Chloeia bistriata Grube 1868

Chloeia bistriata Grube, 1868

Figs 6, 14

Chloeia bistriata Grube, 1868a: 50; Grube 1868b: 631–633, Pl. 7, Fig. 2.

Chloeia fusca: Potts 1909: 356, Pl. 45, Figs 1, 2; Horst 1917: 285–286; Fauvel 1932: 56 (partim, Investigator Sta. 614), 1953: 97, Fig. 46d; Monro 1937: 253; Hartman 1959: 131; Amoureux et al. 1978: 73; Fauvel 1957: 4; Day 1967: 124, Fig. 3.1.s (partim, non M’Intosh 1885).

Type material. Red Sea. Neotype (SMF 19403) and two paraneotypes (SMF 30268), Gulf of Aquaba, in front of Marine Science Station, seagrass meadow of Halophila stipulacea (Forskål, 1775), 22.5 m, 25 Mar. 2007, T. Wehe & Y. Ahmed, coll. (paraneotypes complete, largest one bent ventrally; middorsal bands discontinuous along all segments in smallest paraneotype, and in largest paraneotype discontinuous along anterior chaetigers, continuous in posterior ones; anterior prostomial area blackish; anterior eyes 2–5× larger than posterior ones; lateral bands not visible; lateral antenna purplish; dorsal cirri dark purple; branchiae pale; body 4.5–20.0 mm long, 2–5 mm wide, 14–23 chaetigers).

