Lepidopleurus cajetanus ( Poli, 1791 )

Lepidopleurus cajetanus ( Poli, 1791) View in CoL

Fig. 3 View FIGURE 3

Chiton cajetanus Poli, 1791, p. 10 , pl. 4, figs 1–2; Costa 1854 -1856, p. 348; Unger & Kotschy 1865, p. 43; Appelius 1871, p. 270; Seguenza 1874, p. 12; Brugnone 1877, p. 18; Tiberi 1877, p. 142, 147, 157; Seguenza 1879, p. 274; Coppi 1880, p. 227; Scalia 1900, p. 15; Scalia 1907, p. 29; Malatesta 1943, p. 181.

Chiton foliatus Allan, 1818, p. 459 , pl. 9, fig. 1 ( fide Dell’Angelo & Palazzi 1989).

Chiton decoratus Reuss, 1860, p. 257 , pl. 8, fig. 7; Procházka 1900, p. 72, 118; Laghi 1977, p. 98.

Lepidopleurus decoratus View in CoL ; de Rochebrune 1882, p. 62; Šulc 1934, p. 3; Ashby & Cotton 1935, p. 389; Toth 1942, p. 504; Sieber 1953, p. 184; Sieber 1958, p. 143; Sieber 1959, p. 275; Malatesta 1962, p. 146; Bałuk 1965, p. 366, pl. 1, figs 1–4; Bałuk 1970, p. 115; Bałuk 1971, p. 453, pl. 1, figs 1–4; Sabelli & Spada 1971, p. 6; Bałuk & Radwanski 1979, p. 230; Van Belle 1981 a, p. 33; Zanaroli 1985, p. 66; Wysocka et al. 2016, p. 377.

Chiton Reussi Procházka (non Chiton reussi Rolle, 1862 ); Procházka 1900, p. 72, 118, fig. 29.

Holochiton cajetanus ; B.D.D. 1882, p. 502; Almera 1894, p. 197; Almera & Bofill 1898, p. 173; Blanc 1953, p. 12; Castany et al. 1956, p. 49.

Holochiton ( Lepidopleurus) cajetanus ; Ruggieri 1942, p. 84.

Lepidopleura caietana (sic); Coppi 1881, p. 87.

Lepidopleurus caietanus (sic); Ruggieri 1953, p. 40.

Lepidopleurus cajetanus View in CoL ; de Rochebrune1882, p. 72; Sacco 1897, p. 90, pl. 7, figs 26–31; Leloup & Volz 1938, p. 47; Francaviglia 1960, p. 637; Sabelli & Spada 1971b, p. 6; Ruggieri & Milone 1973, p. 221; Laghi 1977, p. 95, pl. 1, figs 13–20; Di Geronimo 1979a, p. 47; Sabelli & Taviani 1979, p. 161, pl. 1, figs 1–3; Laghi & Russo 1980, p. 322, pls 1–3; Bałuk 1984, p. 284, pl. 4, figs 1–2; Ferrero Mortara et al. 1984, p. 299; Francou 1984, p. 60; Laghi 1984, p. 556; Sabelli & Taviani 1984, p. 269; Bertarelli & Inzani 1985, p. 299; Kaas & Van Belle 1985a, p. 32, fig. 12; Zanaroli 1985, p. 65; Caldara 1986, p. 136; Macioszczyk 1988, p. 50, pl. 1, figs 1–5; Studencka & Studencki 1988, p. 39, pl. 1, figs 1–3; Tabanelli & Segurini 1994, p. 7; Bellomo & Sabelli 1995, p. 201; Giani 1998, p. 114, pl. 43, fig. 5; Buccheri et al. 1999, p. 366; Forli et al. 1999, p. 111, pl. 1, figs 1–3, 9; Kroh 2002, p. 10; Forli et al. 2003, p. 152; Kroh 2003, p. 131, pl. 1, fig. 1, pl. 2, figs 2–3; Chirli 2004,

