Caberea cantabra, Reverter-Gil & Souto, 2023

Reverter-Gil, Oscar & Souto, Javier, 2023, New and non-indigenous species of Bryozoa from Iberian waters, European Journal of Taxonomy 885, pp. 33-64 : 52-55

Caberea cantabra sp. nov.

urn:lsid:zoobank.org:act:49867901-41D6-42DB-94AF-FF3129A57F37

Figs 10 , 12A ; Table 7

? Caberea boryi – Jullien 1882: 32.

Caberea boryi – d’Hondt 1973: 368–371 (part or whole); 1974: 3.

Differential diagnosis

Caberea with two oral spines in the outer distal angle, the outermost stouter, and one spine in the inner distal angle. Opesia obscured by a thick, oval scutum, its distal edge curved or irregular, hiding the operculum. Frontal avicularium monomorphic, small, with rounded mandible, present in almost all autozooids. Ovicell as long as wide, with an irregularly rounded fenestra of uncalcified ectooecium directly above the aperture.

Etymology

Alluding to the geographic origin of the studied material.

Material examined

Holotype ATLANTIC SPAIN • colony; Asturias; 43.71667° N, 06.08333° W; depth 342 m; 1 Aug. 2010; INDEMARES 0710 campaign; MHNUSC 10128 ( Fig. 10A–C, F–G ).

Paratypes ATLANTIC SPAIN • 2 colonies; Galicia; 44.01167° N, 07.11500° W; depth 490 m; 10 Aug. 1967; J.- L. d’Hondt leg.; MNHN-IB-2008-6926 ( Fig. 10D ) • 1 colony; Galicia; 44.02667° N, 07.03167° W; depth 510–630 m; 11 Aug. 1967; J.-L. d’Hondt leg.; MNHN-IB-2008-6935 ( Fig. 10E ) • 1 colony; Asturias; 43.93333° N, 05.73333° W; depth 400–690 m; 10 Oct. 1970; J.-L. d’Hondt leg.; MNHN-IB-2008-7078 .

Other material

Caberea boryi ( Audouin, 1826)

ATLANTIC SPAIN • several fragments of the same colony; Galicia, Ría of Ferrol ; 43.46470° N, 08.30441° W; depth 15 m; 23 May 2021; J. Souto leg.; MHNUSC-Bry 697 , 705 ( Fig. 11 ) .

Description

Colonies forming erect tufts up to 4 cm high. Branches straight, cylindrical, dividing dichotomously at regular intervals, without visible joints. Autozooids in two alternating longitudinal series, with frontal planes angled at about 120° to each other, defining the frontal surface of the branch. Autozooids elongated rectangular, with arched distal end. Opesia oval, constituting about three-quarters of total frontal length, bordered by broad, coarsely granular cryptocyst. Frontal proximal gymnocyst smooth. Two oral spines in the outer distal angle, the outermost stouter; one spine in the inner distal angle. All of them broken in the studied material. Central autozooid in a bifurcation with 4–5 spines. Ovicelled zooids with one spine in each angle. Almost all the opesia obscured by a thick, oval scutum, attached by a thick stalk one-half of the distance down the inner margin of the opesia. Its distal edge is curved or irregular, hiding the operculum; proximal part forming an ovate lobe. Outer edge of scutum does not cover the cryptocyst. Lateral avicularium very small, directly next to the outermost spine and difficult to see, with a rounded triangular mandible directed outwards. Frontal avicularium monomorphic, small, present in almost all autozooids, occupying part of the proximal gymnocyst just between the opesia and the stalk of the scutum of the proximal autozooid of the other series. Mandible small, rounded triangular, directed upwards. Ovicell as long as wide, recumbent on distally succeeding autozooid, occupying all its gymnocyst and hiding also the proximal cryptocyst; frontal avicularium of distal zooid displaced, united to distal inner angle of ooecium. An irregularly rounded fenestra of uncalcified ectooecium directly above the aperture. In ovicelled zooids the scutum tends to be slightly shorter, revealing part of the operculum. Abfrontal surface of colony covered by large, proximally tapered vibracula, with long and straight setal grooves, inclined to the branch axis; seta long, finely toothed along one edge. Setal groove of the central vibracula in the bifurcation shorter, located on the axis of the branch. Thin kenozooidal rhizoids arising from vibracular chambers, passing proximally along median abfrontal surface of each branch.

Remarks

The great majority of the species of Caberea are distributed around the Pacific Ocean ( Bock 2023). Only two species have been reported in European waters: the northern species Caberea ellisii ( Fleming, 1814) and the supposedly widespread Caberea boryi ( Audouin, 1826) . Caberea ellisii differs from C. cantabra sp. nov. most obviously by the lack of a scutum.

