Cochlis odovychenorum, Pedriali & Sosso & Dell’Angelo, 2019

Pedriali, Luca, Sosso, Maurizio & Dell’Angelo, Bruno, 2019, Naticid gastropods from the middle Miocene of western Ukraine, Zootaxa 4700 (2), pp. 151-195 : 162-166

Cochlis odovychenorum sp. nov.

(Fig. 23.1−13)

Type material. Holotype and 19 paratypes ( Table 3 ).

Type locality. Varovtsi , Ukraine .

Type stage. Middle Miocene (Upper Badenian) .

Etymology. The species is named after Nadiia Odovychena (wife of Bruno Dell’Angelo) and her children (Roman and Liudmyla) for the support provided during the field research in Ukraine.

Other material. Varovtsi: NP 10019 (56 shells); NP 10020 (2 opercula); MZB 50511 (1 operculum, Fig. 23.11a−b); MZB 50512 (1 operculum, Fig. 23.12); BD 159 (338 shells); BD 160 (26 opercula); MS 102 (8 shells). Horodok: NP 10017 (3 shells); NP 10018 (1 operculum); BD 161 (13 shells); BD 162 (2 opercula). Velyka Levada: NP 10021 (3 shells); BD 163 (5 shells). Zalistsi: NP 10031 (6 shells).

Diagnosis. Shell globose with low to moderately elevated spire and globose last whorl. Umbilicus deep, moderate to small. Parietal callus subrectangular; anterior lobe roundly angular, sometimes obsolescent. Funicle cord-like, broad and depressed; umbilical callus thick, roundly triangular, separated from anterior lobe of parietal callus by arched, shallow notch. Colour pattern of whitish to brown, uneven collabral lines over uniform light brown background. Operculum moderately thick, with two marginal grooves and two ridges. Outer groove narrow, inner groove a deeper and wider asymmetrical depression. Outer ridge thin, sharp; inner ridge massive, round to flat-topped, markedly wider than outer one.

Description. Protoconch small, low turbiniform, composed of 1.3 convex, smooth whorls, tip medium-sized. Teleoconch globose, thick. Spire broadly conical, low to moderately elevated, whorls convex; subsutural shelf flat on spire whorls, gently sloping on last one. Suture fine, adpressed. Last whorl globose, slightly expanded toward aperture. Aperture D-shaped, in slightly prosocline plane. Parietal callus subrectangular, thickened adapically, slightly narrowing abapically, with concave abapertural outline in most specimens. Anterior lobe roundly angular, sometimes obsolescent, especially in fully grown specimens, touching basal fasciole below level of umbilical border. Umbilicus deep, moderate to small, slit-like in a few young shells. Funicle cord-like, broad, markedly depressed, filling umbilicus to varying extent, separated from umbilical wall by shallow spiral furrow of variable breadth. Umbilical callus thick, located at abapical one-third of inner lip, roundly triangular, separated from anterior lobe of parietal callus by rounded, shallow notch, poorly defined in a few larger specimens. Basal fasciole broad, prominent, bounded abaxially by rounded step. Surface with rather dense growth lines, stronger on subsutural shelf and basal fasciole. A few specimens retain uniform pale brown background with pattern of whitish to brown, uneven collabral lines. Operculum moderately thick. Inner margin straight, with obscure transverse wrinkles; tubercles present in a few specimens. Inner surface flatly convex, nucleus scarcely protruding. Outer surface slightly concave at level of nucleus; central callus prominent to flat, tongue shaped, not reaching half-height of operculum. Marginal area gently sloping inward, with 2 marginal grooves and 2 ridges. Outer groove narrow, inner groove a deeper and wider asymmetrical depression. Outer ridge thin, sharp; inner ridge massive, round to flat-topped, markedly wider than outer one.

Remarks. Cochlis odovychenorum sp. nov. resembles Natica eximia , a species proposed by Eichwald (1830, p. 218), who published a concise diagnosis without figures: “ Testa ovato-rotundata, albo rufoque transversin fasciata, spira abbreviata, laterali, umbilico maximo, lato et profundo, submedio, apertura semicirculari; plerumque 6–10 lin., raro 1½ poll. longa ”. Eichwald based this new species on shells from various Ukraine collecting localities (Shukowze = Zhukivtsi; Bilka; Salisze = Zalistsi; Alt-Potschaiow = Staryi Pochaiv; Tarnaruda). Later, he confirmed the validity of the species and discussed the characters that distinguish N. eximia from some known species such as Natica millepunctata , N. glaucina , N. helicina , N. epiglottina and N. guilleminii Payraudeau, 1826 ( Eichwald 1840, p. 9). Finally, he published a good description with comments of one operculated specimen ( Eichwald 1853, p. 254), and included in the synonymy of N. eximia all the naticid species from Szuskowce (= Shushkivtsi) in Volhynia, figured by Du Bois de Montpéreux (1831, p. 44, pl. 2, figs 34, 35; pl. 3, figs 42−44). Eichwald (1859, pl. 10, fig. 42a−d) provided an excellent figure of an operculated shell of N. eximia , with no information on the collecting locality (he only mentioned “ espèce de Volhynie ” in the text). This specimen is very similar to one of those illustrated by Du Bois de Montpéreux (1831, pl. 3, figs 42, 43) and referred to as Natica glaucina Lin. , a nomen dubium ( Kabat 1990, pp. 21, 22).