p. 4, pl. 1, figs 9–15; Dulai & Studencka 2007, p. 17; Puchalski et al. 2008 (database: chiton fossil records); Koskeridou et al. 2009, p. 305, figs 7.1–7.3; Sosso & Dell’Angelo 2010, p. 14, unnumbered fig. p. 16; Studencka & Dulai 2010, p. 261, text-fig. 3A–G; Dell’Angelo et al. 2013, p. 68, pl. 1, figs A–M; Moissette et al. 2013, p. 17; Ciampalini et al. 2014, p. 13; Dell’Angelo et al. 2015a, p. 220, pl. 1; Ruman & Hudácková 2015, p. 158, fig. 5.4; Dell’Angelo et al. 2016, p. 96; Dell’Angelo et al. 2018a, p. 11, figs 2A–I; Dell’Angelo et al. 2018b, p. 6, figs 2A–L; Dell’Angelo et al. 2020b, p. 52, tab. 9; Dell’Angelo et al. 2021b, p. 407, figs 2–13; Forli & Guerrini 2022, fig. 11.18 (7–10); Dulai 2025b, p. 25, figs 5–7.

Lepidopleurus ( Lepidopleurus) cajetanus View in CoL ; Malatesta 1962, p. 146, figs 1–2; Marinescu 1964, p. 180, pl. 1; Ruggieri et al. 1968, p. 217; Buccheri 1970, p. 245, 255; D’Alessandro 1971, p. 383; Ricchetti & D’Alessandro 1972, p. 133; Dell’Angelo & Palazzi 1989, p. 45, pls 1–2; Dell’Angelo & Forli 1995a, p. 223, fig. 18; Dell’Angelo & Smriglio 1999, p. 38, pls 6–7, figs 10–15; Dell’Angelo et al. 1999, p. 260, pl. 1, figs 2, 4–7; Mancini 1999, p. 20; Dell’Angelo et al. 2001a, p. 145, figs 1, 4; Dell’Angelo et al. 2004, p. 26, pl. 7, figs 4, 8; Dulai 2005, p. 30, pl. 1, figs 1–10, pl. 2, figs 1–6; Garilli et al. 2005, p. 129, pl. 1, figs 1–2; Dell’Angelo et al. 2007a, p. 40, fig. 4a.

Lepidopleurus ( Leptochiton) cajetanus View in CoL ; Mancini 1998, p. 27, pl. 1, unnumbered figs.

Chiton sp. Vetters, 1910, p. 157 ( fide Kroh 2003).

Type material. Probably lost. Lectotype designated by Dell’Angelo & Palazzi (1989), specimen figured by Poli (1791: pl. 4, fig. 1).

Type locality. Gaeta ( Italy) .