Additional material. Red Sea. Gulf of Aquaba. Five specimens (SMF 19382), no depth or date data, T. Wehe, coll. (early juveniles; dorsal discontinuous dark purple bands visible along body, transverse bands better defined in two largest specimens; dorsal cirri dark purple; branchiae from chaetiger 5, not present in smallest juvenile, better visible in larger juveniles; anterior prostomial area blackish; eyes 2–4× larger than posterior ones; body 1.2–3.5 mm long, 0.6–1.5 mm wide, 10–18 chaetigers). Saudi Arabia. One specimen (UF 3543), off Thuwal, Shark Reef (22.4268, 38.9963; 22°25´36.48″ N, 38°59´46.6794″ E), offshore reef, sheltered side, depth not specified, 18 Mar. 2013, A. Anker, P. Norby & J. Moore, coll. (without posterior end; pharynx partially exposed; anterior prostomial area brownish; eyes black; anterior dorsal cirri purple, most pale; 8 mm long, 2.5 mm wide, 14 chaetigers). One specimen (UF 4189), juvenile, Thuwal, Shi’b Nazar (22.3481, 38.8526; 22°20´53.1594″ N, 38°51´9.36″ E), 9–12 m, reef slope, under rock, 2 Mar. 2014, G. Paulay & M Roberts, coll. (pharynx partially exposed; eyes reddish; middorsal bands thin, fading; branchiae with 5–6 lateral branches; neurochaetal furcates with tines sharp, major ones 3–5× longer than minor ones; 9.3 mm long, 2 mm wide, 17 chaetigers). One specimen (UF 4215), Shi’b Al Karrah (22.9378, 38.7657; 22°56´16.0794″ N, 38°45´56.52″ E), 4–12 m, reef on sand bank, 5 Mar. 2014, G. Paulay, coll. (complete; middorsal bands, lateral antennae, dorsal cirri and branchial filaments dark purple; eyes black; anterior prostomial area blackish; 8 mm long, 3 mm wide, 17 chaetigers). One specimen (UF 4444), Shib Suflani (22.9705, 38.3702; 22°58´13.8″ N, 38°22´12.7194″ E), 5–25 m, offshore patch reef, exposed wall, 29 Jan. 2016, J. Moore, coll. (juvenile, middorsal bands blackish, transverse and oblique bands brownish; eyes black; all antennae brownish; dorsal cirri barely purple; all branchiae cirriform; 2.6 mm long, 0.9 mm wide, 11 chaetigers). Three specimens (UF 4449), juveniles, Yanbu Harbor (24.0718, 38.0516; 24°4´18.4794″ N, 38°3´5.76″ E), 0–1 m, in Turbinaria seaweeds, 29 Jan. 2016, J. Moore, coll. (eyes and dorsal bands blackish, continuous, not interrupted intersegmentally; branchiae with 1–2 filaments; 1.5–1.6 mm long, 10–11 chaetigers). One specimen (UF 4508), juvenile, Yanbu Marker 29 (24.005833, 37.884778; 24°0´20.9982″ N, 37°53´5.2002″ E), 15–25 m, patch reef, 3 Feb. 2016, J. Moore, coll. (bent ventrally, eyes and dorsal bands blackish, interrupted segmentally; median antenna and branchiae brownish; branchiae with 1–2 filaments; 2.2 mm long, 0.9 mm wide, 12 chaetigers). Five specimens (UF 4517), Shib As Sahah (23.804, 37.9316; 23°48´14.3994″ N, 37°55´53.76″ E), sheer coral reef wall with sand, 42 m, 4 Feb. 2016, J. Moore, coll. (two removed for SEM; middorsal bands and eyes black; dorsal cirri purple; largest specimen with median antenna 2× longer than caruncle; bipinnate branchiae along chaetigers 5–7 in 4 mm long specimen; body 3.3–4.9 mm long, 1.2–2.0 mm wide, 15–18 chaetigers). Arabian Sea. One specimen (BMNH 1937.9.2.14), Gulf of Aden, John Murray Expedition, HEMS Mabahiss, Sta. 27 (11°57´12″ N, 50°35´00″ E to 11°55´42″ N, 50°39´12″ E), 37 m, 12 Oct. 1933 (body yellowish, anterior end distorted after compression by label; dorsal bands visible throughout body, thinner in intersegmental areas; lateral bands oval, orange to brownish, about as long as 1/3–1/2 segmental length; anterior prostomial area blackish, caruncle brownish; dorsal cirri dark purple; bipinnate branchiae from chaetiger 5, stem orange, branches dark purple; anterior eyes 4× larger than posterior ones; venter brownish, midventral band whitish; body twisted, 16 mm long, 4 mm wide, 18 chaetigers). One specimen (BMNH 1937.9.2.15), Gulf of Aden, John Murray Expedition, HEMS Mabahiss, Sta. 178 (12°00´36″ N, 50°40´06″ E), 91 m, 2 May 1934 (body yellowish; dorsal bands better defined along anterior and posterior chaetigers, medially faded off; lateral bands not seen; anterior prostomial area and caruncle blackish; dorsal cirri dark purple; bipinnate branchiae from chaetiger 5, stem purple to pale, branches purple to pale; anterior eyes 2× larger than posterior ones; venter brownish, midventral band whitish; body slightly bent ventrally, 6 mm long, 2 mm wide, 18 chaetigers). One specimen (BMNH 1937.9.2.16), off South Arabia, John Murray Expedition, HEMS Mabahiss, Sta. 43 (17°29´00″ N, 55°47´00″ E), 83–100 m, 28 Oct. 1933 (bent ventrally; dorsal bands visible only in posterior chaetigers; anterior prostomial area and caruncle blackish; dorsal cirri and base of branchiae dark purple; anterior eyes 2–3× larger than posterior ones; venter brownish, midventral band whitish; body breaking medially, 20 mm long, 4 mm wide, 23 chaetigers). Zanzibar. One specimen (BMNH 1937.9.2.17), off Zanzibar, John Murray Expedition, HEMS Mabahiss, Sta. 111 (05°04´18″ S, 39°14´12″ E), 73 m, 14 Jan. 1934 (posterior fragment, without pygidium; dorsal bands, cirri and branchiae dark purple; chaetae yellowish; two parapodia previously removed; fragment 5.5 mm long, 2.3 mm wide, 11 chaetigers). Madagascar. One specimen (MNHN A861.1), Sta. 14 (12°43.3´S, 48°15.7´E), 245–255 m, 15 Apr. 1971, A. Crosnier, coll. (slightly bent ventrally; dorsal bands and branchiae purplish; dorsal cirri dark purple; anterior eyes 3× larger than posterior ones; body 16.5 mm long, 4 mm wide, 23 chaetigers). South Africa. Two specimens (RMNH 1244), Natal Bay, Durban, 1874, M. Weber, coll. (details in variation).

Diagnosis. Bipinnate branchiae from chaetiger 5; dorsum with two longitudinal bands; caruncle homogeneously brownish; lips pale, resembling adjacent ventral areas; notochaetae furcates and harpoon chaetae furcates; neurochaetae furcates.

Description.

Neotype (SMF 19403) with body fusiform (Fig. 14A), bent ventrally, complete, 15 mm long, 5 mm wide, 22 chaetigers.

Neotype with middorsal bands discontinuous along anterior body half, continuous along posterior one; anterior prostomial area dark purple (Fig. 13B); lateral antennae purplish; dorsal cirri dark purple; branchiae pale. Venter cream, midventral band paler, visible along body.

Prostomium anteriorly entire. Eyes blackish, anterior eyes 6× larger than posterior ones (Fig. 14D). Median antenna inserted at anterior caruncular margin, as long as caruncle, about 3× longer than lateral antennae. Lateral antennae bases separate from each other, 2× longer than palps. Mouth ventral on chaetiger 2/3. Pharynx not exposed.

