The Lower Pliocene marine gastropods of Santa Maria Island, Azores: Taxonomy and palaeobiogeographic implications Author Sacchetti, Claudia 0000-0002-3225-3139 claudiasacc@icloud.com Author Landau, Bernard 0000-0002-7768-8494 bernardmlandau@gmail.com Author Ávila, Sérgio P. 0000-0002-3225-3139 claudiasacc@icloud.com text Zootaxa 2023 2023-05-24 5295 1 1 150 http://dx.doi.org/10.11646/zootaxa.5295.1.1 journal article 53396 10.11646/zootaxa.5295.1.1 82286fdc-a858-447c-9980-da2e8985d19c 1175-5326 7965273 F3A52660-70B8-439F-A7A0-F45ADC975EA5 Mitra (s.l.) peregrinula Mayer, 1864 species inquirenda Plate 5 K * Mitra peregrinula Mayer 1864: 82 , pl. 7, fig. 61. Type material. Single specimen height 5.5 mm, width 2.5 mm, Feteirinhas (= Ponta das Salinas ), Santa Maria Island , Azores, Touril Complex , Lower Pliocene ; whereabouts unknown ( Beu 2017:165 ) . Original description. “ Trotz ihrem übeln Erhaltungszustande, glaube ich diese minutiöse Art doch als neu beschreiben zu müssen, da ihre Stellung eine ganz sichere ist und sie nur wenige Verwandte besitzt. Sie gehört nämlich zur kleinen Gruppe Conelix und steht einzig der M. conica ( C. conicus Swains. ) nahe, zeichnet sich aber durch ihre Kleinheit, ihre noch kürzere Gestalt und ihre gedrängteren Spiralfurchen davor aus. Ich fand sie, wie so viele andere interessante Arten, im Kalktuff der Feiteirinhas [Despite its bad state of preservation, I think I have to describe this minute species as a new species, since its position is quite secure, and it has only a few relatives. It belongs to the small group of Conelix and it is only close to M. conica ( C. conicus Swains. ), but is characterized by its small size, it is even shorter shape and its more crowded spiral grooves. I found it, like so many other interesting species, in the tuff of Feiteirinhas.]” ( Mayer 1864: 82 ). Latin description. “ Testa minuta , turbinato-conica-transversisulcata; spira acuta, medio valde producta, acutissima; anfractibus numerosis, angustissimis; ultimo basi attenuato; labro simplici; columella basi plicata .” ( Mayer 1864: 82 ). Discussion. The type specimen was illustrated from the dorsal side only and shows a juvenile shell with a strongly coeloconoid pointed spire and a totally conic last whorl. Moreover, Mayer’s 1864 Latin description says that the columella has a single fold at the base, whereas mitrid gastropods have numerous columellar folds. We are not sure how to identify this specimen, but it might represent a very juvenile cone shell. Distribution. Lower Pliocene: Atlantic, Santa Maria Island, Azores ( Mayer 1864 ). Mitra (s.l.) sp. Plate 5 L 1 -L 2 Santa Maria material examined. Maximum height 12.9 mm, width 7.0 mm. DBUA-F 1295-3 (1), Malbusca (east cave), Santa Maria Island, Azores , Touril Complex, Lower Pliocene. Revised description. Shell small to medium sized, relatively solid, spire missing. Penultimate whorl low, depressed, convex with periphery at abapical suture (low spire may in accentuated by wear), suture moderately impressed, linear. Last whorl somewhat globose, broadly rounded, moderately constricted at base, siphonal fasciole not delimited from base. Sculpture limited to a few weak cords over fasciole. Aperture elongate, very narrow adapically, widening slightly mid-aperture; anal sinus very narrow; siphonal canal moderate length, open, shallowly notched. Outer lip simple, not thickened by varix, weakly convex at extremities, flattened mid-aperture. Columella bearing narrow callus rim, abapical half thickened, bearing four prominent, oblique folds. Discussion. The columellar folds confirm taxonomic placement within the Mitridae . This species is represented by a single specimen with the apex missing and the last whorl abraded. We aren’t sure that the penultimate whorl is a low and rounded as it seems or this is a result of wear. If not due to wear, the species would have a very low spire. The last whorl is also unusually globose and constricted at the base compared to other mitrids. We await further material to better characterised this species. Distribution. Lower Pliocene: Atlantic, Santa Maria Island, Azores (this paper).