Teresaspis Rosso, 2018

Rosso, A., Beuck, L., Vertino, A., Sanfilippo, R. & Freiwald, A., 2018, Cribrilinids (Bryozoa, Cheilostomata) associated with deep-water coral habitats at the Great Bahama Bank slope (NW Atlantic), with description of new taxa, Zootaxa 4524 (4), pp. 401-439 : 419-421

Genus Teresaspis Rosso n. gen.

Type species. Cribrilina lineata Canu & Bassler, 1928

Diagnosis. Colony encrusting, uniserial, branching, forming wide irregular networks. Zooids elongate, clubshaped and slightly caudate, exposing an extensive gymnocyst and a frontal shield formed by flattened costae, each bearing a few pelmatidia, typically one at each costal base. Adjacent costae with only one intercostal bridge and a long intercostal space between neighbouring costae. Enlarged tips of opposite costae fused in the midline, leaving additional tiny pores. Orifice transversely subrectangular, with indistinct condyles. Two costal-like processes, cylindrical to flattened, located distally to the orifice, and two flattened placed laterally. All processes upward directed, those placed distally smaller than those placed laterally. Lateral processes typically arched, meeting above the orifice as the handle of a basket when completely developed. They become remarkably wider in the presence of ovicells. Ovicell hyperstomial, acleithral. Ooecium produced by the distal autozooid or occasionally by a kenozooid, smooth, with several pseudopores of variable shape and size. Avicularia absent. Kenozooids of two types: large with a costate shield and small with a tiny opesia. Ancestrula similar to autozooids but smaller.

Etymology. Composed of the Latin adjective teres, meaning tapered, and also well turned, and the Greek noun aspis, meaning shield. Feminine.

Remarks. This presently monospecific genus is introduced here to accommodate Cribrilina lineata Canu & Bassler, 1928 . This species cannot longer be included in the genus Cribrilina Gray, 1848 , neither in the subgenus Cribrilina sensu stricto as defined by Yang et al. (2018), with type species Lepralia punctata Hassall, 1841, nor in Juxtacribrilina Yang, Seo, Min, Grischenko & Gordon, 2018, with type species Cribrilina (Juxtacribrilina) flavomaris Yang, Seo, Min, Grischenko & Gordon, 2018 . The occurrence of the large prominent pseudoporous ooecium, and the absence of adventitious dwarf zooids among other characters, preclude its assignment to Juxtacribrilina. On the other hand, Cribrilina is not suitable because articulated oral spines and avicularia occur in that genus. Furthermore, following Bishop (1994), species of Cribrilina sensu lato exhibit little or no gymnocyst, lack apertural condyles, and often have a very strongly arched suboral bar, leaving a gap over the proximal border of the orifice. With some exceptions (e.g. C. macropuntata Winston, Hayward & Craig, 2000 ), pelmatidia on the costae are usually tiny in Cribrilina and missing on the gymnocyst at the base of costae.

Teresaspis Rosso n. gen. shares some characters with the genus Reginella Jullien, 1886 , such as the morphology of the orifice and ooecium, as well as the occurrence of paired, latero-oral processes, and a frontal shield of large costae with pelmatidia. However, an updated diagnosis of the genus is missing, and its revision is strongly needed because of the heterogenity of expressions of certain characters, e.g. presence or absence of avicularia and different ovicell morphologies, as already noticed by Cook (1985) and more recently by Taylor & McKinney (2006) (see also a discussion in Yang et al. 2018). Diagnoses and descriptions available for Reginella usually agree about the absence of lateral gymnocyst ( Yang et al. 2018), and the occurrence of several slit-like intercostal spaces arranged in strait rows across the zooids, often intersecting the mid-line without interruption ( Gordon 1984). This character was explicitly remarked by Jullien (1886) when erecting this genus, and described for the type species of the genus Cribrilaria furcata Hincks, 1882 , which also lacks avicularia ( Hincks 1882: 470). In contrast, Teresaspis Rosso n. gen. shows an extensive lateral gymnocyst, extending proximally to form a sort of short cauda and bearing a sub-elliptical row of pelmatidia, typically one at the base of each costa. Intercostal spaces never cross the midline but are restricted to one or the other side. Most furrows characteristically include a peripheral long intercostal space plus a centrally placed circular one. In contrast, it could be remarked that numerous small intercostal spaces and intercostal connections occur in species presently assigned to Reginella , although it has been demonstrated that the number of intercostal connections (and spaces) can vary within the same genus [e.g. in Pelmatopora Lang, 1916 , see Taylor & McKinney (2006)] and even within the same species (e.g. in Cribrilina mutabilis Ito, Onishi & Dick, 2015 , see Ito et al. (2015)]. Furthermore, the ovicell is only roughly similar, because a median suture occurs in Reginella that is absent in Teresaspis Rosso n. gen. Finally, no heterozooids have been reported in Reginella .

The frontal shield and ooecial morphology superficially resemble that of species belonging to Membraniporella Smitt, 1873 , and the encrusting phases of some species of Corbulipora MacGillivray, 1895 and Corbuliporina Vieira, Gordon, Souza & Haddad, 2010 . However, Membraniporella has avicularia, as do encrusting multiserial parts of colonies in both Corbulipora and Corbuliporina that, in addition, possess erect parts ( Bock & Cook 2001a; Vieira et al. 2010). Furthermore, in all these genera, autozooids expose only a narrow gymnocyst and have articulated oral spines ( De Blauwe 2009; Bock & Cook 2001a; Vieira et al. 2010). The frontal shield is also reminiscent of that of Gephyrotes moissettei Di Martino & Rosso, 2015 from the Miocene of Italy, and especially of G. spectabilis Canu & Bassler, 1920 from the Early Oligocene of Mississippi ( USA), which possesses costae fusing only along the zooid midline, leaving wide and long peripheral intercostal spaces. However, Gephyrotes has a different suboral costal complex (see below), tubular kenozooids located at zooidal margins, and usually also orificial avicularia ( Di Martino & Rosso 2015) that are completely missing in the present species. Also, the Cretaceous Aeolopora catillus Taylor & McKinney, 2006 exhibits a similar shield with a peripheral row of large and long intercostal spaces. However, in this species, also possessing ooecia with pseudopores and numerous avicularia, the costal shield occupies nearly the entire frontal surface ( Taylor & McKinney 2006).

