Laonice olgae, Sikorski, Andrey & Pavlova, Lyudmila, 2016

Sikorski, Andrey & Pavlova, Lyudmila, 2016, Three new species of Laonice (Polychaete: Spionidae) from West and Southwest Africa, Zootaxa 4097 (3), pp. 353-368 : 359-361

Laonice olgae sp. nov.

( Figures 4 A–B, 5)

Laonice cirrata — Day 1961: 484 (partim).

Holotype: University of Cape Town’s Ecological Survey, R/V “Africana I”, AFR 728 IIj, 31°14.1ʼS, 16°36.5ʼE, 272 m, dredge, “Polyzoa and rock”, 70% ethanol, 15 Aug. 1947, det J.H. Day as Laonice cirrata ( Sars, 1851) —( SAM A20531).

Anterior fragment of 1.1 mm width containing 51 chaetigers.

Prostomium not obviously fused to the peristomium by the anterior margin (membrane connecting the prostomium and peristomium present but is hidden in the groove between the two). Prostomium is bell-shaped ( Fig. 4 A) with two large nearly discoloured eye-spots in the posterior, with large cylindrical occipital papilla on the level of chaetiger 1. Caruncle well developed, extending together with nuchal organ to chaetiger 9.

Branchiae present until chaetiger 29. Branchiae much shorter than notopodial postchaetal lobes on chaetiger 2, becoming longer on chaetiger 3 (but still shorter than notopodial postchaetal lobes). Branchiae longer than notopodial postchaetal lobes from chaetiger 5. Notopodial postchaetal lobes are significantly enlarged on chaetigers 3 and 4 and are erect (otherwise they could overlap mid-dorsally). Notopodial postchaetal lobes are of maximum size on chaetiger 4. Notopodial postchaetal lobes with acute upper tips up to and including the fourth segment. No acute tips from chaetiger 5, but notopodial postchaetal lobes extend upwards having acute tips visible on the lateral margins of lobes on the branchial segments. The lobes become (on 7 of the following segments) rounded (not extended upwards) with acute peak on the middle of lateral margin. The upper margin of notopodial postchaetal lobes fused to the body wall, shifting toward the dorsal surface of the body at the end of fragment. Transverse dorsal membranes absent. Neuropodial postchaetal lobes rounded, with obvious peaks in the middle of outer margin from chaetiger 13 which become acute from chaetiger 18 or 19. Tips on neuropodial postchaetal lobes disappear from chaetiger 34 and the lobes become posteriorly smaller and rounded. First genital pouches are visible on chaetiger 33 on the left and on chaetiger 32 on the right side.

Neuropodial hooded hooks appear on chaetiger 36, up to 11 per neuropodium; hooks are bidentate in side view ( Fig. 4 B), but main fang is surmounted by pair of apical teeth. Notopodial hooks not detected. Sabre chaetae appear from chaetiger 19, up to 2 per neuropodium.

Pygidium unknown.

Methyl green staining pattern. No special pattern detected, but upper halves of anterior surfaces of notopodial postchaetal lobes on chaetigers from 4 to 6 keep a bit more staining comparing to other body parts.

Distribution. South Africa, north of Cape Town, 272 m ( Fig. 5 ).

Etymology. The name of the species is derived from the name (Olga) of the daughter of the author—A. Sikorski.

Remarks. This specimen is morphologically very close to the species L. sarsi known from the Northeastern Atlantic. We can also suppose that notopodial hooded hooks may be present in L. olgae as in L. sarsi . The main difference is that this specimen has such remarkably enlarged notopodial postchaetal lobes on chaetigers 3 and 4. Besides that this specimen and L. sarsi are distinguishable by differences between the number of chaetiger with last visible branchiae and with first visible genital pouches (- 3 in L. olgae and - 1 to 12 in L. sarsi ) and by difference between the number of chaetiger with first visible sabre setae and with first visible genital pouches (- 13 in L. olgae and -11 to 10 in L. sarsi ). These differences appear sufficient for description of a new species.

Figures

FIGURE 4. Laonice olgae sp. nov. (Holotype, SAM A 20531): A. Anterior end, general dorsal view; B. Hooded hook, chaetiger 51 (side view). Scales (mm): A— 1; B— 0.15.

FIGURE 5. Distribution of the new species along the African coast: filled circles— Laonice galatheae sp. nov.; square— Laonice cricketae sp. nov.; triangle— Laonice olgae sp. nov.