Paleanotus latifolia, Watson, Charlotte, 2015

Watson, Charlotte, 2015, Seven new species of Paleanotus (Annelida: Chrysopetalidae) described from Lizard Island, Great Barrier Reef, and coral reefs of northern Australia and the Indo-Pacific: two cryptic species pairs revealed between western Pacific Ocean and the eastern Indian Ocean, Zootaxa 4019 (1), pp. 707-732 : 720-722

Paleanotus latifolia n. sp.

( Figs 1 F; 5A −K)

Type material. Holotype: NTM W.23654, Eastern Indian Ocean, WA, Outer Ningaloo Reef, 22º39.33’S, 113º37.00’E, CReefs, NR-09-004, coll. CReefs team, May 2009, (1, 27E, L: 2.6 mm, W: 0.7 mm).

Other material examined. NTM W.23188, Ningaloo Reef, off northern passage near Tantabiddi, CReefs, NR- 08-9B, 21°51.40’S, 114°15’E, coll. N. Bruce, June 2008, (fragment); NTM W.23189, CReefs, NR-08-9A, coll. N. Bruce, June 2008, (1NE); NTM W.23725, Outside Channel South, Ningaloo Reef, 22º42.33’S, 113º37’E, CReefs, NR-10-008, 18 m, May 2010, (1, 17NE, anterior end); NTM W.23491, Ningaloo, CReefs, NR-08-48, (fragment); NTM W.25836, Ashmore Reef, 12°17.76’S, 123°1.63’E, Stn. K13 134-75, 3 m, 2013, coll. L. Avery, (1NE); NTM W.23709, Kimberley, Adele island, 15º31.7’S, 123º11.61’E, Stn. 3 K09, subtidal, Oct 2009, WAM & Woodside Kimberley Survey, (1, 17NE,W: 0.7 mm); NTM W.23710, Stn. 2 K09, 11−14 m, same collector, Oct 2009, (fragments); NTM W.25627, Stn.93 K12, coll. J. Finn, Oct 2012, (1, 31E); NTM W.25628, Stn.110 K12, 14º05’S, 125º36’E, coll. J. Finn, Oct 2012, (1, 24E, ovigerous female, L: 2.5 mm, W: 0.6 mm); NTM W.13179, Arafura Sea, NT, Darwin, Channel Island, 12º33’S, 130º52’E, under bridge, 0.1 m, Halimeda & coral rubble, coll. C. Watson, Dec 1986, (2: 1E, 25 segs, L: 2.1 mm, W: 0.74 mm); NTM W.13132, Darwin Harbour, Fannie Bay, Stn. D25A, fine sand & gravel, 4 m, coll. J.R. Hanley, July 1993, (fragment, W: 0.7 mm); NTM W.13115, Central Darwin Harbour, Stn. DW 51A, intertidal, gravel some sand, coll. J.R. Hanley, July 1993, (1NE); NTM W.13102, Stn. DW 53A, gravel & some sand, 8 m, coll. J.R. Hanley, Mar 1994, (1, 24NE, W: 0.8 mm); NTM W.25622, Stn. EA2/2, East Arm boat ramp, 12º29.5’S, 130º54’E, (fragment); NTM W.25629, Andaman Sea, Thailand, Similan Island, 8º38’N, 97º38’E, dead corals, coll. A. Nateewathana, Feb 1981, (4: 1, 30E, female with eggs, L: 3.4 mm, W: 0.6 mm; 1, 30E, male, L: 2.90 mm, W: 0.70 mm; 2 anterior ends); NTM W.25630, West Similan Island, from live Montipora corals, coll. A Nateewathana, Feb 1981, (1, 34E, ovigerous female, L: 3.4 mm, W: 1.00 mm).

Description. (based on holotype and other material where noted). Elongate, small body; prostomium with two pairs of dark maroon eyes. Golden shine to main paleae covering dorsum. Mid-body notopodia with 2–3(4) pointed lateral paleae with 6–7 ribs; 1– 2 sub-unit 1 paleae (often one larger, one smaller) with 6–8 ribs. Main paleae number to 10 with 12–14 (15) ribs; up to 9 b.l. ribs, 2 often full length. Main paleae with rounded brow, distinct peaked apices often with small hoods. Apices positioned slightly away from inner margin; inner distal quarter margin with fine serration similar to that of brow. Medial-most main palea slightly narrower with less asymmetric apex. Pointed median paleae number 3 with 10–12 ribs and central, full length raised rib ( Figs 1 F; 5A–C, I–K). Neurochaetae of mid-body neuropodium composed of 2 superior very long falcigers with fine serration; 2 midsuperior long falcigers (not much shorter than superior) with long serrations especially basally; about 6–8 midgroup falcigers with basal serrations; 4–6 inferior falcigers with short, slender blades ( Fig. 5 D–H).

