Paradoneis mackiei, León-González & Díaz-Castañeda & Hernández, 2025

Paradoneis mackiei sp. nov.

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Figures 5–7 View FIGURE 5 View FIGURE 6 View FIGURE 7

Type material

Holotype, (UANL-8182), GoogleMaps two paratypes (UANL-8183) Bahía de los Angeles , Baja California, Gulf of California , Station M4-2 , November 14 2013, N28.89650, W113.51538, 14 m depth. GoogleMaps

Additional material

11 specimens. 2 specimens, (UANL-8184) Los Angeles Bay, Baja California, Gulf of California, Station M1-2, November 14 2013, N28.90927, W113.48156, 18 m depth; 1 specimen, (UANL-8185), Station M1-4, N28.90927, W113.48156, 18 m depth; 3 specimens, (UANL-8186), Station M2-4, N28.90032, W113.48569, 17 m depth; 5 specimens, (UANL-8187), Station M3-1, N28.89534, W113.50281, 17 m depth.

Description

Holotype complete, 9 mm long (4.5–10 mm long in paratypes), 0.2 mm wide (0.15–0.2 mm wide in paratypes) with 84 chaetigers (83–89 chaetigers in paratypes). Color in ethanol pale yellowish. Body thin, cylindrical; significantly thicker at beginning of postbranchial region; gradually thinner towards posterior end. Prostomium subtriangular, slightly longer than wide, anterior end distinctly conical; eyespots present ( Fig. 7A View FIGURE 7 ). Nuchal organs elongated, located dorsally ( Fig. 7A View FIGURE 7 ). Two ciliated bands on the prostomium, dorsal one (ciliary slits) extended laterally, ventral one (crown like ciliary band) extended latero-dorsally without reaching the nuchal organs ( Fig. 5A–B View FIGURE 5 ). Peristomium fused with prostomium ventrally indistinct, starting point posterior to nuchal organs ( Fig. 7A–B View FIGURE 7 ), observed dorsally as a small fold overlapping posterior end of prostomium. Dorsal ciliary bands present on prebranchial segments, not seen posteriorly ( Fig. 5A View FIGURE 5 ).

Branchiae lanceolate, ciliated on the outer margin from the proximal part to near distal end on each branchia. Beginning from chaetiger 4, holotype with 9 pairs, paratypes 9–10 pairs. Branchial length variable along the body; branchiae overlapping dorsally on chaetigers 6 to 10 ( Figs 5A View FIGURE 5 , 6A View FIGURE 6 , 7A–B View FIGURE 7 ), slightly longer than body width, then becoming progressively shorter. Last pair of branchiae cirriform in shape ( Fig. 7B View FIGURE 7 ). Notopodial postchaetal lobes shorter and subtriangular with wide base on prebranchial chaetigers ( Figs 5A View FIGURE 5 , 7B–C View FIGURE 7 ), globular to subtriangular on branchial segments ( Figs 5A View FIGURE 5 , 6A–B View FIGURE 6 , 7D View FIGURE 7 ), becoming subtriangular and thinner slightly longer on postbranchial, median and posterior segments ( Figs 6C–D View FIGURE 6 , 7E–G View FIGURE 7 ), last eight notopodial prechaetal lobes (preanal region) progressively longer and thinner ( Fig. 6E View FIGURE 6 ). Notopodial postchaetal lobe easily detached and lost in many median and posterior chaetigers. Lateral sense organs visible from chaetiger 2, seen on pre- and branchial chaetigers as depression on ventral side of notopodial postchaetal lobes ( Fig. 6B View FIGURE 6 ). Neuropodial postchaetal lobes as low ridges, indistinct from body wall. Notopodial chaetae numbering 4–10 long capillaries in a tuft, reduced in number and length posteriorly, and 1–2 lyrated notochaetae from chaetigers 2. Lyrate notochaetae with tines of different size and thickness along body, each with an inner row of 7–8 spines, shorter branch slightly thicker, appears rigid, ending in a more or less blunt tip, the longer branch has a very thin and flexible distal part, ending in a point ( Fig. 5C View FIGURE 5 ); long tine 2.4 times longer than short tine on anterior chaetigers, 2 times longer on median and posterior chaetigers; short tine 1.2 to1.4 times thicker than long tine. Lyrated notochaetae increase in size from anterior to posterior parapodia: 17.2µm from the base of the chaeta to the distal end of the short tine in branchial parapodia, 18.8 µm in middle parapodia and 20.2 µm in posterior parapodia ( Fig. 7H–J View FIGURE 7 ). Neuropodial chaetae long capillaries in two rows, four capillaries on first neuropodium, 12–14 capillaries anteriorly, reduced to 4–8 posteriorly.

