Chartella

Souto, Javier, Berning, Björn & Ostrovsky, Andrew N., 2016, Systematics and diversity of deep-water Cheilostomata (Bryozoa) from Galicia Bank (NE Atlantic), Zootaxa 4067 (4), pp. 401-459 : 413-414

? Chartella sp.

( Figs 23–27 , Table 7 )

Material examined. SMF 40.024, locality VH-97-315.

Description. Encrusting and very delicate colony, forming a small patch. Autozooids large, rhomboidal or hexagonal, vertical walls very thin and lightly calcified, interzooidal communication via several mural septula per zooid; basal walls only marginally calcified. Spines absent. Operculum small, having only a marginal sclerite. Avicularia small, interzooidal, situated between subsequent zooids in a row; cystid quadrangular, both, palatal foramen and posmandibular opesia are semicircular and separated by two small condyles, surrounded by narrow smooth cryptocyst; rostrum and mandible semicircular, directed distolaterally.

Ovicells and ancestrula not observed.

Remarks. Only one encrusting colony, consisting of about 20 zooids, is present in our material. Zooidal morphology resembles that of Chartella barleei ( Busk, 1860) , which is occasionally placed in the genus Terminoflustra , mainly owing to the position and morphology of the avicularia. However, usually only the erect part of the bilaminar branching colonies of C. barleei are described (e.g. Hayward & Ryland 1998; Kluge 1975) while virtually nothing is known about its encrusting portion. Prenant & Bobin (1966, p. 189) described it as a simple lamina similar to a membraniporid colony, which does not shed much light on the problem. We therefore only doubtfully assign this species to the genus Chartella .

When Álvarez (1992) described a similar encrusting species from shallow waters of the Strait of Gibraltar, he pointed out that there are some differences in zooid size of C. barleei from different regions. While Prenant & Bobin (1966) recorded relatively small zooids of around 0.4 mm in mean length from the Mediterranean Sea, Álvarez (1992) measured a mean of c. 0.6 mm in the Gibraltar specimens, whereas Hayward & Ryland (1998) reported a zooid size between 0.72 and 1 mm, which is identical to zooids of the present specimen.

Specimens from the Bay of Biscay, occurring between 340 and 630 m, were identified by d’Hondt (1973) as Terminoflustra aff. barleei . The only difference between these specimens and our material as well as C. barleei sensu stricto is the shape of the avicularia, which are more elliptical in the Bay of Biscay specimens. The zooid measurements from the erect colony part given by d’Hondt (1973) are similar to those from the Galicia Bank but no information about the encrusting portion was provided. Thus, in the light of these problems, and because only a single small specimen without ovicells was found, we have to leave the taxon in open nomenclature.

SD, standard deviation; N, number of measurements.

Figures

FIGURES 23 – 27.? Chartella sp. (SMF 40.012): 23, part of colony (light microscopy); 24, part of colony (SEM); 25, 27, autozooids and avicularia; 26, lateral wall with mural septula.

Tables

TABLE 7. Measurements (in mm) of? Chartella sp.

	Mean	SD	Minimum	Maximum	N
Autozooid length	0.884	0.0751	0.765	0.997	14
Autozooid width	0.678	0.0954	0.524	0.842	14
Avicularium cystid length	0.247	0.0286	0.212	0.279	6
Avicularium cystid width	0.251	0.0422	0.190	0.305	6
Avicularium frontal area length	0.177	0.0189	0.162	0.210	6
Avicularium frontal area width	0.123	0.0254	0.106	0.173	6