Rubyspira pescaprae, Souza & Passos & Shimabukuro & Sumida, 2021

Souza, Bruno H. M., Passos, Flávio D., Shimabukuro, Maurício & Sumida, Paulo Y. G., 2021, An integrative approach distinguishes three new species of Abyssochrysoidea (Mollusca: Caenogastropoda) associated with organic falls of the deep south-west Atlantic, Zoological Journal of the Linnean Society 191 : -

RUBYSPIRA PESCAPRAE SP. NOV.

( FIGS 5A–O, 6, 7A–C)

LSID: zoobank.org:act: 276AD8F9-303F-46CD-B3DC- E5F3ABB6ABC9.

Type locality: Off Rio de Janeiro, Brazil, 3285 m, 25°20’18”S, 39°38’28.3”W, on and around organic falls (whale bones and wood parcels) .

Holotype: ZUEC-GAS 7913 ( Fig. 5A, E, L), sta. RJ3300 (25°20’18”S, 39°38’28.3”W) off Rio de Janeiro State, Brazil – ‘BioSuOr Project’ coll., 23 May 2015, depth 3285 m. Measurements: shell height: 28.9 mm; shell width: 13.0 mm.

Paratypes: #1 ZUEC-GAS 7914 , sta. same as holotype (total of 23 specimens, three of them in Fig. 5B–C, F, M, N); #2 ZUEC-GAS 7915 , sta. ES1500 (21°27’00.5”S, 39°53’47.4”W) off Espírito Santo State, May 2015, depth 1491 m (two specimens, one of them in Fig. 5G, H); #3 ZUEC-GAS 7916 , sta. ES3300 (22°50’27.1”S, 38°24’58.8”W) off Espírito Santo State, May 2015, depth 3322 m (six specimens) ; #4 ZUEC-GAS 7917 , sta. SP1500 (25°53’38.4”S, 45°02’05.4”W) off São Paulo State, October 2014, depth 1508 m (11 specimens) ; #5 MZUSP 151714 , sta. same as holotype (8 specimens) ; #6 MNRJ 23581 , sta. same as holotype (six specimens) .

Other materials examined: c. 880 specimens stored at ColBIO (Coleção Biológica Prof. Edmundo F. Nonato) at IOUSP. Collected in all sites of the present study. 25º54’S, 45º01.8’W, 1508 m depth (SP1500), October 2014 , 21º27’S, 39º54’W, 1491 m depth ( ES1500 ) ; 22º50.4’S, 38º25.2’W, 3322 m depth ( ES3300 ) ; 25º20.4’S, 39º38.4’W, 3285 m depth ( RJ3300 ) ; 28º01.8’S, 43º31.8’W, 3358 m depth (SP3300), May / June 2015 .

Etymology: From pes (Latin), foot, and capra (Latin), goat. It refers to the similarity between the radular marginal teeth and a crowbar, which in Portuguese is called ‘ pé de cabra ’, ‘goat foot’. Used as a feminine adjective.

Diagnosis: Teleoconch tall, multispiral, with wellmarked, sulcate suture; surface creamy white, smooth except basally where it is covered by flat, shallow, spiral ridges; periostracum thin, translucent, forming fine spiral lines. Protoconch whitish, with 2.5 whorls, with a cancellate sculpture. Radula taenioglossate (formula 2 + 1 + C + 1 + 2), with a central tooth bearing a smooth, pointed cusp, two hook-like laterals bearing small rounded denticles, and marginal teeth slender and incurved, with blunt, bifid cusp like a crowbar.

Shell: Adult shell large, thick, tall, width about 45% of height; up to 28.9 mm in height and 13.0 mm in width (measurements of the holotype). Multispiral, with teleoconch formed by up to about seven whorls, each one with a slightly and uniformly rounded profile and delimited by a well-marked, shallow sulcate suture; body whorl about half of shell height ( Fig. 5A–C, E, F, L, M). Umbilicus closed. Surface creamy white, often corroded, smooth except basally where about 18 flat, shallow spiral ridges are present and partially covered by the preceding whorl. Periostracum thin, translucent, forming fine, spiral lines ( Fig. 5D). Aperture orthocline, nearly one-third of shell height in fully developed individuals( Fig.5A) (a half in smaller ones: Fig.5G–I,N), teardrop-shaped, with smooth lips, the outer thin, with a convex and uniformly rounded profile, vertical in position in its median portion; inner lip sinuous. Siphonal and anal canal absent. Apex often eroded, without the protoconch and first teleoconch whorls, sealed with a calcareous plug. Protoconch whitish ( Fig. 5G, H), with 2.5 whorls ( Fig. 5J), maximum diameter 0.54 mm, with a cancellate sculpture composed by both distinct, well-defined spiral and axial cords ( Fig. 5G–K), the former ones absent in the upper-third of each whorl ( Fig. 5K); transition between the proto- and teleoconch well defined ( Fig. 5J). Operculum horny, thin, yellowish brown, paucispiral, with distinct growth lines and nucleus 20–25% height, width two-thirds the height of the operculum ( Fig. 5O); small relative to the size of the aperture.

