurved triangular teeth pointing downwards, dark brown, ligament between MI and MII dark, rectangular. Maxillae III, short, curved, forming distal arc; with five blunt triangular teeth only in centre of posterior edge of maxillae, no attachment lamella, pale brown. Maxillae IV, with three and five teeth respectively, all smooth, similar sized triangular shaped, pale brown. Maxillae V, rectangular, single recurved tooth, pale cream (
Fig. 3E
).
Parapodia varying along body. Anterior parapodia with prechaetal lobe shorter than chaetal lobe, postchaetal lobe also shorter than acicular lobe, but longer than prechaetal, all lobes rectangular with rounded margins. Median parapodia with small rectangular prechaetal lobe and post chaetal lobes, acicular lobe largest increasing in size from anterior to median parapodia, initially rectangular, and becoming more digitally shaped with rounded margins progressively from median parapodia onwards. Posterior parapodia with very poorly developed pre- and postacicular lobes decreasing in size from median to posterior parapodia. Dorsal cirrus shorter than chaetal lobes, elongate tapering, similar length along entire body. Ventral cirrus anteriorly shorter than chaetal lobes and dorsal cirrus, inflated leaf-shaped with small blunt tip, becoming increasingly more inflated along body and rectangular in shape. Ventral cirri with small globular papillae inserted on anterior margin close to acicular lobe, progressively base of ventral cirrus becoming more globular and rounded, on posterior parapodia base becoming more leafshaped with rounded margins (
Fig. 2C
).
Branchiae pectinate, beginning from chaetiger 36 and continuing to chaetiger 328. In anterior branchiae number of branchial filaments 1–2, maximum number of branchial filaments 5 (
Fig. 2E
) in median parapodia. Length of branchial filaments where best developed up to 3 times length of dorsal cirrus. Aciculae black with paler tips, ranging from 2–5 per parapodium (para 10 with 5; para 75 with 4; para 140 with 3; para 205 with 2; para 271 with 2; para 335 with 3). Subacicular hooks transparent/pale yellow, unidentate, present from mid-body parapodia (chaetiger 71) onwards, up to 3 per parapodium.
Neurochaetae in two distinct bundles, supra-acicular with limbate capillaries and pectinate chaetae, subacicular with compound spinigers and subacicular hooks. Compound spinigers with blades of two lengths within sub-acicular fascicle, blades of longer ones twice as long as length of shorter ones, with more extended smooth tips, all with smooth blades (
Fig. 3A
). Number of compound spinigers within a parapodium 18–33 (para 10 with 9; para 75 with 15; para 140 with 16; para 205 with 8; para 254 with 9). Compound falcigers absent. Pectinate chaetae present along entire body (
Fig. 2J–L
), but restricted to supra-acicular fascicle. Number of pectinate chaetae within a parapodium 2–15, with numbers increasing along body and number of types of chaetae also varying along body. Chaetiger 4 with one type, thin symmetrical isodont with about 13 or 17 teeth (
Fig. 3
Ba). Chaetiger 75 with one type, thin symmetrical isodont with either 13 or 17 teeth. Chaetiger 135 with three types: thin asymmetrical isodont with numerous teeth (~30–40) (
Fig. 3
Bc), thin symmetrical isodont with 14 teeth (
Fig. 3
Ba, 3Da) and thick asymmetrical anodont with 4 or 5 teeth (
Fig. 3
Bb, Cb). Chaetiger 313 with three types: thin asymmetrical isodont with varying numbers of teeth (
Fig. 3
Cc), thin asymmetrical isodont with varying numbers of teeth (
Fig. 3
Ca) and thick asymmetrical anodont with 3 or 4 teeth (
Fig. 3
Cb).
Six–21 simple capillary chaetae per parapodium arranged in 2 tiers of length present in supra-acicular fascicle, numbers of capillary chaetae similar throughout all parapodia. Pygidium with one pair of pygidial cirri, which equal length of last 15 chaetigers, weakly articulated, smooth glandular margins surrounding anus (
Fig. 2F
).
Variation
. Paratypes are with branchiae starting from chaetigers 29 to 33, and with 17–21 of the posteriormost chaetigers lacking branchiae. The ratio of the length between antennae and palps varies between 1.2 and 1.5.
Remarks
.
