Turbo hartungi Bronn, 1861

Sacchetti, Claudia, Landau, Bernard & Ávila, Sérgio P., 2023, The Lower Pliocene marine gastropods of Santa Maria Island, Azores: Taxonomy and palaeobiogeographic implications, Zootaxa 5295 (1), pp. 1-150 : 26-27

Turbo hartungi Bronn, 1861

Plate 1 D 1 -D 5

* Trochus Hartungi Bronn in Hartung 1861: 118, figs. 1 a-c.

Trochus Hartungi Br. in Hrtg.—Bronn in Reiss 1862: 32.

Turbo Hartungi Bronn — Mayer 1864: 60, pl. 6, fig. 39.

Type material. Single specimen height 25.0 mm, width 25.0 mm, Ponta dos Matos, Santa Maria Island, Azores; whereabouts unknown ( Beu 2017: 165) .

Santa Maria material examined. Maximum height 9.0 mm, width 8.0 mm. DBUA-F 1295-1 (1), Malbusca (east cave), Santa Maria Island, Azores, Touril Complex, Lower Pliocene.

Original description. “ Eine lose senkrecht durchgespaltene Steinerfüllte Schale ohne Mūndung, von der Form und Grösse unseres Turbo fimbriatus und des Trochus patulus , erstem von unten und letztem von oben ähnlich. Er ist 25 Mm. hoch und breit . Die Oberseite breit kegelförmig, spitz, mit seichter Naht und flachen Windungen. Der Querschnitt der inneren Höhle ist rundlich, etwas quer (in der Zeichnung (b) breiter, weil der Querbruch schief auf die Achse geht). Die Unterseite scheint wenig gewölbt; die Schale in der Nabelgegend sehr dick, theilweise in Folge der Auflagerung einer der oberen und inneren Seite des letzten Umgangs entsprechenden Schalen-Schicht auf die des vorletzten, wodurch auch der Nabel gänzlich verdeckt worden zu sein scheint. Der äussere Umfang der 5-6 Umgänge ist von oben nach unten breit abgerundet; die Höhe der Gewind-Seite verhält sich zu der der Nabel-Seite = 3:2. Letzte zeigt in der Nähe des Nabels eine seichte Spiralfurche, die eine glatte flache Nabel-schwiele einzufassen scheint; darum eine breite glatte und nur fein strahliggestreifte Spiralzone; dann ganz in der Nähe des äusseren Umfangs und auf der gewölbten Aussenfläche selbst 7 an Grösse abwechselnd etwas ungleiche rundliche Spiral-Reife (c), über welche auf der schief abfallenden Oberseite der Windung noch 7–8 andere folgen, die, gleich ihren etwas engeren Zwischen-räumen und gleich jenen vorigen, parallel zur Mündung schief gestreift sind. Nur oben nächst der Naht treten diese Streifen weiter aus einander und werden stärker; so dass die 2—3 obersten Spiral-Reife undeulich werden und ein wellig-knotiges Ansehen bekommen, so dass der Naht-Reif etwa 36 schiefe Knötchen auf der letzten Windung trägt. Der nächst vorhergehende Umgang des Gewindes zeigt unterhalb dieser welligen Spiralzone nur noch 3 einfache Reife [An almost vertically split stone-filled shell without aperture, of the shape and size of our Turbo fimbriatus and the Trochus patulus , similar to the former from below and the latter from above. It is 25 mm in height and width. The upper side broadly cone-shaped, pointed, with shallow suture and flat whorl. The cross-section of the inner cavity is roundish, somewhat transverse (in the drawing (b) wider, because the transverse fracture runs obliquely to the vertical axis). The underside seems to be slightly convex; the shell in the umbilical region is very thick, partly as a result of the accumulation of a shell layer corresponding to the upper and inner side of the last whorl on that of the penultimate one, whereby the umbilicus seems to have been completely covered. The periphery of the 5-6 whorls is broadly rounded throughout from top to bottom; the height of the whorls side relative to the umbilical side [height-width ratio] is = 3:2. The base shows a shallow spiral groove near the umbilicus, which seems to surround a smooth flat umbilical callus; leaving therefore a broad smooth and only finely spirally striate zone; then very close to the curved periphery 7 irregular spirals of alternating strength (c), above which 7-8 further spirals on the shoulder, which are like the previous spirals somewhat narrower than their interspaces and parallel to the aperture and obliquely striated. Only near the suture are the cords stronger and wider spaced; so that the 2-3 uppermost spirals become subobsolete and wavy-nodular, about 36 oblique nodules on the last whorl. The penultimate whorl bears only 3 simple spirals below the wavy spiral adjacent to the suture.]” (Bronn in Hartung 1861: 118).

