Perkinsiana araceliae, Tovar-Hernández & León-González & Hendrickx, 2025

Tovar-Hernández, María Ana, León-González, Jesús Angel De & Hendrickx, Michel E., 2025, Polychaeta collected during the research cruises TALUD aboard the R / V “ El Puma ” in the Mexican Pacific: Sabellidae and Serpulidae, Zootaxa 5663 (1), pp. 1-80 : 49-52

Perkinsiana araceliae sp. nov.

urn:lsid:zoobank.org:act:64144F42-6107-4B41-8898-D82EE4619B12

( Figs 26–27 , 40G–K )

Material examined. Type material. Holotype, ICML-EMU-14038: TALUD XV,St.23,BC, 27º08'11"N 114º32'54"W, 01 August 2012, 681 m. Paratypes, ICML-EMU-14039A and 14039B: same data as holotype. Paratypes, ICML- EMU-14040A and 14040B: same data as holotype. Additional material. ICML-EMU-14041: TALUD VIII, St. 11, BS, 24º54'24"N 110º25'36"W, 17 April 2005, 920 m, 3 specimens . ICML-EMU-14042: TALUD XV, St. 5D, BS, 23º16'58"N 110º20'42"W, 05 August, 2012, 671 m, 5 specimens .

Description. Body pale, flattened dorso-ventrally. Trunk 37 mm long (44 mm). Body 2.1 mm wide (2.2–2.5 mm). Branchial crown as long as 1/2 of the body length, 6.1 mm long under regeneration (22–34 mm) with 14 pairs of radioles (13–16). Thorax with eight chaetigers. Abdomen with 71 chaetigers (88 chaetigers). Radioles not fused by palmate membrane ( Fig. 26A ). Radiolar flanges absent ( Fig. 27C–D ). All radioles with short, digitiform tips, as long as the space of one pinnule ( Fig. 27C–D ). Longest pinnules at the last third of radiole ( Fig. 27C ). Collar margins not covering the bases of radioles ( Fig. 26A–D ). Dorsal collar margin not fused to faecal groove ( Fig. 26A, D ). Anterior peristomial ring exposed dorsally ( Fig. 26A, D ) and laterally ( Fig. 26C ). Ventral collar margin notched, forming two well developed ventral lappets, rounded, not overlapped ( Fig. 27B–E ). Parallel lamellae present, well developed ( Fig. 26E ). Ventral sacs absent. Dorsal lips as long as first three chaetigers (2 mm long), erect, triangular, long, with mid-rib and lateral lamellae, fused to dorsal pinnular appendages ( Fig. 27A–B ). Ventral lips small, rounded, folded ( Fig. 27A–B ). Ventral shield of collar divided in two transversal sections, the basal one broader than superior section, with all margins rounded ( Fig. 26B ). Interramal eyespots absent. Ventral shields well developed, all squared to rectangular ( Fig. 26B, E ). Thoracic tori occupy the entire distance between notopodia and ventral shield margins, contacting shields ( Fig. 27C, E ). Thoracic fascicles without developed broad notopodial lips and superior group of elongate, narrowly hooded chaetae ( Figs 27E , 40H ); and inferior group of paleate chaetae ( Figs 27F , 40G ), arranged in two rows. Thoracic uncini with crest surmounted by 8–9 rows of numerous minute teeth, handles 2x length of main fang ( Figs 27H , 40J ), not extending beyond the base of shaft of companion chaetae. Companion chaetae with tear-drop-shaped membranes ( Figs 27G , 40I ). Abdominal neurochaetae elongate narrowly-hooded chaetae ( Fig. 27J ). Chaetae from posterior abdomen twice longer than those in anterior abdomen. Abdominal uncini with main fang surmounted by 7–8 rows of numerous minute teeth, handles 1.5x length of main fang ( Figs 27I , 40K ). Pygidium rim-shaped ( Fig. 27F ), without eyes. Holotype with crown under regeneration, paratype D with ventral shield of collar under regeneration. Rigid tubes made of an inner thick layer of solidified amber mucus.