We have not found specimens of N. eximia belonging to the type series, therefore it is really difficult to clarify the characters of this species; additional material is required to settle a decision in this respect. Anyhow, on the basis of the excellent figure published by Eichwald (1859), it appears that N. eximia differs from C. odovychenorum sp. nov. by having an operculum with two deeper and larger marginal grooves, a less elevated spire, a parietal callus without an anterior lobe, and a smaller overall size.

Pusch (1837, p. 100, pl. 9, fig. 14a−c) figured an operculated specimen from an unspecified Ukrainian locality referred to as Natica glaucinoides , an Eocene species, which is the type species of the genus Euspira ( Pastorino 2005; Pedriali & Robba 2009; Robba et al. 2016). On the basis of its teleoconch and opercular characters, this shell differs markedly from N. glaucinoides and belongs in the genus Cochlis . Pusch’s specimen has a teleoconch shape and operculum that are quite similar to those of C. odovychenorum sp. nov. and could be this species. However, not having examined the specimen, we include it in the synonymy of C. odovychenorum sp. nov. with reservation.

Cochlis odovychenorum sp. nov. is quite similar to the early−middle Miocene European species Cochlis tigrina (Figs 23.14−17) in teleoconch shape, but can be readily distinguished from it in having: 1) a protoconch with 0.5 more whorls, a greater diameter (average values 0.884 mm and 0.676 mm, respectively), and greater diameter of the first half-whorl (average values 0.323 mm and 0.164 mm, respectively); 2) a longer parietal callus with an anterior lobe (absent in C. tigrina ); 3) a more prominent basal fasciole; 4) a different colour pattern of uneven collabral lines (a reddish-brown pattern of dots and spots often forming collabral rows in C. tigrina ); and 5) a thinner and more concave operculum, with an elevated marginal area, gently sloping inward and incised by two narrower and shallower grooves.

Cochlis ukrainensis sp. nov. (see below) is easily distinguished from C. odovychenorum sp. nov. by having: a smaller size, a protoconch with smaller diameter of the first half-whorl (average values 0.195 mm and 0.323 mm, respectively), a less globose teleoconch, a smaller aperture width (see Fig. 13 ), a thinner and more prominent funicle, a narrower abapical sulcus (see Fig. 22 ), and a smaller umbilical callus (see Figs 18 , 21 ), separated from the anterior lobe of the parietal callus by a more angular deeper notch.

Cochlis odovychenorum sp. nov. is morphologically similar to the subspecies C. raropunctata obliquicallosa from the early Pliocene of Central Italy (Fig. 23.18−20), but its protoconch differs by having a greater diameter (with a value of 0.698 mm in C. raropunctata obliquicallosa ). In addition, C. odovychenorum sp. nov. is readily distinguished from C. raropunctata obliquicallosa in having: 1) a longer parietal callus (nearly twice the length), with distinct anterior lobe (indistinct in C. raropunctata obliquicallosa ); 2) a last whorl less expanded toward the aperture; 3) a smaller umbilicus; 4) a broader, more depressed funicle; 5) a different, less variable colour pattern of collabral lines (a reddish-brown pattern of dots, often arranged in collabral rows, spots and irregular spiral broken lines in C. raropunctata obliquicallosa ); and 6) a thinner operculum, with less elongate central callus, sloping inward marginal area (horizontal, lying upon the surface of the operculum in C. raropunctata obliquicallosa ) bearing two grooves and two ridges of different proportions.

Distribution. Middle Miocene: Central Paratethys (Upper Badenian) in Ukraine (this paper).

Figures

FIGURES 12–19. FIGURE 12. Relationship between the spire height and the shell height for species of Polinices Monfort, 1810 studied herein. FIGURE 13. Relationship between the aperture width and the aperture height for species of Cochlis Röding, 1798 studied herein. FIGURE 14. Relationship between the aperture width and the aperture height for species of Payraudeautia Bucquoy, Dautzenberg & Dolfuss, 1883 studied herein. FIGURE 15. Relationship between the aperture width and the maximum diameter for species of Payraudeautia Bucquoy, Dautzenberg & Dolfuss, 1883 studied herein. FIGURE 16. Relationship between the umbilicus width and the maximum diameter for species of Euspira Agassiz in J. Sowerby, 1837 studied herein. FIGURE 17. Relationship between the umbilicus width and the maximum diameter for species of Payraudeautia Bucquoy, Dautzenberg & Dolfuss, 1883 studied herein. FIGURE 18. Relationship between the width of the umbilical callus and the maximum diameter for species of Cochlis Röding, 1798 studied herein. FIGURE 19. Relationship between the width of the umbilical callus and the maximum diameter for species of Tectonatica Sacco, 1890 studied herein.

FIGURES 20–22. FIGURE 20. Relationship between the width of the umbilical callus and the maximum diameter for species of Payraudeautia Bucquoy, Dautzenberg & Dolfuss, 1883 studied herein. FIGURE 21. Relationship between the width of the umbilical callus and the umbilicus width for species of Cochlis Röding, 1798 studied herein. FIGURE 22. Relationship between the width of the abapical sulcus and the width of the adapical sulcus for species of Cochlis Röding, 1798 studied herein.