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Hemiconus arpadzsoldosi (Kovacs et al., 2026)
Etymology
Named after Árpád Zsoldos, father of Márton Zsoldos Hungarian shell collector and illustrator, who collected the type specimen.
Diagnosis
Hemiconus species with biconical shell, moderately elevated spire, 7 teleoconch whorls. Slightly gradate spire, weakly tuberculate subsutural band, concave ramp, angulate shoulder, parallel-sided aperture. Spiral sculpture of rounded suprasutural tubercles, 3 beaded spiral cords on subsutural ramp, broad, low, flat cords on upper half of last whorl, narrower on lower half, base with strong ridges. Fine growth lines, shallow, asymmetrically curved subsutural flexure.
Description
Biconical shell with moderately elevated spire, protoconch not preserved, teleoconch of 7 whorls. Spire conical with slightly gradate outline, spire angle 65°. Whorls with weakly tuberculate subsutural band, concave ramp, angulate shoulder, narrow, undulating suture. Last whorl 82% of total height, with slightly sigmoid outline being somewhat convex below shoulder, slightly concave at lower third. Aperture moderately wide, straigth, parallel-sided, filled with sediment, outer lip thin. Spiral sculpture of welldeveloped, closely spaced, rounded suprasutural tubercles on early teleoconch whorls, becoming sharper on penultimate whorl (15 tubercles), and much weaker on last whorl forming sharp shoulder, 3 beaded spiral cords on subsutural ramp, fine striae below subsutural band. Last whorl bearing numerous broad, low, flat cords on upper half separated by narrow, deep grooves, cords becoming irregularly narrower on lower half, base covered by strong ridges. Axial sculpture of fine growth lines, subsutural flexure shallow, asymmetrically curved.
Remarks
Considering its size and overall morphology, the new species is assigned to genus Hemiconus as a representative of the H. tremletti group (see Tracey et al. 2017). Hemiconus arpadzsoldosi sp. nov. is similar to H. tremletti Le Renard, 1994 (Lutetian, France) in its shell shape and spire sculpture (this is not true: in Hemiconus tremlettii the sculpture of the last whorl is formed by raised lines, while in H. arpadzsoldosi it is formed by incised grooves separated by large spaces) but differs by its larger size and bearing broad and flat spiral cords on last whorl (see Tracey et al. 2017, text-fig. 16, pl. 6, figs 80–84, pl. 9, fig. 123).
Hemiconus pissarroi Tracey & Craig, 2017 is a smaller form with slightly concave spire outline, its last whorl is not constricted at base, and it bears weaker tubercles and narrow spiral cords on last whorl (Tracey et al. 2017, text-fig. 15, pl. 1, figs 76–79).
Hemiconus bicoronatus (Melleville, 1843) (Ypresian, France) has larger tubercles overriding by spiral threads and its shell is covered by strong, narrow spiral cords (Pacaud 2016, figs 1–5),
while H. rouaulti (d’Archiac, 1850) (Ypresian, France) which is characterized by similar sigmoid outline of the last whorl, bears less developed tubercles on its spire and narrower spiral cords on last whorl (Tracey et al. 2017, pl. 1, fig. 4).
Upper half of the last whorls of both Hemiconus filifer (Edwards, 1857) (Lutetian, England) and H. parisiensis (Deshayes, 1865) (Lutetian, France) are smooth (Tracey et al. 2017, pl. 1, figs 5–6).
Hemiconus concinnus (J. Sowerby, 1821) (Ypresian, England) bears similar broad spiral cords on last whorl but its spire is higher, and it has stronger ornamentation on spire whorls (Janssen et al. 2014, fig. 12; Pacaud 2016, fig. 6; Tracey et al. 2017, pl. 1, fig. 3).
Considering the neighboring regions, in the Alpine Tethys Hemiconus peterlini (De Gregorio, 1880) (Lutetian, N Italy) is a moderately larger form (SL 38 mm) with slightly concave spire outline, and its sculpture consisting of much weaker tubercles on spire whorls, and alternating strong primary and secondary cords on last whorl (De Gregorio 1880: 70, pl. 7, fig. 32).
From the Ukrainian Archipelago numerous conid species were recorded by Klushnikov (1958), Zelinskaya et al. (1968) and Amitrov (2018). The specimens described as Conus plicatilis by the first two authors display somewhat similar shell proportion to that of Hemiconus arpadzsoldosi sp. nov. but differ by higher spire and much reduced spiral sculpture. (The presence of Koenen’s Early Oligocene North Sea Basin species in the Late Eocene Ukrainian Archipelago requires further research, see Amitrov 2018).
In the Hungarian Paleogene basin system the co-occurring Hemiconus eszterhazyi is a much smaller form.
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Bibliografia
Consultata