Caruncle pale, straight, trilobed, tapered, reaching chaetiger 4. Median ridge plicate, with about 12 vertical folds, almost completely concealing lateral lobes. Lateral lobes narrow, with about 16 vertical folds.

Bipinnate branchiae from chaetiger 5, parallel throughout body, progressively larger to chaetiger 9–10, smaller posteriorly. Median segments with 6–7 lateral branches.

Parapodia biramous, notopodia with cirriform branchiae along chaetigers 1–4, slightly shorter than dorsal cirri. Dorsal cirri 2× longer than bipinnate branchiae along median chaetigers, 3× longer in posterior chaetigers. Second ventral cirri with cirrophores 2× longer and wider, and cirrostyle 2× longer than adjacent ones, directed dorsally. Other ventral cirri directed ventrolaterally, as long as 1.5 subsequent segments.

Chaetae most complete, distal hoods rarely eroded. Notochaetae in anterior chaetigers furcates (Fig. 14E), major tines 2–5× longer than minor ones. Median chaetigers with two types of notochaetae (Fig. 14G): furcates with reduced minor tines, major ones 3–5× longer than minor ones, and a few harpoon-chaetae with smooth tines ¼–1/5 as long as denticulate ones. Neurochaetae all furcates, major tines 5–6× longer than minor ones in anterior chaetigers (Fig. 14F), and 5–7× longer than minor ones in median chaetigers (Fig. 14H).

Posterior end tapered (Fig. 14C), anus terminal; anal cirri whitish, digitate, 2–3× longer than wide.

Live pigmentation. Unknown. Smaller specimens show discontinuous middorsal bands along body, becoming continuous along posterior segments; lateral bands thin, running along anterior parapodial surfaces. Larger specimens with additional pigmentation along dorsal surface, including orange spots.

Variation. Small Red Sea specimens (UF 4449, 4517) have continuous black dorsal bands, and brownish diverging bands extended laterally as dark purple or black bands, and yellowish areas in prostomium and caruncle (Fig. 6A); eyes are black, anterior eyes 2× larger than posterior ones (Fig. 6D). Bipinnate branchiae start in chaetiger 5 (Fig. 6B, C, E, F), and they progressively replace cirriform branchiae along body.

Straight South African specimen (RMNH 1244), 16 mm long, 4 mm wide, 21 chaetigers. Two dorsal blackish bands, continuous throughout body; lateral bands paler, better defined along posterior chaetigers, continued along anterior notopodial surface, often extended backwards separating parapodial rami. Anterior prostomial area blackish. Caruncle brownish. Cirriform branchiae and dorsal cirri blackish; bipinnate branchiae from chaetiger 5, with pale stems, lateral branches with purple tips. Venter pale, including lips; midventral band paler. Chaetae yellowish to transparent. Caruncle brownish, reaching chaetiger 4. Median ridge with about 16 vertical folds; lateral lobes narrow, with about 18 vertical folds. Bipinnate branchiae from chaetiger 5, parallel throughout body, progressively larger to chaetiger 11–12, smaller posteriorly; in median segments each with 6–7 lateral branches. Anterior notochaetae furcate, major tines 3–4× longer than minor ones. Median notochaetae furcates with reduced shortest tines, longest ones 3–7× longer than shortest ones, and harpoon-chaetae, shortest tine 1/5 as long as main one. Neurochaetae all furcates, major tines 4–5× longer than minor ones. Anus terminal; anal cirri pale, globose, 3× longer than wide.

Another South African specimen (RMNH 1244b), bent ventrally, 19 mm long, 4 mm wide, 23 chaetigers. Pigmentation pattern as in the other specimen, better defined along anterior region, parapodial pigmentation reaching ventral surfaces along anterior chaetigers. Eyes separate; anterior eyes 4× larger than posterior ones. Caruncle brownish, reaching chaetiger 3. Bipinnate branchiae from chaetiger 5, stems pale, lateral branches purplish. Anal cirri pale, globose, right one single, left one trifid, all of similar size.