Remarks. Paleanotus latifolia n. sp. is characterized by main paleae with a distinctive broken-line rib pattern and robust shape of its apical point and its position on a rounded brow that has fine serration on both distal margins. Females have small eggs (30–40 µm diameter, Kimberley and Thailand ( Fig. 5 I)) suggesting a different larval strategy to P. aquifolia ( Fig. 4 C) and the other five small Paleanotus species possessing large eggs described herein.

Paleanotus latifolia n. sp. is only found along the eastern Indian Ocean rim including the Arafura Sea, N Australia. Specimens from Darwin, Kimberley, Ningaloo Reef and Andaman Sea, Thailand agree in similar paleael rib numbers across all localities. One slight difference is in the shape of the main paleae: a more rounded brow is seen in material from Darwin, Ningaloo Reef, Adele Island ( Figs 1 F, 5B,K) and Thailand; a more sloping brow in specimens from other localities on the Kimberley coast.

A more symmetrical medial-most main palea is often seen in the paleal fan of Paleanotus species but is particularly obvious in P. latifolia n. sp. as observed in Darwin and Kimberley individuals ( Fig. 5 J). Mature males and females from Kimberley and Thailand agree in body and gamete size. This species clearly has more lateral paleae: one Thai specimen had the usual 2−3 laterals mid-body with 4–5 in the posterior end. Paleanotus latifolia n. sp. has been found sympatrically with P. adornatus n. sp. and P. inornatus n. sp. on the west Australian coast and with P. silus n. sp. in Thailand.

Etymology. Species name latifolia is from a Latin compound noun, meaning ‘broad leaf’. It refers particularly to the shape of the distal end of the main paleae.

Habitat / Distribution. Paleanotus latifolia n. sp. is found from the Arafura Sea, NT (Darwin), west to the Kimberley on the Sahul Shelf and Ningaloo Reef, WA, eastern Indian Ocean. It is also present on islands off the west coast of Thailand in the Andaman Sea. Occurs in sandy gravels, silty sediments and sedimented coral rubble in 1− 18 m.

Figures

FIGURE 4. Paleanotus aquifolia n. sp. A – B: NTM W. 23449: North Direction Island, GBR. A. Notopodium and neuropodium (neurochaetae omitted); B. Median and main paleae detail; C. Ovigerous female, notopodium, NTM W. 23440: Martin Reef, GBR. D – H: Neurochaetal types. D. Superior; E. Mid-superior; F – G. Mid-group; H. Inferior group; I. Micropic, notopodium in part & neuropodium; NTM W. 25843: Philippines. Abbreviations: c = cilia, e = egg, la = lateral paleae, me = median paleae, mm = medial main paleae, o. g = oil globules, sp = sperm, su 1 = sub-unit 1 palea. Scale bars: A = 200 µm, B = 30 µm, C = 100 µm, D – H = 30 µm.

FIGURE 5. Paleanotus latifolia n. sp. A – H: NTM W. 23710: Kimberley, WA. A. Male, notopodium; B. Main palea detail; C. Median palea detail; D – H: Neurochaetal types; I. Ovigerous female, micropic of notopodium, NTM W. 25628: Kimberley, WA; J. Micropic, detail of median and medial main paleae, NTM W. 13103: Darwin, NT; K. Main paleae detail, NTM W. 13103: Darwin, NT. Abbreviations: e = egg, gl = gland, la = lateral paleae, ma = main paleae, me = median paleae, mm = medial main paleae, sp = sperm, su 1 = sub-unit 1 palea. Scale bars: A = 100 µm, B – H = 30 µm.

FIGURE 1. A. Paleanotus generalized notochaetal fan; B. Main paleae sculptural detail. C – I: Comparative micropics of main palea in Paleanotus new species. C. Paleanotus inornatus n. sp., NTM W. 23684; D. P. adornatus n. sp., NTM. W. 23660; E. P. acquifolia n. sp., NTM W. 23440; F. P. latifolia n. sp., NTM. W. 23710; G. P. silus n. sp., NTM. W. 23731; H. P. silopsis n. sp., NTM W. 23186; I. P. chrysos n. sp., NTM. W. 25641. Abbreviations: b. l = ‘ broken line’sculpture, c = cilia, gl = gland, h. s = horizontal striae, la = lateral paleae, ma = main paleae, me = median paleae, r. r = raised rib, su 1 = sub-unit 1 palea.