Radula: About 1.4 mm long; length five times as broad in adult specimens ( Figs. 6 A, B). Taenioglossate, formula 2 + 1 + C + 1 + 2 ( Fig. 6C). Central tooth with quadrate base and triangular, pointed cusp, smooth ( Fig. 6C, D). Lateral teeth narrower but longer than central, hook-like, with incurved cusp, bearing small rounded denticles in both edges ( Figs. 6C, D). Both marginal teeth with same size and shape, slender and incurved, with blunt, bifid cusp like a crowbar; small rounded denticles may be present ( Fig. 6E).

Soft parts: The head has a large, broad and flat snout bearing a ventro apical mouth and large cephalic tentacles without eye lobes ( Fig. 7A). The foot is relatively small as compared to the snout, and has a furrow separating an anterior propodium from the posterior metapodium ( Fig. 7A, B). The simple mantle edge bears one large pallial tentacle on the right side of the snout, and one smaller on the left corner of the mantle; in most specimens, these tentacles are strongly contracted ( Fig. 7B, C). Male aphallic.

Remarks: Specimens of R. pescaprae mostly resemble R. osteovora regarding the shell shape and radula. However, in the former, the spiral sculpture is smoother. Moreover, the marginal teeth of R. pescaprae have a crowbar-like distal end, while R. osteovora bears rounded, marginal teeth. Juvenile specimens of both R. pescaprae and R. elongata are easily confused; larger adult specimens are easily distinguished by the deeper suture and the more rounded profile of the adult shell whorls, characteristics that are only present in R. pescaprae . Traits of the larval shell, such as the numbers of whorls and strong axial and spiral sculpture, can possibly indicate a planktotrophic development, characteristic for other species of this genus.

Rubyspira brasiliensis and R. goffrediae have a more globose shell and so are distinguished from R. pescaprae , in which it is taller. As highlighted by Hasegawa et al. (2019), all the teeth of the radula of R. brasiliensis are smooth, and so distinct from the ones of R. pescaprae . The bifid cusp of the marginals is characteristic of R. pescaprae new species, being distinctive from all other Rubyspira species.

Intraspecific divergences were lower than 1% and around 2% for COI and 16S, respectively. The lowest interspecific COI divergence of R. pescaprae was against R. osteovora (4.8%) and the highest was with R. goffrediae (16%). Rubyspira pescaprae is also less distant to R. osteovora on 16S, with 2.9% divergence from each other, while the most distant is R. goffrediae (~10%) (Table 2).

Distribution: Only known from the studied area, the Brazilian south-eastern coast (south-west Atlantic); 1491 to 3358 m depth. This new species was abundant in all sites with different sizes and developmental stages, except in SP3300, where only four juvenile specimens where collected. Most animals were found

to observe a well-preserved protoconch, which is also shown in detail in apical (J) and lateral views (K). J, the protoconch can be observed as having about 2.5 whorls; the first whorl is eroded and then its cancellate sculpture is not preserved. O, operculum: external view in the upper left, and internal view in the other two. P, Q, the holotypes of Rubyspira elongata and Cordesia atlantica are showed in the scale as in A–C, E, F and L–N (the scale is shown below M). pr, protoconch; te, teleoconch.

,

study

this

in

analysis

phylogenetic

on

used

Abyssochrysoidea

superfamily

the

of

animals

between animals

COI

and

among

for

S

16

proximities

divergence closer

genetic indicates

GTR-corrected heatmap of

. cells

2

Table darker on whale bones (89.6%) but were also observed on wood parcels (8.8%) and inert material (1.6%).