Catalanispira Ebbestad, Kotala, and Isakar

Ebbestad, Jan Ove R. & Cope, John C. W., 2021, A low diversity Sinuites gastropod community from the Floian, Early Ordovician, of South Wales, Acta Palaeontologica Polonica 66 (2), pp. 319-335 : 326

Genus Catalanispira Ebbestad, Kotala, and Isakar ,

2020a Type species: Catalanispira plattevillensis Ebbestad, Kotala, and Isakar, 2020a , by original designation, from the lower 2 m of the Mifflin Member of the Turinian (Sandbian, Sa2, Upper Ordovician) Platteville Formation ( Diplograptus foliaceous Biozone ) in northern Illinois, eastern USA.

Catalanispira prima sp. nov.

Fig. 5 .

Zoobank LSID: urn:lsid:zoobank.org:act:4E4A585F­9C0C­49BF­A2B7­467C8303733E

Etymology: From Latin primus, first; from its earliest record of the genus.

Type material: Holotype ( NMW 2017.15 G.67, Fig. 5B ), external mould of the dorsal side, and its external mould . Paratypes ( NMW 2017.15 G.68– 70, Fig. 5A, C, D ), internal moulds from the type locality .

Type locality: Dan­lan­y­Castell quarry, Carmarthen , Wales, UK .

Type horizon: Merlinia selwynii Trilobite Zone, Moridunian regional Stage (lower Floian Stage, Fl 1) .

Material.— Type material only.

Diagnosis.—Species of Catalanispira with 3–3.5 whorls, strong convexity of upper whorl surface and a pleural angle of ~90°.

Description.—Shell large, up to 20 mm across, trochiform with 3–3.5 barely overlapping whorls, where last whorl expands widely. Shell height is about 2/3 of shell width, with the pleural angle being near 90°. Upper whorl surface strongly but evenly convex and sharply rounded at periphery, giving incised sutures. Aperture tangential, elongate elliptical, with a steep umbilical side leading into funnel­like umbilicus. Shell thin with simple comarginal growth lines on a slightly irregular surface.

Remarks.—The holotype is an external mould of the dorsal side of the shell from which a silicon cast was made ( Fig. 5B ), and it demonstrate the large widely expanding shell, number of whorls, and trochiform shape. The convexity of the upper whorl surface is best seen in second largest specimen in Fig. 5A . None of the specimens preserve the base, but the deep funnel­like umbilicus is seen in a lateral view of specimen NMW 2017.15G.70 ( Fig. 5D ). Although the whorls are somewhat collapsed, most of the convexity is intact. In apertural view it is possible to see the external mould of the umbilical side of the last whorl, showing the narrow lenticular shape of the whorl and steep umbilical wall ( Fig. 5D 3 ). The tangential aperture would place the spire at a high angle of inclination, pointing only slightly abaperturally ( Fig. 5C ). The shell is thin and with simple growth lines ( Fig. 5D 1 , D 2 ). The slightly irregular upper surface is evident in the same specimen, which seems to be the least deformed exemplar. The remaining three specimens show an irregular upper surface with broad comarginal folds of variable prominence. However, this feature is interpreted as largely secondary and enhanced by deformation and compaction.

The new taxon is placed with Catalanispira recently described by Ebbestad et al. (2020a), known from the Sandbian, Late Ordovician C. plattevillensis Ebbestad, Kotala, and Isakar, 2020a , in the USA, and the Darriwilian, late Middle Ordovician C. reinwaldti ( Öpik, 1930) from Estonia, owing to the large low trochiform shell, narrow elliptical aperture, deep funnel­like umbilicus and simple ornamentation. It lacks the characteristic broad axe­shaped aperture of the Tremadocian–Floian Pelecyogyra Ebbestad and Lefebvre, 2015 , from Morocco and France, which is placed within the same subfamily as Catalanispira ( Ebbestad et al. 2020a, b). Pelecyogyra also has fewer whorls and a much greater expansion of the last whorl.

Besides being much older than the two other species of Catalanispira , the Llangynog taxon seems to have more whorls, a more pronounced trochiform shell and stronger convexity of the upper whorl surface. In terms of size, the Estonian C. reinwaldti is larger than C. prima while C. plattevillensis is smaller. The shell shape of the latter resembles that of the Welsh species, but it has fewer whorls.

Stratigraphic and geographic range.—Lower Ordovician (Floian) of Wales, Middle Ordovician (Dw3) of Estonia, and the Upper Ordovician (Sa2) of the USA.

Figures

Fig. 5. Onychochilid mimospiridan Catalanispira prima sp. nov. from the Floian, Lower Ordovician, Bolahaul Member of the Ogof Hên Formation, Dan­lan­y­Castell quarry, Wales, UK. A. NMW 2017.15G.68, internal mould, in dorsal (A1), dorsal oblique (A2), and lateral (A3) views. B. NMW 2017.15G.67, silicon cast of the holotype in dorsal (B1) and dorsal oblique (B2) views. C. NMW 2017.15G.69, internal mould, in dorsal (C1) and anterior (C2) views, the latter shows the apertural plane oriented parallel to bedding plane. D. NMW 2017.15G.70, internal mould, in dorsal (D1), lateral (D2), and apertural (D3) views, the last shows original shape of the conch, the umbilical wall is preserved in the last whorl (arrowed). Scale bars 5 mm.

Fig. 3. Sinuitid bellerophontid Sinuites ramseyensis (Hicks, 1873) from the Floian, Lower Ordovician Bolahaul Member of the Ogof Hên Formation, Danlan­y­Castell quarry, Wales, UK. A. NMW 2017.15G.3, deformed shell in left lateral (A1), posterior oblique (A2), and anterior oblique (A3) views. Note the twisted and compacted median sinus seen as a line inA1 and A3. B. NMW 2017.15G.4, anterolateral shield in right lateral view.C. NMW 2017.15G.5, large, slightly dorso­ventrally flattened specimen in left lateral (C1) and dorsal (C2) views, showing median anterior sinus well. D. NMW 2017.15G.6, natural cross section in ventral view, showing the shape of the whorls. E. NMW 2017.15G.7, specimen in left lateral view (E1), showing the external mould of the initial whorls and the internal mould of the last whorl; details of the ornamentation as seen on the external mould (E2). Scale bars 5 mm.

Fig. 1. A. Moridunian stratigraphy (after Fortey and Owens 1978). B–D. Simplified maps of Wales (B), the southeastern part of the country (C), and the area south of Carmarthen (D) showing the location of the study area and outcrop. E. Simplified geological map with position of the Dan­lan­y­Castell quarry (modified from Cope 1982).

Fig. 2. Carcassonellid tergomyan Carcassonnella cf. vizcainoi Horný and Peel, 1996 from the Floian, Lower Ordovician Bolahaul Member of the Ogof Hên Formation, Dan­lan­y­Castell quarry, Wales, UK. A. NMW 2017.15G.1, silicon cast, in lateral (A1), posterior oblique (A2), and ventral (A3) views. B. NMW 2017.15G.2, internal mould in lateral view. Scale bars 5 mm.