Pygidium oval, pygidial region with nine cirri, one pair corresponding to notopodial postchaetal lobes of a normal sized segment, two pairs corresponding to two preanal segments, migrate to ventral side, and three elongated anal cirri, two dorso-lateral and one mid-ventral, mid-ventral cirrus slightly thicker and shorter than lateral ones ( Fig. 6D–E View FIGURE 6 ).

Etymology

This species is named in honor of Andrew S.Y. Mackie, a great British polychaetologist who inspired the first author to study paraonid polychaetes.

Remarks

The genus Paradoneis is composed of 30 valid species including two subspecies: P. lyra capensis ( Day, 1955) and P. lyra guadalupensis (Amoreux, 1985) .

Paradoneis mackiei sp. nov., belongs to the group of Paradoneis species with three pre-branchial chaetigers, lyrate notochaetae and without modified neurochaetae. Other species that share these characteristics are Paradoneis lyra ( Southern, 1914) from Clare Island, Ireland, P. lyra capensis ( Day, 1955) from South Africa, P. forticirrata ( Strelzov, 1973) from Kuril Islands, P. nipponica Imajima, 1973 from Japan, P. ilvana Castelli, 1985 from Italy, P. lyra guadalupensis Amoreoux, 1985 from Guadeloupe Island, Antilles, P. brunnea ( Hartmann-Schröder & Rosenfeldt, 1988) from Antarctica, P. perdidoensis ( McLelland & Gaston, 1994) from Northwest Florida, Perdido Key, P. carmelitensis Arriaga-Hernández, Hernández-Alcántara & Solís-Weiss, 2013 from Terminos Lagoon, southern Gulf of Mexico, P. kamaehu Magalhães, Bailey-Brock & Barroso, 2018 from Mamala Bay, Oahu, Hawaii, P. campechensis Quintanar-Retama, Hernández-Alcántara & Solís-Weiss, 2019 from Campeche Sound, Mexico, P. heterochaeta Erdoğan-Dereli & Çinar, 2019 from Sea of Marmara, P. idoiae Martínez, 2019 from Abra de Bilbao, Spain, P. longifurcata Erdoğan-Dereli & Çinar, 2019 from Sea of Marmara, P. mexicanensis Quintanar-Retama, Hernández-Alcántara & Solís-Weiss, 2019 from Southern Gulf of Mexico and P. yucatanensis Quintanar-Retama, Hernández-Alcántara & Solís-Weiss, 2019 from Southern Gulf of Mexico.

Of these species, P. ilvana , P. heterochaeta , P. mexicanensis and P. nipponica , and P. mackiei sp. nov., have lyrate chaetae with tines of different thickness at least in part of the body, the rest of species have these kinds of chaetae with both tines of the same thickness. However, P. mackiei sp. nov. differs from them in terms of the following characters: (1) Lyrate notochaetae: the new species and P. nipponica present lyrate notochaetae with tines of different thickness along body, however, P. mackiei sp. nov. show a slight increase in size of lyrate chaetae from anterior to posterior end, this character is unknown for P. nipponica ; P. ilvana presents lyrate chaetae with tines of equal thickness in the anterior region, tines of different thickness in the posterior region; P. heterochaeta has lyrate chaetae with tines of equal thickness in the anterior region, while midbody and posterior chaetigers show the cooccurrence of chaetae with tines of both equal and unequal thickness in the posterior region; P. mexicanensis with two types of lyrate chaetae, on branchial region with distal end longer and thin with the short tine 3/4 the size of the long tine, longer than normal one in other species, in postbranchial region, with distal end shorter and stouter; in posterior chaetigers lyrate chaetae becoming thin again. (2) Prostomium shape: subtriangular, slightly longer than wide, anterior end distinctly conical in P. mackiei sp. nov.; triangular with anterior end weakly conical in P. ilvana ; triangular, with anterior end distinctly conical in P. heterochaeta ; conical, longer than wide in P. mexicanensis ; and a subtriangular lobe, little longer than wide in P. nipponica . (3) Notopodial postchaetal lobes: short and subtriangular with wide base in the prebranchial region, globular to subtriangular in the branchial region, becoming subtriangular and thinner slightly longer in the postbranchial region, last eight progressively longer and thinner in the preanal region in P. mackiei sp. nov.; short and cirriform in prebranchial region, indistinctly digitiform in branchial region, short and triangular in postbranchial region in P. heterochaeta ; short and rounded in prebranchial region, rudimentary in branchial region and long and triangular in postbranchial region in P. ilvana ; in first two chaetigers of prebranchial region short and rounded, digitiform and increase in length from chaetiger 3 throughout branchial region, small as cylindrical protuberance in postbranchial region, becoming longer at chaetigers before pygidium in P. mexicanensis ; short, digitate in prebranchial region, getting longer in branchial region, as small conical lobes in postbranchial region, filiform in preanal region in P. nipponica .