Although C. cantabra sp. nov. shows some similarities with C. boryi (it was previously reported under this name), both species clearly differ in several characters:

Autozooids are clearly smaller in C. boryi (0.37 × 0.23 mm according to Hayward & Ryland 1998). The scutum is completely different, being wider in C. cantabra sp. nov., projecting distally and covering the operculum ( Fig. 10A–C ), but lacking the projecting blunt process characteristic of C. boryi ( Fig. 11B– C ). Moreover, in this latter species the edge of the scutum is perfectly parallel to the edge of the opesia, leaving a fine separation ( Fig. 11B–C ), which does not occur in C. cantabra ( Fig. 10C ).

The cryptocyst is markedly granular in C. cantabra sp. nov. ( Fig. 10C–D ), whereas in C. boryi it is smooth ( Fig. 11B–C ).

The lateral avicularium is much smaller in C. cantabra sp. nov., almost inconspicuous and hidden by the base of a spine ( Fig. 10C–D ). Moreover, the large frontal avicularium that characterizes C. boryi ( Fig. 11C ) has not been observed.

The fenestra of the ovicell is large, about as long as wide ( Fig. 10D ), whilst in C. boryi the fenestra is clearly wider than long and usually has a wide calcified rim on the proximal edge ( Fig. 11B–C ).

Finally, C. boryi seems to be a shallow-water species, ranging from the intertidal to 100 m depth as much ( Hayward & Ryland 1998), whilst the material here identified as C. cantabra sp. nov. comes from 342–690 m depth.

D’Hondt (1973) reported C. boryi from deep waters to the NW of the Iberian Peninsula.We have examined the only two samples stemming from this area held at the MNHN: MNHN-IB-2008-6926 (stn Thalassa T 503, 490 m depth), and MNHN-IB-2008-6935 (stn Thalassa T512, 510– 630 m depth). Both actually correspond to C. cantabra sp. nov. (see material examined and Fig. 10D–E ). D’Hondt (1973) also reported C. boryi from a nearby locality (stn Thalassa 478, 513– 550 m depth), but no preserved material was found, so we cannot be certain about its identity, although it is very likely that it is also C. cantabra . Jullien (1882) also reported C. boryi from a nearby locality (Travailleur stn 39b, 1037 m depth), but the lack of reference material and additional data prevents us from verifying the identification. We have not been able to locate coordinates for the station 39b, not reported by Jullien (1882), whereas stations 39a and 40, also corresponding to the same date, are correctly referenced in Calvet (1907). For the purposes of representation on the map, we have used the coordinates of station 39a (corrected following Ryland 1969) because, in sharing numbering and a very similar depth (1000 m), we assume that they must be located very close together. D’Hondt (1973) also reported C. boryi from several localities in the NW of the Gulf of Biscay at 332–560 m depth, but again the lack of material, description and figures prevents us from verifying this record, which in any case should be considered doubtful due to the depth of the samples. Finally, C. cantabra was also reported by d’Hondt (1974, as C. boryi ) from off Cape Peñas (Asturias) at 400–690 m depth (stn Thalassa W405; MNHN-IB-2008-7078). Note that localities for each species were not included in this publication, and the only record of this species was taken by us from d’Hondt’s handwritten list. The locality is also included in the label of the sample. We have also revised a single sample from Avilés Canyon (Asturias) collected at 342 m depth (MHNUSC 10128) which is here designated as the holotype of C. cantabra sp. nov. (see Material examined and Fig. 10A–C, F–G ).

In summary, at present C. cantabra sp. nov. is known only from the north of the Iberian Peninsula, ranging from 342 to 690 m depth, and perhaps even deeper if the record in Jullien (1882 as C. boryi ) at 1037 m depth were of the same species ( Fig. 12A ).

Figures

Fig. 10. Caberea cantabra sp. nov. A–C, F–G. Holotype (MHNUSC 10128). A. Frontal view of branching pattern. B. Branching pattern. C. Detail of autozooids. D. Paratype (MNHN-IB-2008-6926), ovicelled zooids. E. Paratype (MNHN-IB-2008-6935), basal vibracula. F. Basal view of branching pattern. G. Basal view with developed rhizoids.

Fig. 12. Iberian distribution of the species treated in the present paper (see legends in the figures). A. Arbopercula angulata (Levinsen, 1909) and Caberea cantabra sp. nov. B. Species of Hincksina Norman, 1903.

Fig. 11. Caberea boryi (Audouin, 1826) (MHNUSC-Bry 697), Ría of Ferrol (Galicia, NW Spain). A. A colony. B. Ovicelled zooids showing the scuta and the frontal and lateral avicularia. C. Frontal gigantic avicularium.