Marphysa bulla
n. sp.
belongs to Group
B
2
sensu
Fauchald (1970)
because it has compound spinigers, but lacks falcigers, and branchiae are present along most of the body. The new species is characterised by the presence of a significantly swollen base of the ventral cirrus which changes along the body from leaf-shaped anteriorly to more rectangular posteriorly and then becoming leaf-shaped again posteriorly, but with terminal anterior rounded papillae inserted adjacent to acicular lobes (
Fig. 2C
). The new species is also characterized by the presence of three types of pectinate chaetae (thin symmetrical isodont, with varying number of teeth, thin asymmetrical isodont with varying number of teeth and thick asymmetrical anodont with few teeth) and MxII with 4+4 teeth. Of the 15 species of
Marphysa
that belong to this group (Table 1), five species (
M. borradailei
Pillai, 1958,
M. multipectinata
Liu, Hutchings & Sun, 2017
,
M. orientalis
Treadwell, 1936
,
M. tamurai
Okuda, 1934
, and
M. tribranchiata
Liu, Hutchings & Sun, 2017
) can be distinguished from
M. bulla
n. sp.
by lacking pectinate chaetae in anterior parapodia. For two species
M. furcellata
Crossland, 1903
and
M. teretiuscula
Schmarda, 1861
, the chaetiger on which pectinate chaetae begin is unknown. Of the remaining seven species,
M. fauchaldi
Glasby & Hutchings, 2010
and
M. graveleyi
Southern, 1921
, have compound spinigers restricted to anterior and median segments.
Marphysa bulla
n. sp.
has compound spinigers along the entire body like
M. mullawa
Hutchings & Karegeorgopoulis, 2003
,
M. kristiani
Zanol, da
Silva & Hutchings, 2016
and
M. macintoshi
Crossland, 1903
as well as having branchiae present along the body almost to the pygidium.
Marphysa kristiani
has only two types of pectinate chaetae, and MxII has 7+7 teeth, whereas the new species has three types of pectinate chaetae and MxII has 4+4 teeth.
Marphysa mullawa
differs from the new species in having only two types of pectinate chaetae. The other species
M. macintoshi
has only asymmetrical pectinate chaetae and with MxII having 4+5 teeth, so it also can be distinguished from
M. bulla
n. sp which has MxII 4+4.
FIGURE 2.
Marphysa bulla
n. sp.
(light microscopy images). A. Anterior end of holotype, dorsal view. B. Anterior end of holotype, lateral view. C. Anterior parapodia of holotype, lateral view, showing structure of ventral cirri. D. Jaws
in situ
, anterior view. E. Structure of branchiae from median region of holotype. F. Pygidium of holotype. A, B, C, E, H, AM.W.49124, D, AM.W.49125. Abbreviations: p, papilla vc, ventral cirrus, I, II, III, IV, V components of maxillae. Scale bars: A, B = 2 mm; C–F = 1 mm.
FIGURE 3.
Marphysa bulla
n. sp.
(A–C, SEM images, D-F, light microscopy images) A. Chaetiger 71, showing 2 tiers of compound spinigers. B. 3 types of pectinate chaetae of paratypes, left parapodia 135. C. 3 types of pectinate chaetae of paratypes, right parapodium 313. D. Left parapodium 250, showing pectinate chaetae. E. Maxillae, dorsal view. F. Mandible, ventral view. A. B, C, D—MBMCA285106; E, F—AM W.49125. Abbreviations: sp1 and sp2, 2 tiers of compound spinigers, a, thin symmetrical isodont with varying numbers of teeth, b, thick asymmetrical anodont with 3–4 teeth, c, thin asymmetrical isodont with numerous teeth, sa, subacicular hooks. Scale bars: A = 100µm; B = 20 µm; C = 50 µm; D = 0.1 mm; E, F = 1 mm.
The new species
M. bulla
is characterized by the following characters: presence of branchiae almost to pygidium, only compound spinigers, unidentate subacicular hooks, three types of pectinate chaetae as well as significantly swollen bases of the ventral cirri, this latter character we suggest represents a potentially useful new character to distinguish species in this group, although it has not previously been used.
Etymology
. The specific name
bulla
refers to the species with the lobe on the ventral cirrus, it is Latin for “knob”.
Habitat
. Intertidal, in rock crevices.
Type locality
.
Rongcheng coast, north
China
(
37.16°N
,
122.41°E
)
, see
Fig. 1
.