Bispira beatrizae, 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 : 7-12

Bispira beatrizae sp. nov.

urn:lsid:zoobank.org:act:20AB5CE4-B1BF-4C9B-8526-F39B055D880E

( Figs 1–4 , 39A–E )

Material examined. Type material. Holotype, ICML-EMU-14010: TALUD VIII, St. 11, BC, 24º54'24"N 110º25'36"W, 17 April 2005, 895– 920 m. Paratype, ICML-EMU-14011: TALUD XIV, St. 33, BS, 27º47'52"N 111º09'30"W, 11 April 2011, 319– 344 m, 1 specimen . Additional material. ICML-EMU-14012: TALUD XV, St. 1, BS, 23º18'40"N 111º19'37"W, 04 August 2012, 750– 850 m, 13 specimens ; ICML-EMU-14013: TALUD XV, St. 5D, BS, 23º16'58"N 110º20'42"W, 05 August 2012, 650– 665 m, 6 specimens ; ICML-EMU-14014: TALUD XV, St. 23, BC, 27º08'11"N 114º32'54"W, 01 August 2012, 681 m, 5 specimens .

Description. Body flattened dorsoventrally ( Figs 1A , 3E ). Trunk 16 mm long (17 mm), thorax 3.2 mm wide (2.2–3.8 mm); branchial crown 24 mm long (22–23 mm), longer than body length ( Figs 1B , 3A ), with 16 pairs of radioles (15–16 pairs). Thorax with eight chaetigers ( Fig. 1A, C, D ), abdomen with 42 chaetigers (40–41 chaetigers). Radiolar lobes slightly involuted ventrally, dorsal basal flanges absent ( Fig. 1E ). Radioles fused by a palmate membrane as long as the length of five thoracic chaetigers, radioles without flanges, radiolar eyes absent ( Fig. 3B–D ). Axial skeleton composed of eight skeletal cells at palmate membrane level, vacuolated cells distributed in four transversal rows of two cells each ( Fig. 3F–G ). Radiolar tips short, filiform ( Fig. 3B ), occupying the space of five pinnules width. Dorsal lips elongated, finger-like ( Fig. 2D–G ), without mid-rib radiolar appendages, flaccid ( Fig. 3H–I ), as long as four thoracic segments; ventral lips small, rounded, poorly developed. Ventral sacs small, about 1/4 the length of collar ventrally, out of crown, mostly covered by ventral lappets ( Fig. 2A, C ). Three–4 short pairs of undeveloped ventral radioles (not longer than dorsal lips) ( Fig. 2E ). Collar with whitish anterior margin throughout ( Fig. 1C–E ); lateral collar margins of even height, covering the junction of crown and thorax ( Fig. 1C ); dorsal collar margins not fused to faecal groove, separated dorsally by wide gap, anterior peristomial ring exposed dorsally, between collar margins ( Fig. 1E ); ventral collar margin incised, forming two small rounded, not overlapped ventral lappets ( Figs 1D , 2A ). First segment slightly longer than following thoracic chaetigers, in ventral view; collar ventral shield (first chaetiger) with anterior margin distinct, W-shaped, followed by two teardrop shaped anterior marks, following thoracic shields rectangular ( Fig. 2A ); thoracic tori all separated from ventral shields ( Figs 1D , 2A ). Interramal eyespots absent on thorax ( Fig. 1C ). Wide faecal groove on thorax ( Fig. 1E ), thin and narrow on abdomen, ventrally. A visible brown inverted V-shaped mark throughout thoracic epithelium of the faecal groove, from chaetigers 2 to 5 (seen in holotype and in some additional specimens) ( Fig. 1E ). Collar chaetae with long broadly hooded chaetae, with thin conspicuous limbation on both sides of the axis; chaetae of following thoracic segments in two groups, superior chaetae long, elongate narrowly hooded ( Fig. 39A ), with hood as wide as width of shaft, inferior chaetae in two tiers of shorter spine-like chaetae ( Figs 4A–E , 39B ). Neuropodia with uncini progressively smaller ventralwards; uncini with around 8–10 rows of teeth above main fang, all similar in size, occupying half of main fang length; well-developed breast, long neck and short handle of similar length to distance between main fang and breast ( Figs 4H , 39C ), slightly longer in ventralmost uncini; companion chaetae with distal teardrop shaped membranes ( Figs 4F , 39E ). Small black interramal eyespots present on abdomen, more conspicuous on posterior half of abdomen ( Fig. 2B , pointed with arrows).Abdominal neurochaetae arranged in C-shape ( Fig. 4J ), on elevated neuropodia; anterior abdominal neurochaetae narrowly hooded on anterior and posterior rows ( Fig. 4G, J ); posterior abdominal neurochaetae narrowly hooded on anterior rows, and modified, elongate, narrowly hooded on posterior rows. Abdominal uncini similar to thoracic ones ( Figs 4I , 39D ), with around eight rows of teeth above main fang and handle as long as distance between main fang and breast. Pygidium with median incision, and two sub-rounded lateral structures; dark small pygidial eyespots on both sides of pygidial lobes ( Fig. 2B ). Tube made of dark mud with thick inner layer of solidified amber mucus, difficult to tear off.

