Peinaleopolynoe mineoi Hatch & Rouse, 2020

Hatch, Avery S., Liew, Haebin, Hourdez, Stephane & Rouse, Greg W., 2020, Hungry scale worms Phylogenetics of Peinaleopolynoe (Polynoidae, Annelida), with four new species, ZooKeys 932, pp. 27-74 : 27

Peinaleopolynoe mineoi Hatch & Rouse sp. nov. Figures 7D , 10D , 16 , 17

Type locality.

Mound 12, Costa Rica (8°55.99'N, 84°18.45'W), ROV “SuBastian” Dive S0215, 1011 m depth, 8 January 2019.

Material examined.

Type specimen: Holotype (SIO-BIC A10071) on bones deployed at Mound 12, Costa Rica (8°55.99'N, 84°18.45'W), ROV “SuBastian” Dive S0215, 1011 m depth, 8 January 2019; fixed and preserved in 95% ethanol. Paratypes: One specimen (SIO-BIC A10070) from the same location as holotype; fixed and preserved in 95% ethanol. One specimen (SIO-BIC A9709) from on bones deployed at Mound 12, Costa Rica (8°55.8'N, 84°18.70'W), HOV “Alvin” Dive AD4974, 992 m depth, 20 October 2018; fixed and preserved in 95% ethanol. One specimen (MZUCR 1001-01) (SIO-BIC A9919) on a piece of decayed wood found at Mound 11, Costa Rica (8°55.33'N, 84°18.27'W), HOV “Alvin” Dive AD4988, 1010 m depth, 3 November 2018; fixed in formalin and preserved in 50% ethanol, with elytra fixed and preserved in 95% ethanol.

Description.

In life, large, overlapping, iridescent, semi-transparent elytra covering the dorsum. Dorsum with ciliated transverse bands extending onto bases of elytrophores and dorsal tubercles. Chaetae extending beyond the width of elytra (Fig. 7D ). Twenty-one segments total (Fig. 16A, B ). Elytra and elytrophores large, bulbous, nine pairs, on segments 2, 4, 5, 7, 9, 11, 13, 15, 17 (Fig. 16A ). Elytra sub-reniform, very thin, with several rounded broad macrotubercles along the posterior margin (Figs 7D , 16D ). Pharynx with seven dorsal border papillae and six ventral border papillae (Fig. 16C ). Bilobed prostomium with triangular anterior lobes bearing short, thin, very delicate lateral antennae (= minute frontal filaments, sensu Pettibone 1993). Smooth median antenna with bulbous ceratophore in anterior notch. Eyes lacking. Pair of thick, smooth, tapering palps (Fig. 16E ). Segment 1 with dorsal and ventral pairs of smooth, tapering anterior cirri (= tentacular cirri, sensu Pettibone 1993), approximately the same length as palps. Ventral anterior cirri slightly shorter than dorsal anterior cirri. Cirrophores of anterior cirri long and cylindrical, each with small acicular lobe on inner side (Fig. 16E, F ). Smooth ventral cirri on segments 2-21. Buccal cirri of segment 2 modified, with bulbous ceratophores and longer styles, ca. four times the length of remaining ventral cirri (Fig. 16F ). Buccal cirri attached to base of neuropodia. Ventral cirri on segments 3-21 attached to middle of neuropodia, with bulbous ceratophores and short, tapering styles (Fig. 16B, F ). Dorsal cirri present on non-elytrigerous segments 3, 6, 8, 10, 12, 14, 16, 18, 20, 21. Cirrophores of dorsal cirri cylindrical, rather long, fused to posterior sides of notopodia. Styles of dorsal cirri long, extending beyond length of chaetae. Segment 19 modified, lacking dorsal cirri and elytrophores (Fig. 16I ). Arborescent branchiae small with thin terminal filaments, beginning on segment 3 (Fig. 16E ) and continuing to segment 16 (Fig. 16I ). Branchiae forming single groups on elytrigerous segments, attached to bases of notopodia. Branchiae forming two groups on cirrigerous segments; small groups attached to dorsal tubercles and larger groups attached near bases of notopodia (Fig. 16G ). Four pairs of ventral segmental papillae on segments 12-15 (Fig. 16B ); medium length, curved laterally (Fig. 16H ). Pygidium with a pair of relatively short anal cirri (Fig. 16J ). Parapodia biramous. Neuropodia ca. twice the length of notopodia, with an acicular process. On cirrigerous segments, notopodia with dorsal tubercles possessing small bundles of branchiae (Fig. 17A, B ). Notopodia extending distally into acicular processes. Notochaetae forming radiating bundles, stout, with double rows of spines (Fig. 17C ). Notochaetae almost as long as neurochaetae. Neurochaetae slender, forming fan-shaped bundles (Fig. 17A, B ). Superior neurochaetae (supra-acicular) with double rows of spines and very slightly curved tips (Fig. 17D ). Inferior neurochaetae (sub-acicular) with double rows of teeth from the mid swelling to the hooked tips; smooth beneath the mid swelling (Fig. 17E ). Inferior neurochaetae teeth are less prominent than the superior neurochaetae spines. Hooked jaws with large, rounded, protruding teeth on inner borders (Fig. 10D ).

Morphological variation.

Holotype is 14 mm long, 7 mm wide, including chaetae. Paratypes range from 13-15 mm long, 5-7 mm wide, including chaetae.

