Basyaylella, Zágoršek & Gordon, 2013

Zágoršek, Kamil & Gordon, Dennis P., 2013, Late Tortonian bryozoans from Mut Basin, Central Anatolian Plateau, southern Turkey, Acta Palaeontologica Polonica 58 (3), pp. 595-607 : 598-600

Genus Basyaylella nov.

Type species: Basyaylella elsae sp. nov.; see below.

Etymology: Alluding to the name of the Başyayla section.

Diagnosis.—Colony erect, rigid, branches with circular cross sections. Up to five rows of autozooecia around branch, abfrontal side without orifices, formed by dorsal sides of marginal rows of autozooecia. Autozooecia with areolar pores, frontal pseudopores and central nonporous area on frontal shield as viewed from exterior. Orifices circular with thick, wide but short peristome. Primary orifice without sinus, secondary orifice may have a pseudosinus. Avicularia adventitious, situated on proximal part of autozooecia, on frontal as well on abfrontal side of colony. Ovicell globular with perforated entooecium, deeply immersed in distal autozooecium, but not frontally pronounced. Kenozooecia present.

Remarks.—The frontal shield of Basyaylella is perhaps mixed

(umbonuloid and lepralioid), and therefore the family and even the superfamily relationships are uncertain. However, it may have affinities with some genera traditionally classified in the Stomachetosellidae . This family is itself somewhat hetero−

geneous and badly needs revising, and the type species of

Stomachetosella is an Oligocene fossil, but let us consider the potential candidate genera, each based on its type species:

– Stomachetosella crassicollis Canu and Bassler, 1917 , Early Oligocene, Mississippi, has erect bilamellar/flabellate fronds to subvincularian stems in which the zooids, opening on all sides, have a regularly perforated, pseudoporous lepralioid frontal shield. The orifice has a tapering rounded poster and condyles appear to be lacking. Ovicells are hyperstomial and porous, somewhat like the frontal shield, and there are no avicularia.

– Enoplostomella defixa Canu and Bassler, 1917 , Late Eocene–Early Oligocene, Alabama, has erect cylindrical stems with zooids opening all around. The frontal shield in frontal view appears more or less evenly pseudoporous. The orifice develops a thickened peristomial rim in which an avicularium is set on one side of the sinus. Ovicells are conspicuous, hyperstomial, and evenly porous, and a well−developed adventitious avicularium is set in the peristomial rim on one side of the orifice.

– Metrocrypta bucculenta Canu and Bassler, 1917 , Late Eocene, North Carolina, has dichotomously branching cylindrical stems with zooids opening all around. Zooids are more or less evenly pseudoporous and, with secondary calcification, the interzooidal boundaries become indishttp://dx.doi.org/10.4202/app.2011.0100

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tinct. Primary orifices are deeply concealed and described as “orbicular”, i.e., lacking a sinus; secondary (peristomial) orifices are more or less round and raised above the zooidal surface. Small adventitious avicularia are lacking but Canu and Bassler (1917) described a very large laterofrontal avicularium suborally that occupies much of the frontal wall. Definite ovicells have not been identified but rare large, round broken chambers distal to some orifices could be ovicell chambers, in which case they would be described as hyperstomial and prominent in life. – Ochetosella jacksonica Canu and Bassler, 1917 , Middle

Eocene, Alabama, to Late Eocene, Mississipi and southeastern USA, likewise has cylindrical branching stems but the frontal shield is non−pseudoporous, with only marginal areolar pores. Interzooidal boundaries are raised in young zooids but become indistinct in older zooids. There is a large laterofrontal avicularium suborally in some zooids .

Ovicells are subglobular, smooth−surfaced and recumbent. – Metradolium dissimile Canu and Bassler, 1917 , Late

Eocene, southeastern USA, has flattened bifurcating branches with parallel sides and zooids opening all around. The frontal shield is convex and evenly pseudoporous with indistinct zooidal boundaries. The primary orifice is deeply concealed and suborbicular; the secondary orifice tends to be wider than long and is rounded without a projecting peristomial rim. Adventitious oval avicularia may occur just proximal of the corners of the peristomial orifice, single or paired, with one typically larger than the other. The ovicell is concealed and opens into the peristome; it is visible externally as a bulge.

Of the above genera, Ochetosella can be quickly ruled out. Although some individual zooids in Basyaylella gen. nov. can resemble zooids of Ochetosella (see the distalmost zooids in Fig. 2G), the species has a mostly frontally porous shield, which is not the case in Ochetosella . In the type species of the other four genera zooids open on all faces of the stems and the frontal shields are externally evenly pseudoporous. In details of form and placement of avicularia and ovicells, these three genera do not appear close enough to our new species to include it in the scope of their characters. On the other hand, what is known about the characters of two of the species ascribed by Canu and Bassler (1917) to Enoplostomella invites comparison with this genus. Enoplostomella vallata and E. magniporosa have dichotomously branching stems with distinct frontal and abfrontal faces, with 3–4 longitudinal rows of zooids opening mostly frontally and two longitudinal rows of dorsal zooidal walls appearing abfrontally. The dorsal side is relatively coarsely perforated and the interzooidal boundary between the two longitudinal rows of zooids forms a distinctively sinuous line down the middle. In this regard, plate 89, fig. 18 of Canu and Bassler (1917) showing the abfrontal side of E. magniporosa greatly resembles the arrangement in our Fig. 2E. Canu and Bassler (1917) presented no illustrations of the zooidal interiors in E. vallata and E. magniporosa and there is thus no evidence that either of these species has a mixed frontal shield. Our species also lacks a peristomial avicularium, whereas it has relatively large interzooidal avicularia, lacking in E. vallata and E. magniporosa . On the other hand, ovicells in the latter two species are concealed by secondary calcification (except distally in young zooids in E. magniporosa ), just as in our species. The “apertura”, i.e., the primary orifice, in E. vallata is described as “semilunar with a straight proximal border” in E. vallata and suborbicular in E. magniporosa ; in our species the primary orifice lacks a sinus.

On balance, we conclude that our species differs significantly from the type species of Enoplostomella to warrant a new genus. On the other hand, it appears highly likely that E. vallata and E. magniporosa are not congeneric with Enoplostomella . We cannot say, without detailed examination of these species, if they may be included in Basyaylella .

Geographic and stratygraphic range.—Late Tortonian, Başyayla section