Etymology. The species name is derived after Beatriz Yáñez-Rivera, a very appreciated friend and colleague, in recognition of her participation during the cruises TALUD, as well as sorting and curating the polychaetes samples in the laboratory, after cruises. The species-group name is a noun in the genitive case ( ICZN 1999, Art. 31.1.2).

Remarks. Bispira is composed by 24 species ( Capa et al. 2021), five of these lack typical, paired, compound eyes along radioles: B. brunnea ( Treadwell, 1917) , B. oatesiana ( Benham, 1927) , B. porifera ( Grube, 1878) , B. secusoluta ( Hoagland, 1919) , and B. wireni ( Johansson, 1927) . Radiolar eyes are also presumably lacking in Bispira sp. nov. sensu Goffredi et al. (2020: fig. 4A–B), a peculiar species discovered in methane seeps from Jaco Scar, Costa Rica, at depths of 1,768 to 1,887 m ( Goffredi et al. 2020). Bispira sp. nov. sensu Goffredi et al. (2020) is the first sabellid known to live in chemosynthetic bacterial symbiosis, where strains of methanotrophic Methylococcales bacteria were embedded in the cuticle of the radioles. Bispira sp. nov. sensu Goffredi et al. (2020) has a long branchial crown but a description of other morphological features is not included in the original paper to properly compare it with Bispira beatrizae sp. nov.

Among the species without radiolar eyes, B. porifera is unique by the presence of peristomial and thoracic spongy cushions ( Knight-Jones & Perkins 1998; Tovar-Hernández et al. 2020), a feature absent in members of the other species (i.e., B. brunnea , B. oatesiana , B. secusulota , B. wireni , and B. beatrizae sp. nov.). Bispira brunnea is distinctive by having long, triangular, overlapping ventral lappets of collar, extending to the distal end of palmate membrane ( Knight-Jones & Perkins 1998; Tovar-Hernández & Pineda-Vera 2008; Dávila-Jiménez et al. 2017); in specimens of all the other species, ventral lappets are low and rounded. Bispira oatesiana , B. secusulota and B. wireni have radiolar flanges and interramal eyespots on thorax and abdomen; in individuals of B. beatrizae sp. nov., radiolar flanges are absent and interramal eyespots are present only on posterior part of the abdomen. Bispira oatesiana has a radiolar skeleton composed of four vacuolated cells at the base, and those animals were found between 80–90 m deep; six vacuolated cells in B. secusulota , 290 m deep; and eight cells in B. wireni , originally described from 150–300 m deep, and then reported to 1,335 m deep, in a hydrothermal vent ( Knight-Jones & Perkins 1998; Capa et al. 2013a).

Bispira beatrizae sp. nov., and B. wireni radioles both have the axial skeleton composed of eight skeletal cells at the zone of palmate membrane, but the cellular arrangements is opposite: in B. beatrizae sp. nov., vacuolated cells are distributed in four transversal rows of two cells each, versus two transverse rows of four cells each in B. wireni . Other differences between members of these species are the following: 1. Ventral sacs are small, about 1/4 of the length of collar ventral in B. beatrizae sp. nov., versus ventral sacs long in B. wireni (exceeding the length of collar ventrally); 2. Dorsal lips elongated, flaccid, finger-like, without mid-rib radiolar appendages, as long as the length of four thoracic segments, in specimens of B. beatrizae sp. nov., versus dorsal lips triangular, with radiolar appendages, about the length of two thoracic segments in B. wireni ; 3. Radiolar flanges absent in individuals of B. beatrizae sp. nov., versus present, broad in B. wireni ; 4. In members of B. beatrizae sp. nov., the branchial crown is remarkably longer than the body length versus as long as body in B. wireni ; 5. Interramal eyespots are present only on posterior abdomen in specimens of B. beatrizae sp. nov., versus present on thorax and abdomen in B. wireni .