Teresaspis Rosso n. gen. has some characters that could be considered as primitive per se and for their overall combination. However, some of them could result from a simplification, or an adaptation to particular environmental conditions. In Collarina Jullien, 1886 the occurrence of an extensive gymnocyst, inclined towards the substratum and clearly demarcated from the coastal shield, has been considered by Bishop (1994) as a character reminiscent of Cretaceous genera, such as Pelmatopora Lang, 1916 and Ichnopora Lang, 1916 , although it could result also from its secondary extension following a reduction of the costal shield. Analogously, the small number of intercostal spaces between adjacent costae could indicate a first step in the evolution of more advanced cribrimorphs from myagromorphs, a group considered as the representative of primitive cribrimorph by Larwood (1985) fide Lidgaard et al. (2012). Also, the uniserial colony architecture could be considered as a primitive feature. Some Cretaceous genera, such as Andriopora Lang, 1916 and Corymboporella Lang, 1917 , exclusively grow in uniserial rows and zooids may possess more or less elongated caudal portions ( Lang 1921; Larwood 1962). However, the uniserial growth pattern could also result from adaptation to the particular habitat and environmental conditions ( McKinney & Jackson 1989) and could have evolved multiple times among various cheilostome lineages ( Ostrovsky & Porter 2011, see also below).

A remarkable character of Teresaspis Rosso n. gen. is also the presence of a costal-like structure overarching the orifice, which develops on both sterile and ovicellate zooids, although it was first described by Canu & Bassler (1928) as restricted to ovicellate zooids in the type species. These authors compared this structure with that occasionally occurring in Cribrilina annulata var. spitzbergensis (now Reginella spitzbergensis , see Yang et al. 2018). However, in that species the latero-oral processes flank the ooecium proximally, nearly meeting but not overarching the zooidal orifice (see Bishop 1994: 235, fig. 33). Analogous structures of thickened oral costae arching on the ovicell and merging with each other to form a transversal ridge develop in several species assigned to Cribrilina sensu lato, including Cribrilina (Juxtacribrilina) annulata Fabricius, 1780 and Cribrilina corbicula ( O’Donoghue & O’Donoghue, 1923) (e.g. Bishop 1994; Dick et al. 2005; Young et al. 2018). Structures that really arch above the orifice, and are hence more comparable to those formed in the type species of Teresaspis Rosso n. gen. have been reported and/or figured in species of some cribrimorph genera. In many cases, however, these arched structures are formed by the thickening and superelevation of the first pair of costae proximal to the orifice, as it happens, among others, in Corbulipora inopinata Bock & Cook, 1998 and Anaskopora mesa Bock & Cook, 2001b (see Bock & Cook 1998 and Bock & Cook 2001b, respectively). Roughly similar but more complex orificial structures are formed by the first pair of costae, which bifurcate to produce distal branches that fuse above the orifice and with the adjacent proximal costae leaving one or more lacunae. This happens in species of Gephyrotes Norman, 1903 and in the unrelated genus Spiniflabellum Di Martino & Rosso, 2015 , both including fossil representatives, which go back to the late Eocene ( Di Martino & Rosso 2015) and the early Miocene ( Di Martino et al. 2017), respectively. However, the oral skeletal complexes in all these taxa are not entirely homologous, as do those formed in representatives of other fossil genera such as Tricephalopora Lang, 1916 and Morphasmopora Lang, 1916 , with or without the support of latero-oral avicularia and marginal kenozooids ( Taylor & McKinney 2006; Di Martino & Rosso 2015). In contrast, a proximal pair of non-articulated latero-oral processes comparable to those observed in the type species of Teresaspis Rosso n. gen., arched over the orifice occur in some other cribrimorph species, e.g. in the multiserial Collarina spicata Winston & Vieira, 2013 ( Winston & Vieira 2013, fig. 13B, D) and the encrusting phase of Corbulipora ornata MacGillivray, 1895 ( Bock & Cook 2001a, figs 1, 2). Further peristomial complexes have been described and roughly figured for a number of fossil, especially Cretaceous, species. Some of them were possibly formed by oral processes or the concurrence of oral processes and the first pair of costae, leading to the formation of more or less complicated configurations. Only oral processes seem to be involved in Ubaghsia arcifera Jullien, 1886 ( Jullien 1886, pl. 20, figs 2–4) and Batrachopora ranunculus Lang, 1916 ( Lang 1919, figs 33–35), whereas oral spines and first costae concur in species of Lagynopora Lang, 1916 , for instance in L. pustulosa Lang, 1916 and L. ampulla Lang, 1916 (see Larwood 1962, fig. 6p, q), as well as in Sandalopora levardinensis Lang, 1916 ( Lang 1919, figs 21–23) and “ Ubaghsia ” reticulata Ubaghs, 1865 ( Hillmer 1971, fig. 8). Most of these genera, however, also possess avicularia and kenozooids near the zooidal orifice. SEM examination of the specimens and possibly additional freshly collected material are needed to describe their real morphology and to confidently establish similarities between these taxa.

Distribution. Recent, north of Cuba and the GBBS.