Etymology. This species is named after Araceli Jaquelin Mercado Santiago in recognition of her kind support curating samples included in this contribution, and her contribution to the study on spacial and bathymetric trends of polychaetes in the Gulf of California. The species-group name is a noun in the genitive case ( ICZN 1999, Art. 31.1.2).

Remarks. Perkinsiana is composed of 19 valid species ( Capa et al. 2021). There is no evidence of the genus being monophyletic ( Fitzhugh 1989, Capa 2007, Tovar-Hernández et al. 2012) but there is a need for a worldwide revision of the genus.

Six species of Perkinsiana were originally described from America: one from Puerto Rico ( P. fonticula ( Hoagland, 1919)) and the rest from Argentina and Chile. In Mexico only P. fonticula has been reported for some Caribbean localities of Quintana Roo state ( Tovar-Hernández & Salazar-Vallejo 2006). In the present study, two new species of Perkinsiana are present on the west coast of Baja California Peninsula, both were found together within the same stations and constitutes new records of the genus in Western Mexico.

Among the currently valid species of Perkinsiana , Perkinsiana araceliae sp. nov., P. brigittae Tovar-Hernández et al. 2012 , P. acuminata ( Moore & Bush, 1904) and P. minuta ( Treadwell, 1941) shares the presence of abdominal chaetae elongate, narrowly hooded (Type C sensu Tovar-Hernández et al. 2012). In P. acuminata the ventral lappets of collar overlap (not overlapped in all other species). The anterior peristomial ring is fully exposed dorso-laterally in Perkinsiana araceliae sp. nov., and P. brigittae , whereas it is not exposed in P. minuta . Perkinsiana brigittae have broad radiolar flanges but flanges are absent in Perkinsiana araceliae sp. nov.

Abiotic conditions. The specimens of P. araceliae sp. nov., were collected from 671‒920 m deep, under the following environmental conditions. Temperature: 5.00‒6.44°C; salinity: 34.45‒34.55; dissolved oxygen: 0.07‒ 0.20 ml O 2 /l; %MO: 5.15‒10.03; sediments dominated by sand and silt (46.6% each), silt (82.9%) or “mud” (71.1% of combined silt and clay) ( Table 1).

Distribution. South Gulf of California and west coast of Baja California Sur, Mexico.

Figures

FIGURE 26. Perkinsiana araceliae sp. nov. A, D) Thorax, dorsal view, B) same, ventral view, C) same, lateral view, D) collar, dorsal view, E) same, ventral view, F) posterior abdomen and pygidium.Abbreviations: d—dorsum, pl—parallel lamella, v—ventrum. Scale bars: A, D–F) 0.5 mm, B–C) 1 mm. All stained with methyl green. A–C, F) holotype ICML-EMU-14038, D–E) paratype ICML-EMU-14039A.

FIGURE 27. Perkinsiana araceliae sp. nov. A) Internal structures of branchial crown, B) detail of dorsal and ventral lips, C–D) radiolar tips pointed with arrows, E) superior thoracic chaetae narrowly hooded, F) inferior thoracic paleate chaetae, G) companion chaetae, H) thoracic uncini, I) abdominal uncinus, J) abdominal chaetiger with narrowly hooded chaetae. Abbreviations: d—dorsum, dl—dorsal lip, dpa—dorsal pinnular appendage, md—mid-rib, v—ventrum, vl—ventral lip. Scale bars: A–B) 1 mm, C) 0.4 mm, D) 0.2 mm, E, G) 20 μm, F) 25 μm, J–I) 40 μm, J) 100 μm.A–B) paratype ICML-EMU-14039A, C–J) holotype ICML-EMU-14038.

FIGURE 40. Line drawings of chaetae and uncini. A, G–H, L–M, S) Thoracic chaetae. B, E, J, O, Q, T) Thoracic uncini. C–D, F, K, P, U) Abdominal uncini. I, N, R) Companion chaetae. A–D) Myxicola bruscai sp. nov. E–F) Myxicola dilianae sp. nov. G–K) Perkinsiana araceliae sp. nov. L–P) Perkinsiana nuriae sp. nov. Q–U) Potamethus pepei sp. nov. Scale bar: 30 μm.