Thericium chamaeleo, Harzhauser & Guzhov & Landau, 2025

Harzhauser, Mathias, Guzhov, Aleksandr & Landau, Bernard, 2025, A revision of the Cainozoic Cerithiidae and Plesiotrochidae (Mollusca: Caenogastropoda) of the Paratethys Sea (Europe, Asia), Zootaxa 5625 (1), pp. 1-180 : 102-103

publication ID	https://doi.org/10.11646/zootaxa.5625.1.1
publication LSID	lsid:zoobank.org:pub:E4AB35FE-B158-4722-A849-C271E419DEE7
persistent identifier	https://treatment.plazi.org/id/211887DE-3554-DC7F-FF54-8356F6AFFCDC
treatment provided by	Plazi
scientific name	Thericium chamaeleo
status	sp. nov.

Treatment

Thericium chamaeleo sp. nov.

Figs 27D, 45A–F View FIGURE 45

Cerithium crenatum Brocc. View in CoL var.— Hörnes 1855: 408 (pars) [non Thericium crenatum ( Brocchi, 1814) View in CoL ].

Type material. Holotype NHMW 1879 View Materials /0033/0147, SL: 39.2 mm, MD: 11.1 mm, Lăpugiu de Sus ( Romania), Figs 45F View FIGURE 45 1 –F View FIGURE 1 2 View FIGURE 2 . Paratypes, NHMW 1854 View Materials /0035/0296, SL: 32.6 mm, MD: 11.5 mm, Lăpugiu de Sus ( Romania), Figs 27D, 45D View FIGURE 45 1 –D View FIGURE 1 2 View FIGURE 2 . NHMW 2023 View Materials /0042/0001, SL: 35.7 mm, MD: 11.4 mm, Lăpugiu de Sus ( Romania), Figs 45C View FIGURE 45 1 –C View FIGURE 1 2 View FIGURE 2 . NHMW 2023 View Materials /0042/0002, SL: 22.0 mm, MD: 7.9 mm, Lăpugiu de Sus ( Romania), Figs 45A View FIGURE 45 1 –A View FIGURE 1 2 View FIGURE 2 . NHMW 2023 View Materials /0043/0001, SL: 27.1 mm, MD: 9.7 mm, Coşteiu de Sus ( Romania), Figs 45B View FIGURE 45 1 –B View FIGURE 1 2 View FIGURE 2 . NHMW 2023 View Materials /0043/0002, SL: 26.4 mm, MD: 8.8 mm, Coşteiu de Sus ( Romania), Figs 45E View FIGURE 45 1 –E View FIGURE 1 2 View FIGURE 2 .

Additional paratypes. 1spec. NHMW2023 View Materials /0044/0001, Nemeşeşti ( Romania) ; 1spec., NHMW1866 View Materials /0040/0325, Lăpugiu de Sus ( Romania) ; 31 spec. NHMW 1854 View Materials /0035/0297, Lăpugiu de Sus ( Romania) ; 1 spec., NHMW 1868 View Materials /0019/0190, Coşteiu de Sus ( Romania) ; 4 spec., NHMW 2023 View Materials /0043/0003, Coşteiu de Sus ( Romania) .

Type locality. Lăpugiu de Sus ( Romania), Făget Basin.

Type stratum. Silt and clay of the Dej Formation.

Age. Middle Miocene, early/middle Badenian (Langhian).

Etymology. After the chamaeleon genus Chamaeleo , referring to the changeable sculpture and the fact the shells were hidden amongst other species in the collections.

Diagnosis. Medium sized, slender shell with subcylindrical whorls, characterized by change in sculpture from predominant spiral sculpture on early teleoconch whorls, then prominent axial ribs mid-spire and last whorls again with prominent spiral cords with tubercles. Aperture relatively narrow with crenulated outer lip.

Description. Medium sized, slender shell with cyrtoconoid spire of up to 11 teleoconch whorls, attaining 22–39 mm in height; apical angle 35–45°. Protoconch unknown. Early teleoconch whorls convex with periphery slightly above abapical suture. Sculpture of three narrow primary spiral cords. One secondary spiral thread intercalated between each pair of primaries and on narrow subsutural ramp. Intermediate whorl profile subcylindrical; sculpture changing around fifth teleoconch whorl by appearance of axial ribs and tuberculose subsutural spiral cord. Axial ribs on sixth to seventh teleoconch whorl prominent, terminating in weakly pointed tubercles at subsutural ramp. Suture moderately incised, weakly undulating. On late whorls axial ribs disintegrating into three primary spiral rows of close-set, prominent, pointed to rounded tubercles placed at adapical and abapical suture and just above mid-whorl. Prominent secondary spiral cord between adapical primary cords and two secondaries between lower pair of primaries, the upper of these two secondaries weakly tubercular in some specimens, adjoined by weaker tertiary threads. Last whorl high, weakly convex, attaining ~40–45% of total height. Base weakly constricted. Second spiral cord (= mid-whorl cord) most prominent with slightly pointed tubercles, coinciding with faint angulation. Single varix present on spire whorls in some specimens, plus single varix on last whorl placed about 90°behind outer lip edge. Base with prominent, weakly tubercular peribasal spiral cord, two further strong cords over base, plus secondary cords in some specimens. Aperture ovate, relatively narrow. Columella broadly and shallowly excavated. Columellar callus forming thick, broad rim, sharply delimited from base. Anal canal narrow, deeply incised, low parietal denticle. Outer lip not thickened, crenulated. Siphonal canal moderately long and wide, recurved, slightly deflected to the left.

Discussion. This species is characterized by its twofold change in sculpture during ontogeny and by the elongate bullet-shaped outline of fully-grown specimens. Despite these typical features, the shells were mixed in the NHMW collection with other species of the Thericium crenatum group, such as Thericium poetzleinsdorfense ( Sacco, 1895) . These differ clearly in their early teleoconch whorls, which bear axial ribs. There are no other similar species in the Paratethys. Thericium crenatum ( Brocchi, 1814) , from the Mediterranean Pliocene, differs in its more delicate sculpture with much weaker tubercles and the varix on the last whorl is opposite the outer lip.

Paleoenvironment. Unknown.

Distribution. Only known from the Badenian (Langhian) of the Făget Basin in Romania, suggesting a distribution in the southern part of the Central Paratethys Sea.

Central Paratethys. Badenian (Middle Miocene): Făget Basin: Coşteiu de Sus, Lăpugiu de Sus, Nemeşeşti ( Romania) (hoc opus).