No species of Bispira has been described with flaccid, finger-like dorsal lips, similar to those present in B. beatrizae sp. nov., lacking the mid-rib radiolar appendage support. Bispira beatrizae sp. nov., and another new species of Bispira were found in the same sample. A comparison between both species is included below.

Abiotic conditions. The specimens of B. beatrizae sp. nov., were collected from 319–920 m deep, under the following environmental conditions. Temperature: 5.00–10.4°C; salinity: 34.45–34.55; dissolved oxygen: 0.07– 0.20 ml O 2 /l; % MO: 5.15–10.03; sediments dominated by silt (46.6 to 82.9%) ( Table 1).

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

Figures

FIGURE 1. Bispira beatrizae sp. nov. A) Trunk, ventro-lateral view, B) body, lateral view, C) thorax, lateral view, D) same, ventral view, E) same, dorsal view. Abbreviation: 1, 2, 3—refers to the number of chaetiger. Scale bars: A, C–E) 3 mm, B) 4 mm. A–E: holotype ICML-EMU-14010.

FIGURE 2. Bispira beatrizae sp. nov. A) Ventral shields of collar and thorax, B) posterior abdomen and pygidium, dorso-lateral view, C) ventral sacs, D, F) dorsal lip of right radiolar lobe, E) dorsal lip of left radiolar lobe, G) peristomium and dorsal lip, left radiolar lobe removed. Abbreviations: dl—dorsal lip, vs—ventral sacs, vsc—ventral shield of collar, 1, 2, 3—refers to the number of chaetiger. Scale bars: A, C, G) 1 mm, B, D–F) 0.5 mm. Arrows in B points to the interramal, abdominal eyes. A–B: holotype, ICML-EMU-14010. C–G: ICML-EMU-14012.

FIGURE 3. Bispira beatrizae sp. nov. A) Branchial crown, B) radiolar tip (zone 1 from A), C–D) radiolar rachis from first third of radiolar length (zone 2 from A), E) thoracic transversal section at chaetiger 4, F–G) transversal section of radioles at base of right radiolar lobe (2 mm from the base), H) entire dorsal lip, I) zoom in zone 1 from H. Abbreviations: d—dorsum, bv—blood vessels, g—gut, v—ventrum. Scale bars:A) 3 mm, B–D) 0.15 mm, E, G) 1 mm, F) 2 mm, H) 0.2 mm, I) 0.2 mm.A–D: holotype ICML-EMU-14010; E–I: ICML-EMU-14012.

FIGURE 4. Bispira beatrizae sp. nov. A) Thoracic chaetiger, B–C) superior notochaetae elongate narrowly hooded, D–E) inferior spine-like notochaetae, F) companion chaeta, G) abdominal chaetae narrowly hooded, H) thoracic uncini, I) abdominal uncini, J) abdominal chaetiger. Scale bars: A, J) 100 µm, B–E, G) 15 µm, F) 20 µm, H–I) 2.5 µm. A–J: holotype ICML-EMU- 14010.

FIGURE 39. Line drawings of chaetae and uncini. A–B, F–G, K, Q, T–U, X) Thoracic chaetae. C, H, L, R, W, Z) Thoracic uncini. D, I, N–O, S, V, Z1) Abdominal uncini. E) Companion chaeta. J) Abdominal chaeta. M, Y) Bayonet chaetae. A–E) Bispira beatrizae sp. nov. F–J) Bispira nunezi sp. nov. K–P) Chone tamai sp. nov. Q–S) Claviramus villalobosi sp. nov. T–W) Euchone nmercedesae sp. nov. X–Z1) Jasmineira agustinae sp. nov. Scale bar: 30 μm.