Revised description. Shell small, turbiniform. Protoconch paucispiral, 1.5 flattened whorls. Teleoconch of five whorls, first two whorls flattened to shoulder, shoulder sharply angled, straight below to suture. Shoulder bearing small open spines. Third whorl subsutural ramp becoming increasingly convex, portion below shoulder covered by succeeding whorl. Suture relatively deep, undulating around shoulder spines. Sculpture of rounded cords of slightly irregular strength interrupted by close set strongly prosocline growth lines weakly beading some of the cords, two subsutural cords strongly beaded. Last whorl slightly concave in subsutural area strongly convex mid-whorl, flattened at base, imperforate. Spiral sculpture on last whorl not persisting onto base. Aperture rounded, peristome complete, outer lip simple, columella roundly excavated, columella callus thickened, completely closing umbilicus.

Intraspecific variability. Only one specimen is at hand but fits relatively well with the original figure ( Bronn in Hartung 1861: figs. 1 a-c). The subsutural row of beads and base devoid of spiral cords is well illustrated (figs. 1 a-c). The whorls in the specimen at hand are possibly slightly more convex than in Bronn’s figures and the base of the outer lip less produced .

Discussion. Generic placement in the genus Turbo Linnaeus, 1758 is based on the flattened protoconch and earliest teleoconch whorl with spines produced at the shoulder, similar to that seen in the genus Bolma Risso, 1826 , but subsequent whorls are smooth and convex. A detailed molecular phylogeny of the Turbinidae is not yet available. However, the preliminary work by Williams & Ozawa (2006) showed that Turbo, in its widest sense, was not monophyletic. Today Turbo is a tropical Indo-Pacific genus. Neogene Atlantic and European records of Turbo are scarce. Turbo neuvillei Cossmann & Peyrot, 1917 from the Atlantic Lower Miocene Aquitanian of France is, in our opinion, a member of the genus Marmarostoma Swainson, 1829 , a genus which still occurs in the Caribbean today. Turbo saltus Olsson, 1922 from the Lower Pleistocene Moin Formation of Caribbean Costa Rica is a Taenioturbo Woodring, 1928 species. In the NHMW coll. (ex. Landau coll.) are specimens of an undescribed species of true Turbo from the Lower Pliocene Gurabo Formation of the Dominican Republic. Today, there are five species of Turbo reported in the Caribbean and Gulf of Mexico: Turbo angelvaldesi Ortea & Espinosa, 1996 (a species endemic to the Gulf of Mexico); Turbo cailletii P. Fischer & Bernardi, 1857 ; Turbo canaliculatus Hermann, 1781 ; Turbo castanea Gmelin, 1791 ; and Turbo haraldi Robertson, 1957 (endemic from the Caribbean). However, these are all sculptured and may be members of the genus Marmarostoma rather than Turbo. The validity of these genera in the extant species needs to be confirmed by molecular data before we can attempt to apply them to fossil forms. Therefore, if we consider Marmarostoma a synonym of Turbo, it was present in the Caribbean and mid-Atlantic islands in the Lower Pliocene and is still present today in the Caribbean. If Turbo is considered a separate genus from Marmarostoma , then true Turbo was present in the Caribbean and mid-Atlantic islands during the Lower Pliocene but does not occur in the Atlantic today. The presence of Turbo in the Azores suggests tropical water temperatures.

Distribution. Lower Pliocene: Atlantic, Santa Maria, Azores (Bronn in Hartung 1861; Bronn in Reiss 1862; Mayer 1864).