Remarks.

Peinaleopolynoe mineoi sp. nov. is the sister taxon to the remaining Peinaleopolynoe spp. (Fig. 1 ) and like most of them has nine pairs of elytra and segment 19 lacking dorsal cirri and elytrophores (Table 5 ). Additionally, the four pairs of ventral papillae are tapering and curved laterally, as in all Peinaleopolynoe spp., excluding P. orphanae sp. nov. The angle of the ventral part of the neuroacicular lobe is nearly horizontal, distinct from P. goffrediae sp. nov. (Table 5 ). Peinaleopolynoe mineoi sp. nov. possesses several broadly rounded macrotubercles on the posterior margin of the elytra, quite distinct from the pointed macrotubercles found in P. santacatalina and P. goffrediae sp. nov., and the single, pointed macrotubercle found in P. elvisi sp. nov. (Table 5 ). Peinaleopolynoe mineoi sp. nov. is unique among Peinaleopolynoe taxa in having large, rounded, protruding teeth on the inner borders of their jaws.

Etymology.

Peinaleopolynoe mineoi sp. nov. is named after Ronald M. Mineo, MD, in recognition of support from the Mineo family, their interest in the deep sea, and support for our research.

Ecology.

Peinaleopolynoe mineoi sp. nov. was found associated with bones and wood (Table 5 ). Like P. santacatalina and P. orphanae sp. nov., it may be more of a habitat generalist than other Peinaleopolynoe .

Figures

Figure 1. Maximum likelihood (ML) tree of the combined analysis from six genes (COI, 16 S, 18 S, 28 S, H 3, CytB) aligned with MAFFT and then concatenated. Numbers next to nodes are ML bootstrap percentages from RAxML, Bayesian inference (BI) posterior probability, and maximum parsimony (MP) jackknife support values, separated by slashes. Key: * indicates 95 % bootstrap / jackknife or greater and 0.95 posterior probability or greater. - indicates the node was not found. Branchiae drawings at terminals indicate presence of arborescent or plicate branchiae; ~ indicates that on segments with two groups of branchiae, the position in T. branchiata is split into anterior and posterior groups, as opposed to upper and lower groups in remaining taxa. The seven paraphyletic groups of Branchinotogluma are highlighted in a yellow-orange gradient.

Figure 7. Live dorsal views of the new Peinaleopolynoe spp. A Peinaleopolynoe orphanae sp. nov. holotype SIO-BIC A 6151 B Peinaleopolynoe elvisi sp. nov. holotype SIO-BIC A 8488 C Peinaleopolynoe goffrediae sp. nov. holotype SIO-BIC A 5485 D Peinaleopolynoe mineoi sp. nov. holotype SIO-BIC A 10071. Scale bars: 6 mm (A); 8 mm (B, C); 1 mm (D).

Figure 10. Micrographs of Peinaleopolynoe spp. jaws A Peinaleopolynoe orphanae sp. nov. paratype SIO-BIC A 9996 B Peinaleopolynoe elvisi sp. nov. holotype SIO-BIC A 8488 C Peinaleopolynoe goffrediae sp. nov. holotype SIO-BIC A 5485 D Peinaleopolynoe mineoi sp. nov. paratype SIO-BIC A 9709. Scale bars: 3 mm (A, C); 2 mm (B, D).

Figure 16. Micrographs of P. mineoi sp. nov. holotype SIO-BIC A 10071 and paratype SIO-BIC A 9709 A dorsal view, holotype B ventral view, holotype. Segments 12 - 15 are marked to indicate the presence of four pairs of papillae C frontal view of proboscis showing papillae and jaws, paratype. Numbers mark the papillae on the dorsal (seven papillae) and ventral (six papillae) surfaces D loose elytron, holotype E dorsal view of anterior, holotype F ventral view of anterior, holotype G right side branchiae on segments 8 - 13, holotype H ventral papillae on segments 12 - 15 (four pairs) indicated by arrows, holotype I dorsal view of posterior, holotype J ventral view of posterior, holotype. Abbreviations: XII, segment 12; XIII, segment 13; XIV, segment 14; XV, segment 15; j, jaws; ma, median antenna; la, lateral antenna; pa, palp; dac, dorsal anterior cirrus; vac, ventral anterior cirrus; el, elytrophore; br, branchiae; nec, neurochaetae; noc, notochaetae; dc, dorsal cirrus; no, notopodium; vc, ventral cirrus; bc, buccal cirrus; ne, neuropodium; dt, dorsal tubercle; anc, anal cirrus. Scale bars: 1 mm (A, B, D); 0.5 mm (C, E-J).

Figure 17. Micrographs of P. mineoi sp. nov. holotype SIO-BIC A 10071 A right parapodium from segment 10 B right parapodium from segment 11 C notochaetae D superior neurochaetae (supra-acicular) E inferior neurochaetae (subacicular). Abbreviations: br 1, branchiae small group 1 attached to dorsal tubercle; br 2, branchiae large group 2 attached near base of notopodium; noc, notochaetae; dc, dorsal cirrus; no, notopodium; snec, superior neurochaetae; ne, neuropodium; neap, neuroacicular process; noap, notoacicular process; vc, ventral cirrus; inec, inferior neurochaetae; el, elytrophore; br, single large group of branchiae on elytrigerous segment. Scale bars: 0.5 mm (A, B); 15 μm (C); 5 μm (D, E).