Material examined. Lower Miocene: France, Aquitaine Basin (Burdigalian): Pont St Martin: 1 valve ( PR). Middle Miocene: France, Northeastern Atlantic (Langhian): Pouyouet: 1 valve ( PR); Central Paratethys: Austria: Grund: 1 valve ( NHMW 2010/0256/0020), Niederkreuzstetten: 1 valve ( NHMW 2010/0256/0002), Niederleis: 2 valves ( NHMW 1863/0015/0860), Pötzleinsdorf: 163 valves ( NHMW 1859/0027/0060–0061, Figs 3J–K View FIGURE 3 , 1859/0038/0191, Figs 3F–I View FIGURE 3 , 1861/0028/0079, 1865/0001/0987), Speising: 1 valve ( NHMW 1860/0028/0108); Romania: Bujtur: 2 valves ( NHMW 1863/0012/0116), Kostej: 5 valves ( BD 263, NHMW 1867/0019/0345), Lapugy: 14 valves ( BD 264, NHMW 2010/0256/0004, 2010/0256/0024); Hungary: Bánd: 78 valves ( BD 265), Letkés: 6 valves ( BD 266); Eastern Paratethys: Ukraine: Horodok: 4 valves ( BD 267), Varovtsi: 1 valve ( BD 268), Velyka Levada: 1 valve ( BD 269). Upper Miocene: France, Ligerian Basin (Tortonian): Moulin Pochas: 20 valves ( PR); Anjou: Saint-Clément-de-la-Place: 79 valves ( MNHN.F.A67042–A67046, NHMW 2017/0108/0001, RGM.1008397, BD 129, Figs 3O–P View FIGURE 3 ), Renauleau: 17 valves ( MNHN.F.A67047–A67048, NHMW 2017/0108/0002, BD 130), Sceaux d’Anjou: 3 valves ( RGM.1008442, RGM.1008447); Italy, Po Basin (Tortonian): Borelli: 38 valves ( BD 270, Figs 3A–B View FIGURE 3 , MGPT PU 135037, MZB 32003, MZB 32007, PG), Montegibbio: 21 valves ( BD 271, MZB 32004, MZB 32006), Rio di Bocca d’Asino: 58 valves ( MZB 32001–32002, BD 272, Figs 3M–N View FIGURE 3 , PG), Vigoleno: 1 valve ( MZB 32044), Villa Monti: 79 valves ( BD 273, MZB 32005, PG). Lower Pliocene: Italy: Liguria: Borzoli: 1240 valves ( BD 274, MSNG, Figs 3C–E View FIGURE 3 , MZB 45692, MZB 45695, MZB 45697–45698), Bussana: 269 valves ( BD 275, MZB 45690–45691, PG, SR), Garlenda: 67 valves ( MP), Genova Sestri: 11 valves ( BD 276), Rio S. Antonino: 2280 valves ( BD 277, MP, MZB 45693–45694, MZB 45696, PG), Rio Torsero: 2 valves ( BD 278, MP), Caranchi: 5 valves ( MP), Salea: 1 valve ( BD 279), Zinola: 13 valves ( BD 280). Pliocene: Spain: Estepona: 7 valves ( BD 281); Italy: Piedmont: Vintebbio: 11 valves ( BD 282); Tuscany: Castiglioncello del Trinoro: 2 valves ( BD 283), Montenero: 11 valves ( BD 284), Serre di Rapolano: 60 valves ( BD 285), Villa Banfi: 3 valves ( BD 286); Emilia-Romagna: Bacedasco: 11 valves ( BD 287), Gagliardella: 3 valves ( BD 288), Sariano: 1 valve ( BD 289), Vernasca: 14 valves ( BD 290); Sicily: Trappeto: 11 valves ( BD 291). Pleistocene: France: Corsica, Patrimonio: 8 valves ( BD 292); Italy: Tuscany: Cisternino: 32 valves ( BD 293), Riparbella: 3 valves ( BD 294); Emilia-Romagna: Torrente Stirone: 20 valves ( BD 295); Tuscany: Fauglia: 2 valves ( BD 296); Puglia: Gallipoli: 2 valves ( BD 297), Punta Penne: 3 valves ( BD 298); Calabria: Archi S. Francesco: 8 valves ( BD 299), Gallina: 3 valves ( BD 300), Le Castella: 20 valves ( BD 301), Musalà: 8 valves ( BD 302), Pecoraro: 3 valves ( BD 303), Pezzo: 13 valves ( BD 304), S. Maria di Catanzaro: 3 valves ( BD 305), Stalettì: 3 valves ( BD 306), Terreti: 4 valves ( BD 307); Sicily: Calderà: 1 valve ( BD 308), Capo Milazzo: 8 valves ( BD 309), Grammichele: 3 valves ( BD 310), Messina : 1 valve ( BD 311); Greece: Kyllini: 2 valves ( DGUP, Fig. 3L View FIGURE 3 ). Maximum width of the valves: 8.3 / 10 / 8 mm.

Description. Valves solid. Head valve semicircular, posterior margin almost straight, front slope weakly concave, interrupted by profile of concentric, terraced ribs. Intermediate valves broadly rectangular, with a very variable width/length ratio (H/W = 2.41–3.60), rounded in anterior profile, moderately elevated (H/W = 0.28–0.40), anterior margin variable, from concave to straight or convex, lateral margins almost straight or slightly rounded, posterior margin straight with apex not evident, lateral areas triangular, strongly elevated, starting from near the apex to neighbouring the lateral margin, moderately angled (30–45°) to the posterior margin. Tail valve semicircular, shape strongly variable with size, anterior margin straight or little convex, mucro evident and variable with size from subcentral to forwardly produced, antemucronal slope almost straight, postmucronal slope variable with size.

