Chloeia bimaculata, Wang & Zhang & Xie & Qiu, 2019

Wang, Zhi, Zhang, Yanjie, Xie, Yang James & Qiu, Jian-Wen, 2019, Pampus candidus, Zoological Studies (Zool. Stud.) 58 (22), pp. 12-12 : 5-8

publication ID	https://doi.org/ 10.6620/ZS.2019.58-22
persistent identifier	https://treatment.plazi.org/id/03C287A5-FFCE-FFFF-FC16-58C65A93FD82
treatment provided by	Felipe
scientific name	Chloeia bimaculata
status

Treatment

Chloeia parva Baird, 1868 View in CoL ( Figs. 3–5 View Fig View Fig View Fig ; Tables 1, 2)

Chloeia parva, Baird 1868, p. 233 View in CoL , pl. IV, fig. 8, a–b; McIntosh 1885, p. 15; Horst 1886, p. 167; Beddard 1889, p. 259; Horst 1910, p. 171; Horst 1912, p. 19, pl. VII, fig. 4, pl. VIII, figs. 1–3; Fauvel 1932, p. 56; Fauvel 1953, p. 96, fig. 46, f; Hartman 1959, p. 131; Yang and Sun 1988, p. 165, fig. 69, B–F; Liu 2008, p. 441; Barroso and Paiva 2011, p. 422, tab. 1.

Materials examined: Twelve specimens (Catalog No.: SWIMS-ANN-19-003 to SWIMS-ANN-19-014), collected from two beaches in Tsuen Wan during low tide, and subtidal waters of Tolo Harbour by trawling in 2018 ( Table 1); a non-type specimen ( BMNH 1933.3.2.7) collected from Xiamen (Amoy), China; a non-type specimen ( BMNH 1938.5.7.13) collected from Vizagapatam, India; the holotype ( BMNH 1962.3.43a) collected from unknown locality in the Indo-Pacific.

Diagnosis: Body fusiform, with around 30 segments. Dorsum with mid-dorsal “Y”-shaped dark pigmentation on each segment. Prostomium with anterior and posterior lobes. Anterior lobe with a pair of palpal antennae. Posterior lobe with 2 pairs of eyes, a pair of lateral antennae, and an unpaired median antenna. Caruncle well developed, with a wider central crest and two narrower lateral crests. Branchiae first present from chaetiger 4, bipinnate. Notopodial cirri numbering one or two per anterior segment. Notochaetae thick bifurcate, harpoon or spinose. Neurochaetae bifurcate only.

Description: Fusiform in shape, measuring 38 mm to 97 mm long, 8 mm to 20 mm wide excluding chaetae, and 33 to 39 chaetigers. Live specimens faint yellow in dorsum; chaetal fascicles similar in color with the dorsum. Fixed specimens pale, with a distinct dorsal surface pigmentation pattern: a broad dark purple line in first few chaetigers; gradually turning to the shape of Greek “Y” (upsilon) in other segments ( Fig. 3A, I, K View Fig ). A slightly curved guard bands present on left and right side and joint its hinder end in each segment ( Fig. 3A, I, K View Fig ). A pair of wide pigmented lines present on anterior margin of branchiae and notopodial chaetal fascicles in each segment, connecting guard lines in its anterior ends; a pair of inner pigmented lines present on posterior margin of branchiae and connecting guard lines; a pair of outer pigmented lines present on anterior margin of neuropodial chaetae fascicles ( Fig. 3B, I View Fig ).

Prostomium with an anterior lobe and a posterior lobe ( Fig. 3B, J View Fig ). Anterior lobe wider than long, with a pair of cirriform and pale palpal antennae. Posterior lobe smaller, with a pair of lateral antennae arising from its anterior margin, stouter and slightly shorter than palpal antennae ( Fig. 3B, J View Fig ). One median antenna arising from the anterior base of the caruncle, stouter and similar in length with lateral antennae, and about one fifth the length of the caruncle, with purple pigmentation only on posterior side ( Fig. 3B, J View Fig ). Palps fused, forming a shallow mid-dorsal groove with a dark purple line on bottom, and a pale mid-ventral longitudinal groove extending to mouth ( Fig. 3C, J View Fig ). Two pairs of dark eye spots arranged trapezoidally on posterior prostomial lobe, anterior two eyes slightly larger ( Fig. 3B, J View Fig ; the dark pigment of the eye spots in some specimens faded after preservation in ethanol). Caruncle consists of a wider central crest and two narrower lateral crests, each covered with ~12 transverse folds ( Fig. 3B View Fig ). In specimens with an intact crest, summit of caruncle with an undulated bead-like purple line ( Fig. 3J View Fig ). Base of caruncle fused on the first two chaetigers and extends posteriorly to third chaetiger ( Fig. 3B View Fig ). Mouth surrounded by ventral palps and ventral side of first three chaetigers ( Fig. 3C View Fig ).

