Tectonatica pseudoprietoi, 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 : 170-172

Tectonatica pseudoprietoi sp. nov.

( Fig. 26 )

Type material. Holotype and 3 paratypes ( Table 9 ).

Type locality. Varovtsi , Ukraine .

Type stage. Middle Miocene (Upper Badenian) .

Etymology. From Greek ψευδηζ (pseudes) = false and prietoi = the name of the most closely similar species, i.e., Tectonatica prietoi .

Other material. Varovtsi: NP 10026 (2 shells); BD 166 (2 shells); MS 105 (2 shells).

Diagnosis. Globose shell with conical spire and inflated last whorl. Umbilicus a comma-like chink, wider adapically and gradually narrowing downward. Parietal callus thin, subrectangular, funicle low and broad; umbilical callus wide, thick in mid-abapical part of inner lip and with reverse S-shaped adaxial outline. Basal fasciole indistinct. Colour pattern of uneven, whitish to brown collabral lines over pale brown background.

Description. Protoconch small, depressed turbiniform, of 2.30−2.40 gently convex, apparently smooth whorls, tip very small. Teleoconch globose, thick. Spire conical, moderately elevated, whorls slightly convex, suture linear, adpressed. Last whorl inflated, rather depressed, slightly produced toward aperture; subsutural shelf indistinct, periphery above midline. Aperture D-shaped, in prosocline plane. Parietal callus subrectangular, moderately thin, ending at level of umbilical border, anterior lobe absent. Umbilicus a comma-like chink, wider adapically and gradually narrowing downward. Funicle broad and low, separated from umbilical wall by narrow spiral furrow. Umbilical callus rather thick, located at mid-abapical part of inner lip, bounded adaxially by reverse S-shaped outline and merging into parietal callus. Basal fasciole indistinct. Surface with rather dense, thin growth lines, stronger on subsutural shelf; microscopic spiral striation occurs on body whorl. Background colour uniform light brown, with pattern of uneven, whitish to brown collabral lines. No opercula found.

Remarks. Tectonatica pseudoprietoi sp. nov. is identical to the Pliocene to Recent (western Mediterranean and eastern Atlantic) species T. prietoi (Fig. 25.14−16) in teleoconch shape, but can be separated from it because of its protoconch with a smaller first half-whorl diameter (average values 0.094 mm and 0.120 mm, respectively) and its smaller overall size. Tectonatica pseudoprietoi sp. nov. is similar also to the late Miocene (Tortonian) to late Pliocene species T. astensis (Fig. 25.10−13), but it is readily differentiated from Sacco’s species in having: 1) a pro- toconch of about 0.5 fewer whorls, with a smaller diameter (average values 0.814 mm and 1.275 mm, respectively); and 2) a more widely open umbilicus. The values of the characteristic elements of the protoconch of T. anistratenkorum sp. nov. are basically identical to those measured for T. pseudoprietoi sp. nov.; however, T. anistratenkorum sp. nov. is readily differentiated from T. pseudoprietoi sp. nov. in having a more closed umbilicus and a greater width of the umbilical callus (see Fig. 19 ). Future recovering of specimens with the operculum filling the aperture will better clarify the relationships between these species.

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

Figures

FIGURE 26. Tectonatica pseudoprietoi sp. nov. from the middle Miocene (Upper Badenian) of Ukraine at Varovtsi. 1. Holotype, MPUM 11740; 2. Paratype 1, MZB 32147, teleoconch and protoconch; 3. Paratype 2, ZISP 1/62195; 4. Paratype 3, IGS NANU B-III-6/2018, protoconch.Arrows point to the protoconch-teleoconch transition. Scale bars: 10 mm, except protoconchs (figs 2b, 4: 500 µm).

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.

Tables

TABLE 9. Tectonatica pseudoprietoi sp. nov., type material, repository numbers and basic parameters. Spm stands for number of specimens; H stands for shell height (indicated as the maximum value if the paratype includes more than one shell)

type material	repository	locality	spm	material	H (mm)	figures
Holotype	MPUM 11740	Varovtsi	1	shell	8.82	26.1a–c
Paratype 1	MZB 32147	Varovtsi	1	shell	7.84	26.2a–b
Paratype 2	ZISP 1/62195	Varovtsi	1	shell	10.71	26.3a–b
Paratype 3	IGS NANU B-III-6/2018	Varovtsi	1	shell	5.82	26.4