Tegmentum coarse, very variable. HV, LA and PMA sculptured with strong, concentric, terraced ribs, spaced from each other.CA and AMA sculptured with longitudinal chains of granules, somewhat branching or anastomosing, transversally intersected by much thinner cords that give a pitted appearance, more evident in younger individuals. Granules of irregular shape, from roundish to polygonal, up to 100 µm long, elevated, united with each other, with one subcentral megalaesthete and up to 10 micraesthetes placed on both sides of granules.

Articulamentum without insertion laminae, apophyses small, triangular, divided by a wide jugal sinus.

Remarks. The species displays considerable morphological variations from juvenile stages to adulthood. Laghi (1977: fig. 3a-b) documented that the mucro of tail valves is almost central in juvenile specimens, moving backward (up to the end of the valve) with growth, due to the bending of the posterior area on the ventral side. The first postlarval stage of juvenile Lepidopleurus cajetanus ( Poli, 1791) is characterized by a leptochitonid-like sculpture, i.e. with small cords of tubercles but without the presence of “steps” (terraced ribs) on the valves and with the mucro anterior or pre-central. Later, the typical ‘step’ sculpture appears but the mucro is still subcentral and the small cords of tubercles are not cancelled ( Figs 3L View FIGURE 3 ). In the final stage, the small cords are almost indistinguishable in the “step” zone, while the mucro is situated more posteriorly and the outline is more triangular ( Fig. 3O–P View FIGURE 3 ). These features have well described and illustrated by Laghi (1977: fig. 3a–b), and Dell’Angelo et al. (2013: pl. 1, figs F–G; 2015a: pl. 1, figs 9–12).

The morphology of intermediate valves attributed in the literature to Lepidopleurus cajetanus , consists, in fact, of two distinct types of LA. The first type ( Lepidopleurus cajetanus ), has the starting point of the lateral area with the concentric terraced ribs near the apex, more regular, slightly angulated on the posterior margin (30–45°), rounded in anterior profile but the valve is not very elevated (H/W = 0.28–0.40). The second type shows the starting point of the lateral area with the concentric terraced ribs neighbouring the lateral margin (not near the apex), much more angled at the posterior margin, from 50–60° upwards up to almost perpendicular, rounded in anterior profile but more elevated (H/W = 0.40–0.64), in addition to other minor features (see below). These remarkable differences may well account for representing two distinct taxa, which can, however, be discriminated only upon intermediate valves. A new species, Lepidopleurus pseudocajetanus sp. nov. is described below.

Another remarkable example of variation in the sculpture of the tegmentum can be evidenced in CA and AMA, normally with longitudinal chains of granules ( Fig. 3C View FIGURE 3 ), somewhat branching or anastomosing, transversally intersected by thinner cords that give a pitted appearance ( Fig. 3M View FIGURE 3 ). The longitudinal chains may be irregularly directed towards the sides in some cases ( Fig. 3L View FIGURE 3 ), but the sculpture of “parallel” chains is always well evident. This type of sculpture is prevalent in Recent specimens (see Dell’Angelo & Smriglio, 1999: pl. 6, fig. E, pl. 7, figs K, L), but also in valves from Pleistocene and Pliocene (see Garilli et al. 2005: pl. 1, fig. 1 from the Pleistocene of Kyllini, Greece; Dell’Angelo et al. 2013: pl. 1, fig. B from the Pliocene of Liguria). The sculpture prevailing in Miocene specimens is more irregular and rougher, shaped by groups of granules branching longitudinally many times, and giving an appearance without evidence of longitudinal chains ( Fig. 3J View FIGURE 3 ). Furthermore, the intersections by thinner cords are not present. The variability is very large, with multiple branching occurring only in a part of the central area of some valves. Although less frequently, such irregular sculpture may also occur in Pliocene to modern valves.

