Paradalhousia papillosa ( Monro, 1926 ), 2020

Salazar-Vallejo, Sergio I., 2020, Revision of Leocrates Kinberg, 1866 and Leocratides Ehlers, 1908 (Annelida, Errantia, Hesionidae), Zootaxa 4739 (1), pp. 1-114 : 88-90

Paradalhousia papillosa ( Monro, 1926) reinst., n. comb.

Figure 51

Leocrates papillosus Monro, 1926: 313 ;

Leocrates giardi: Pettibone 1970: 219–221 , Fig. 17–19 (partim, only figure 19, non Gravier, 1900).

Type material. China Sea. Two syntypes ( BMNH 1926.4.30.130–131), Macclesfield Bank (16°00’ N, 114°30’ E), no further data [very damaged after chaetal fracture and removal of many parapodia; description based upon both of them] .

Additional material. Sibuyan Sea. One specimen ( MNHN Musorstom 3-137), Philippines, Sta. 137 (12°03’ N, 122°06’ E), 56 m, 6 Jun. 1985 [8.5 mm long, 1 mm wide].

Description. Syntypes (BMNH 1926.4.30.130–131) complete, smaller syntype better preserved, slightly bent laterally ( Fig. 51A ). Body 12 mm long, 2 mm wide, 16 chaetigers; left parapodia of chaetigers 8–10 and, right parapodia of chaetigers 6, 7, 9 and 12 previously removed. Larger syntype slightly bent laterally and ventrally. Body 13 mm long, 2 mm wide, 16 chaetigers; left parapodia of chaetigers 8–9, and right parapodia of chaetigers 2, 3, 9–11 previously removed; right parapodia of chaetiger 8 removed for observing parapodial features (kept in container with syntypes). Pharynx with a longitudinal, and a transverse previously made dissections. Body pale, eyes and peristomial middorsal tubercle brownish; most cirri missing.

Prostomium longer than wide, wider anteriorly ( Fig. 51B ). Lateral antennae with ceratophores distinct, without tips in smaller syntype, almost as long as prostomium, longer than palps in larger syntype; palpophores slightly longer than palpostyles. Median antenna tiny, probably eroded, tapered, inserted centrally between eyes.

Eyes brownish, round; anterior eyes emarginate anteriorly, slightly larger and slightly more distant to each other than posterior round ones; in lateral view anterior and posterior eyes distinct ( Fig. 51B ).

Nuchal organs lobes U-shaped, parallel to convergent, prostomial posterior projections pale; middle furrow deep. Lateral ciliated bands visible dorsally. Tentacular cirri broken, one ventral incomplete one reaches chaetiger 1. Lateral cushions swollen, projected, entire along body, longitudinal striae visible.

Pharynx fully everted in smaller syntype ( Fig. 51C ); anterior margin with 20 small, oval denticles, middorsal and midventral areas bare. Upper and lower jaws single, tiny, barely pigmented (an irregular fleshy projection ahead of dorsal jaw).

Chaetigers 1–3 without notochaetae; notochaetae present along chaetigers 4–16, about 50 per bundle, delicate, many broken; if entire, approaching neurochaetal tips, subdistal denticles mostly eroded, visible in a few chaetae, fine. Notacicular and neuracicular lobes tapered, pointed ( Fig 51D ); notacicular lobes twice longer than wide, neuracicular ones as long as wide. Neurochaetae broken in most chaetigers, about 20 per bundle, blades bidentate, 11–13 times longer than wide, guards approaching subdistal tooth ( Fig. 51D , inset).

Posterior region tapered. Prepygidial segment without cirri, dorsal cirrophores twice wider than ventral ones. Pygidium with anus terminal, anal cirri missing.

Oocytes not seen.

Variation. A non-type, better-preserved small specimen (MNHN Musorstom 3-137) has about 30 neurochaeta per bundle, and their blades are 4–16 times longer than wide. The illustration by Pettibone (1970, Fig. 19e ) based upon the study of the syntypes indicates they were 5–11 times longer than wide.

Remarks. Paradalhousia papillosa ( Monro, 1926) n. comb. is reinstated because it was regarded as a junior synonym of Leocrates giardi Gravier, 1900 by Pettibone (1970: 219), but they belong to different genera. Further, P. papillosa is newly combined into Paradalhousia because it has U-shaped nuchal organs, single upper and lower jaws, and pale neurochaetae. On the other hand, P. papillosa differs from P. oculata ( Treadwell, 1906) especially in the number of neurochaetae, and in the orientation of their distal teeth. In P. papillosa there are about 20(–30) neurochaetae per bundle, and their distal teeth are straight, whereas in P. oculata there are about 50 neurochaetae, and their distal teeth are falcate.

Monro (1926) included this species from the Macclesfield Bank, South China Sea, as a part of the third contribution from the HMS Alert Expedition samples ( Monro, 1926). However, that voyage did not include the China Sea, as can be confirmed elsewhere ( Coppinger 1884, Günther 1884). Consequently, the collector attribution, or field data are undefined, but the locality is regarded as precise, albeit the depth was not indicated in the third contribution. For the first two contributions ( Monro 1924a, b), other species were recorded from the same site from stations made at 54–65 m, 54–81 m, 54–90 m, 90– 108 m. However, sampling was made by two vessels: HMS Rambler in early 1888, and HM Surveying-Vessel Penguin in early 1892, and all specimens were deposited in The Natural History Museum, London ( Anonymous 1895). The corals collected during the first survey were reported by Bassett-Smith (1890), who included the description of five new species, and also included a map with depth data and collecting stations.

Distribution. Macclesfield Bank (E Paracel Islands) to the Philippine Islands, in mixed bottoms, 54–108 m depth.

Figures

FIGURE 17. Lamprophaea cuprea Grube, 1867, reinstated, largest non-type specimen (USNM 19194). A. Anterior region, dorsal view. B. Anterior end, dorsal view. C. Chaetiger 8, right parapodium, anterior view, MGS (insets: notacicular and neuracicular lobes). D. Same, neurochaetae. Scale bars: A: 1.4 mm, B, C: 0.3 mm, D: 80 µm.

FIGURE 18. Lamprophaea longicirrata (Treadwell, 1902), new combination, holotype (USNM 15915), MGS. A. Anterior region, dorsal view. B. Anterior end, dorsal view. C. Anterior end, ventral view. D. Chaetiger 10, right parapodium, anterior view (insets: longest and shortest neurochaetal blades, and notacicular lobe). Scale bars: A: 0.7 mm, B, C: 0.6 mm, D: 0.9 mm.

FIGURE 19. Lamprophaea ockeri n. sp., holotype (LACM 10143). A. Anterior region, dorsal view. B. Anterior end, dorsal view. C. Chaetiger 8, left parapodium, anterior view, MGS. D. Same, neurochaetal blades including longest and shortest ones. Scale bars: A: 1.2 mm, B: 0.8 mm, C: 0.5 mm, D: 0.1 mm.

FIGURE 51. Paradalhousia papillosa (Monro, 1926) new combination, reinstated, smaller syntype (BMNH 1926.4.30.130– 131). A. Dorsal view. B. Anterior end, dorsal view, MGS. C. Same, ventral view. D. Larger syntype, chaetiger 8, right parapodium, anterior view, MGS (insets: notacicular lobe, remaining neurochaetal blades). Scale bars: A: 0.9 mm, B: 0.3 mm, C: 0.4 mm, D: 0.2 mm.