Remarks. A neotype is herein proposed for Chloeia bistriata Grube, 1868 and these are the qualifying conditions (ICZN 1999, Art. 75.3): The neotype is being proposed for clarifying the taxonomic status of the species (Art. 75.3.1), because it was briefly described and reported twice by the same author (Grube 1868a, b). The characters that can be used to separate C. bistriata from similar species (Art. 75.3.2) have been included above in the key to species, are further explained below, and were incorporated in the description and illustrations above (Art. 75.3.3). The corresponding curators where other specimens described by Grube are deposited (Berlin, Wroclaw), have indicated there is no type material of C. bistriata (Art. 75.3.4). The morphology of the neotype conforms to the characters included in the original description and illustration (Art. 75.3.5). The type locality was indicated as Red Sea for this, and other species collected by Georg Ritter von Frauenfeld, described by Grube, and deposited in Berlin or in Wroclaw (Hartwich 1993, Wiktor 1980); the neotype was collected in the Gulf of Aquaba, and there are three traditional resort cities in its northern part which might have also attracted the original collector, but there is no means to confirm this, and there were no details in the obituary either (Brunner von Wattenwyl 1873). Consequently, there is no evidence that the neotype “came as nearly as practicable from the original type locality” (Art. 75.3.6), but the neotype was collected in the Red Sea without any further detail. The neotype is the property of the Senckenberg Museum in Frankurt, which maintains a very important polychaete collection including many type specimens (Fiege & Wehe 2004), and that has made them available for taxonomic studies (Art. 75.3.7).

Chloeia bistriata Grube, 1868, described from the Red Sea, belongs in the group fusca, together with C. fusca M’Intosh, 1885, described from Indonesia, by having branchiae from chaetiger 5 and double middorsal bands. The main differences between these two species are in the size of eyes and in caruncular complexity. In C. bistriata anterior eyes are 6× larger than posterior ones, and its caruncular median ridge has 12 vertical folds, whereas in C. fusca the anterior eyes are 3–4× larger than posterior ones, and the median ridge of its caruncle has 18 vertical folds.

Potts (1909: 356) noted a significant difference in pigmentation and that the median antenna is longer than the caruncle. The pigmentation of specimens he studied from the Amirante Islands, Maldives, includes two longitudinal thin purple lines middorsally, each slightly enlarged medially, and crescentic orange marks parallel and external to the purple lines. Reddish and orange colors fade off soon in ethanol, but the purple half rings under notochaetae are visible.

Horst (1917: 286) noted in South African specimens that ‘the two dorsal stripes appear to be much thinner than in the Malayan species.’ However, he also indicated that ‘the median tentacle appears to be shorter and does not much exceed half the length o the caruncle, whereas in the Banda specimens it is nearly of the same length or somewhat longer.’ Monro (1937: 253) noted that “all specimens have a yellowish body colour and a pair of purple longitudinal dorsal stripes showing various degrees of fading.”

On the other hand, the type of C. longisetosa has 21 segments, and although Potts did not give the number of segments for C. fusca, it is enigmatic how the former could be regarded as the epitoke of the latter, although Potts indicated these two species were similar. This pigmentation resembles the one described for C. bistriata Grube, 1868 for the Red Sea.

McIntosh (1925: 15) noted for C. gilchristi recorded from off Durban, from sediments in 65 m water depth. He indicated that “the dorsum is marked by two madder-brown lines which are boldest in front and get hinner posteriorly” and this matches the C. bistriata Grube, 1868 pattern, and the one of C. fusca M’Intosh, 1885. However, McIntosh added that “the absence of serrate bristles of any kind in this species is a feature of note, both dorsal and ventral being quite smooth” (McIntosh 1925: 17), and this feature matches C. bistriata rather than C. fusca, which has denticulate or serrate notochaetae.

Chloeia bistriata Grube, 1868 was recorded from South Africa as C. fusca M’Intosh, 1885, described from Indonesia, by Horst (1917: 285–286). Horst referred to a dozen specimens, but only two are left; he indicated that the main difference with C. fusca topotypes (see below) was the length of the median antenna, being shorter than caruncle (half its length), in Durban specimens, whereas in the topotypes it is about as long as caruncle. However, South African specimens of C. bistriata have their median antenna broken, and this cannot be used to separate species because of its fragility. The most relevant differences are in pigmentation of the caruncle and lips; in C. bistriata the caruncle is homogeneously darker, and lips are as pale as adjacent areas, whereas in C. fusca the caruncle is pale, and the lips are usually darker than surrounding areas.

The specific epithet was given after the pigmentation pattern: “two median dorsal black bands interrupted segmentally” (Grube 1868: 631); chaetae were described as smooth (without serrations) (Grube 1868: 632). It is interesting that in small juveniles (Fig. 2A), the dorsal bands are not interrupted segmentally and that oblique lines are directed anteriorly and then run laterally along anterior surfaces of notopodia. However, in slightly larger specimens, being 3.5 mm long (Fig. 2D), intersegmental discontinuities, and purple dorsal cirri are visible. However, as indicated above, there are harpoon notochaetae but they are a few, and probably were not found by Grube.

Distribution. Red Sea, Arabian Sea to Madagascar, in sediments from the intertidal to 255 m water depth.