Figures

PLATE 1. A. Danilia pterostomus (Bronn, 1861), height 5.0 mm, width 4.0 mm, Forno da Cré (figure taken from Bronn in Hartung, 1861, pl. 19, fig. 2). B1-B2. Emarginula octaviana Coen, 1939, DBUA-F 487-1, height 1.8 mm, diameter 3.0 mm, Ponta do Castelo. C. Bolma cf. rugosa (Linné, 1767), DBUA-F 471-3, diameter 4.1 mm, Ponta do Castelo. D1-D5. Turbo hartungi Bronn 1861, DBUA-F 1295-1, height 9.0 mm, width 8.0 mm, Malbusca (east cave). E1-E3. Nerita cf. funata Dujardin, 1837, DBUA-F 917-1, height 4.0 mm, width 6.0 mm, Ponta do Castelo. F1-F2. Thericium crenulosum (Bronn, 1862), height 10.0 mm, width 6.0 mm, Ponta do Norte lighthouse, LNEG collection (unnumbered). G1-G2. Thericium hartungi (Mayer, 1862), height 29.0 mm, width 13.0 mm, Pinheiros (figure taken from Bronn in Reiss, 1862, pl. 1, fig. 11). H1-H2. Thericium incultum (Mayer, 1862), DBUA-F 1034-2, height 23.0 mm, width 10.0 mm, Macela viewpoint. I1-I2. Thericium incultum (Mayer, 1862), DBUA-F 1027-1, height 29.0 mm, width 11.0 mm, Malbusca II. J1-J2, K1-K2. Bittium miradouroense nov. sp., Holotype DBUAF 1034-5, height 6.8 mm, width 1.9 mm (J); Paratype DBUA-F 1034-6(1), height 5.3 mm, width 1.9 mm (K), Macela viewpoint. L1-L2, M1-M2. Bittium nov. sp., DBUA-F 488-2, height 4.5 mm, width 1.8 mm (L), height 4.2 mm, width 1.7 mm (M), Ponta do Castelo.

PLATE 5. A1-A2. Tritia atlantica (Mayer, 1862), DBUA-F 1295-2, height 13.0 mm, width 6.5 mm, Malbusca (east cave). B1-B2 C1-C2. Tritia serraticosta (Ĥrnes, 1852), DBUA-F 1292-A, height 6.2 mm, width 4.1 mm (B); height 8.1 mm, width 4.2 mm (C), Macela viewpoint. D. Tritia vetulum (Mayer, 1862), height 12.0 mm, width 6.0 mm, Pinheiros (figure taken from Bronn in Reiss, 1862, pl. 1, fig. 5). E1-E2. Aplus sp., height 7.5 mm, width 4.0 mm, Ponta do Castelo, LNEG collection (unnumbered). F1- F2. Orania cf. bellardiana (Foresti, 1884), DBUA-F 828-2, height 17.0 mm, width 12.0 mm, Ponta dos Frades. G1-G2. Favartia suboblonga (d’Orbigny, 1852), DBUA-F 946-3, height 19.0 mm, width 10.0 mm, Ponta dos Cedros. H1-H2. Bellardithala obsoleta (Brocchi, 1814), DBUA-F 542-4, height 5.9 mm, width 2.0 mm, Ponta dos Frades. I1-I2 J. Cancilla volvaria (Bronn, 1862), DBUA-F 937-2, height 10.9 mm, width 4.8 mm (I), Ponta do Castelo; height 15.5 mm, width 5.5 mm (J), Pinheiros (figure taken from Bronn in Reiss, 1862, pl. 1, fig. 4). K. Mitra (s.l.) peregrinula Mayer, 1864 species inquirenda, height 5.5 mm, width 2.5 mm, Feteirinhas (= Ponta das Salinas) (figure taken from Mayer, 1864, pl. 7, fig. 61). L1-L2. Mitra (s.l.) sp., DBUA-F 1295-3, height 12.9 mm, width 7.0 mm, Malbusca (east cave). M. Africonus trochilus (Mayer, 1864), length 16.0 mm, width 9.0 mm (incomplete spire fragment), Pinheiros, (figure taken from Mayer, 1864, pl. 7, fig. 60). N1-N2. Lautoconus cf. anomalomamillus (Sacco, 1893), DBUA-F 924-1, height 22.0 mm, width 11.0 mm, Malbusca. O. Plagioconus sp., height 35.5 mm, width 16.0 mm, unknown locality, LNEG collection (unnumbered). P1-P2 Q. Stephanoconus candidatus (Mayer, 1862), DBUA-F 913, diameter 19.0 mm (apical fragment of juvenile), Ponta dos Frades (P); diameter 40.0 mm, height 22.0 mm (incomplete spire fragment), Pinheiros (figure taken from Bronn in Reiss, pl. 1, fig. 1).