Levensteiniella longqiensis, Han & Zhou & Chen & Wang, 2024

Han, Yuru, Zhou, Yadong, Chen, Chong & Wang, Yueyun, 2024, Diversity and biogeography of scale worms in the subfamily Lepidonotopodinae (Annelida: Polynoidae) from Indian Ocean hydrothermal vents with descriptions of four new species, Zoological Journal of the Linnean Society 201 (2), pp. 290-304 : 294-295

Levensteiniella longqiensis sp.nov.

( Fig. 3 )

ZooBank registration: urn:lsid:zoobank.org:act:DDF94337-2990-4CF4-A28A-21F1D2CB2BEE .

Polynoidae sp. 2— Zhou et al. 2018b.

Diagnosis: Small-sized Levensteiniella with oval prostomium. Two pairs of short, ventral papillae present on segments 11 and 12 for some individuals. Notochaetae with one row of pocketlike spines, which then separate into two rows.

Type locality: Longqi vent field, SWIR .

Type material: Holytype ( RSIO35287 ): incomplete in the posterior part, Longqi vent field (37.78°S, 49.65°E, 2760 m deep), SWIR, Dive 94, 11 January 2015. Paratype ( RSIO35289 ): incomplete, same for holotype. All specimens were fixed and stored in 95–100% (v/v) ethanol .

Description: Anterior 14 segments remaining on holotype ( Fig. 3A, B ) and paratype, elytra lost ( Fig. 3A ), seven pairs of prominent elytrophores on dorsal segments 2, 4, 5, 7, 9, 11, and 13 on holotype ( Fig. 3A ). Chaetae often coated with polymetallic sulphides ( Fig. 3A, B ).

Prostomium oval, deeply bilobed ( Fig. 3C, D ), anterior lobes subtriangular with tapering lateral antennae ( Fig. 3C ). Median antenna inserted into anterior notch, with short, cylindrical ceratophore and subulate style bearing a long filament ( Fig. 3C, D ). Palps stout, tapering slightly with long, terminal filaments ( Fig. 3C, D ). First segment achaetous, fused to prostomium, not visible dorsally; two pairs of tentacular cirri long, slender, and tapering with short, cylindrical tentaculophores ( Fig. 3C, D ). Segment 2 with biramous parapodia bearing the first pair of elytrophores ( Fig. 3C ); ventral cirri attached basally to neuropodia, tapering, with long filaments and much longer than the following ventral cirri ( Fig. 3D ). Mouth located between segments 1 and 2 ventrally ( Fig. 3D ).

Parapodia biramous, notopodium short with notochaetae ( Fig. 3E, F ); neuropodium with projecting acicular lobe ( Fig. 3F ). Notochaetae are usually covered in sulphide minerals and shorter than neurochaetae ( Fig. 3E, F ), with one row of pocketlike spines distributed in distal part and separated into two groups of prominent, sharp spines close to the tips ( Fig. 3G ). Neurochaetae numerous ( Fig. 3E, F ), with two rows of pointed spines tapering toward tips ( Fig. 3H ). Dorsal cirri with long, cylindrical cirrophores and extending to the tips of notochaetae on segments 6, 8, and 13 ( Fig. 3A ).

Two pairs of short (shorter than length of one segment), cylindrical, ventral papillae present on segments 11 and 12 in holotype ( Fig. 3B ), but absent from the paratype.

Etymology: The species is named after the type locality, Longqi vent field.

Distribution: The species is currently only found in Longqi vent field.

Remarks: It is not easy to distinguish Levensteiniella longqiensis sp. nov. from other described Levensteiniella species from incomplete specimens. However, two pairs of short (shorter than one segment), cylindrical, ventral papillae in the holotype of Levensteiniella longqiensis sp.nov. are distinct from both males and females of other congeners. Females in this genus have no ventral papillae, while males usually possess either two pairs (as in Levensteiniella kincaidi , Levensteiniella manusensis , Levensteiniella plicata , Levensteiniella pettiboneae sp. nov., Levensteiniella raisae Pettibone, 1989 , and Levensteiniella undomarginata Zhang et al., 2018 ) or only one pair (as in Levensteiniella iris Hourdez and Desbruyères, 2003 and Levensteiniella intermedia Pettibone, 1990 ) of long (approximately as long as three segments), ventral papillae ( Pettibone 1985a, 1989, 1990, Hourdez and Desbruyères 2000, 2003, Wu and Xu 2018, Zhang et al. 2018b). However, additional intact specimens of Levensteiniella longqiensis sp. nov. are still needed to perform a more comprehensive comparison with its congeners. In addition, molecular DNA barcode analysis strongly supports Levensteiniella longqiensis sp. nov. to be a new species, indicating the importance of a molecular approach in separating deep-sea cryptic species ( Borda et al. 2013).

Figures

Figure 3. Levensteiniella longqiensis sp. nov. Holotype RSIO35287 in dorsal (A) and ventral views (B); head and anterior segments of paratype RSIO35289 in dorsal (C) and ventral views (D); E, anterior view of segment 9 on paratype RSIO35289; F, posterior view of segment 13 on holotype RSIO35287; G, notochaetae on segment 9 on paratype RSIO35289; H, neurochaetae of segment 13 on holotype RSIO35287. Scale bars:A, B = 1 mm, C = 0.25 mm, D = 0.2 mm, E = 0.5 mm, F = 250 μm, H = 25 μm.