All parapodia biramous with widely separated doral and ventral rami ( Fig. 3G, H View Fig ). Branchial cirri inarticulate, pale in color, only present in the first three parapodia, more dorsal to, and slender and shorter than notopodial cirri ( Fig. 3B, G View Fig ). Notopodial cirri biarticulate, cirrophore partially marked with dark purple pigmentation, but pigmentation fades in preserved specimens; cirrostyle marked with slight purple in the first three parapodia, and in dark purple from the fourth parapodia onwards; cirrostyle about 3–4 times the length of cirrophore; all notopodial cirri located posteriorly to the chaetal fascicles ( Fig. 3G, H View Fig ). Neuropodial cirri biarticulated; cirrophore shorter than cirrostyle; cirrophore and cirrostyle in all parapodia pale ( Fig. 3D, G, H View Fig ).

Branchiae bright red in living worms; bipinnate, present from fourth parapodia to posterior end ( Fig. 3A View Fig ); with 10–20 alternating branches arising from primary stem, each terminating in smaller branches or digitiform terminal filaments ( Fig. 3H, I, K View Fig ). Branchiae smaller in anterior chaetigers, best developed in middle chaetigers to near end and decreasing in size in last few chaetigers ( Fig. 3A View Fig ). All branchiae with purple pigmentation marked on inner side of primary branchial stems ( Fig. 3A, I, K View Fig ).

Notochaetae three types: (1) bifurcate chaetae ( Fig. 4A–C View Fig ), distal teeth varying in length and width, only present in the first five chaetigers; (2) harpoon chaetae ( Fig. 4D–G View Fig ), with harpoon-shaped serrations on unilateral side of the spinous stem below the apex, with ~ 7 lateral serrations in anterior chaetigers to larger than 20 lateral serrations in middle and posterior chaetigers, present from chaetiger 6 to posterior end, most numerous among the three types of chaetae; (3) spinose chaetae without serrations, located in superior chaetal fascicles, present from anterior to posterior chaetigers, several, least numerous among the three types ( Fig. 4H View Fig ). Neurochaetae thinner, longer, and more numerous than neuropodial chaetae in the majority of chaetigers ( Fig. 3H View Fig ). Neurochaetae bifurcate chaetae only ( Fig. 4I–L View Fig ), similar in morphology with bifurcate notochaetae ( Fig. 4A–C View Fig ), distributed in all parapodia; tips of distal teeth in anterior chaetiger amber, short and blunt, but longer and sharper in posterior chaetigers ( Fig. 4I–L View Fig ).

Pygidium with a terminal anus on dorsal side ( Fig. 3F View Fig ). A pair of pygidial cirri digitiform, as long as the last 4 chaetigers ( Fig. 3E, F View Fig ).

Habitat: Subtidal soft bottom, depth less than 20 meters; intertidal sandy bottom.

Distribution: Our specimens were collected from beaches of Tsuen Wan, and subtidal waters of Tolo Harbour, Hong Kong during an outbreak of this species. Based on previous literature ( Fauvel 1953) as well as our observation of photographs posted by divers onto the Internet, this species should be widespread in South China Sea. However, records from the Indian Ocean ( Fauvel 1932) need further study.

Molecular Analysis

Phylogenetic trees ( Fig. 5 View Fig ) were built based on partial DNA sequences of three genes [i.e., COI (637 bp), 16S rRNA (451 bp) and 28S rRNA (958 bp)] and their concatenated sequences (2046 bp). All of the phylogenetic trees show that the Chloeia species form a monophyletic clade. According to the concatenated sequences, C. bimaculata sp. nov. and C. parva are the most closely related within the selected species. Besides, the interspecific divergences within Chloeia species are 16.8–23.6% for COI, 4.6–10.0% for 16S, 0.6–2.4% for 28S and 6.2–10.7% for the concatenated sequences ( Table S1), which is much larger than the maximum intraspecific divergences of corresponding sequences (2.6%, 0.7%; 0, and 0.9%). These analyses; therefore, support C. bimaculata sp. nov. and C. parva as two distinct species.