The great variability of the valves and the remarkable variations in morphology with age found in Lepidopleurus cajetanus , is confirmed by the check of the valves of L. decoratus ( Reuss, 1860) present in the Šulc collection. The same degree of variability is also present in valves from the Paratethys ( Dulai 2005; Studencka & Dulai 2010), as already reported by Reuss and Šulc (see Reuss, pl. 8, fig. 7). We can therefore confirm that L. decoratus must be considered a synonym of L. cajetanus .

Comparisons. The characteristics of the tegmentum sculpture (with the presence of strong, concentric, terraced ribs on HV, LA, PMA) make this species easily identifiable and unmistakable.

Distribution. Lower Miocene: northeastern Atlantic (Burdigalian): Aquitaine Basin, France: Pont St Martin ( Dell’Angelo et al. 2018a). Middle Miocene: northeastern Atlantic (Langhian): Aquitaine Basin, France: Pouyouet ( Dell’Angelo et al. 2018a); Central Paratethys (Langhian-Serravallian): Austria: Grund, Niederkreuzstetten, Niederleis, Pötzleinsdorf, Speising, Steinabrunn ( Šulc 1934; this study), Czech Republic: Borač, Kninice, Rudoltice ( Šulc 1934), Slovakia:Dubová( Ruman&Hudácková2015), Poland:Korytnica ( Bałuk, 1971, 1984), Romania:Bujtur, Coştei, Lăpugiu de Sus ( Zilch 1934; Dell’Angelo et al. 2007a; this study), Hungary: Bánd, Letkés ( Dulai 2005, 2025b; this study); Eastern Paratethys: Ukraine: Horodok, Podhorce, Szuszkovce, Varovtsy, Velyka Levada ( Studencka & Dulai 2010; this study). Upper Miocene: northeastern Atlantic: Ligerian Basin, France: Moulin Pochas, Saint-Clément-de-la-Place, Renauleau, Sceaux d’Anjou ( Dell’Angelo et al. 2018a, 2018b); Proto-Mediterranean Sea: Po Basin, N Italy: Borelli, Montegibbio, Rio di Bocca d’Asino, Vigoleno, Villa Monti ( Laghi 1977; Dell’Angelo et al. 1999, 2015a). Lower Pliocene: central Mediterranean, Italy: many localities in Liguria ( Laghi 1977; Dell’Angelo et al. 2001a, 2013; Chirli 2004). Pliocene: Western Mediterranean, Spain: Estepona (Dell’Angelo et al. 2004); France: Biot (B.D.D. 1882); Italy: many localities in Piedmont, Tuscany, Emilia-Romagna, Sicily. Upper Pliocene to upper Pleistocene: central Mediterranean, Greece: Rhodes ( Koskeridou et al. 2009). Pleistocene: central Mediterranean, Italy: many localities in Tuscany, Puglia, Calabria, Sicily ( Sabelli & Taviani 1979; Dell’Angelo & Palazzi 1989; Dell’Angelo et al. 2001a); Greece: Kyllini ( Garilli et al. 2005), Tunisia: Monastir ( Castany et al. 1956). Recent: Atlantic Ocean, from Spain and Portugal ( Borja 1987; Consolado Macedo et al. 1999; Urgorri et al. 2017) south to Morocco ( Pallary 1920) and Canary Islands ( Kaas 1991; Hernández & Rolán 2011) and Berlengas Archipelago ( Pisani Burnay 1986). Mediterranean Sea: Spain and Balearic Islands ( Altaba 1993; Moreno & Gofas 2011); France (B.D.D. 1882; Leloup 1934); Italy: Lampedusa Island ( Spada et al. 1973) and many localities ( Leloup & Volz 1938; Dell’Angelo & Smriglio 1999); Croatia ( Leloup & Volz 1938); Malta ( Mifsud et al. 1990); Greece and Aegean Sea Islands ( Strack 1988; Koukouras & Karachle 2005); Turkey ( Demir 2003; Ozturk et al. 2014); Israel ( Barash & Danin 1977); Libia ( Monterosato 1923); Algeria: Orano ( Pallary 1900).