Rhyssoplax olivacea ( Spengler, 1797 ), 2025

Rhyssoplax olivacea ( Spengler, 1797) View in CoL

Fig. 93 View FIGURE 93

Chiton olivaceus Spengler, 1797, p. 73 View in CoL , pl. 6, fig. 8; Seguenza 1874, p. 12; Brugnone 1877, p. 18; Monterosato 1879, p. 13; Seguenza 1879, p. 274, 321, 357; B.D.D. 1882, p. 492; Scalia 1900, p. 16; Sacco 1905, p. 914; Scalia 1906, p. 7; Scalia 1907, p. 29; De Lamothe 1911, p. 277; Dollfus 1920, p. 44; Leloup & Volz 1938, p. 54; Francaviglia 1940, p. 65; Imbesi 1951, p. 127; Blanc et al. 1953, p. 15; Blanc 1953b, p. 26; Segre 1954, p. 56; Comaschi Caria 1955, p. 131; Castany et al. 1956, p. 49; Mars 1956, p. 34; Comaschi Caria 1958, p. 149; Francaviglia 1960, p. 637; Malatesta 1962, p. 161, figs 18–19; Ruggieri 1962, p. 36; Ruggieri & Greco 1965, p. 50; Ruggieri 1967, p. 314; Ruggieri et al. 1968, p. 217; Sabelli & Spada 1970, p. 6; D’Alessandro 1971, p. 383; Colantoni & Borsetti 1973, p. 292; Ruggieri & Milone 1973, p. 221; Laghi 1977, p. 109, pl. 2, figs 5–8; Sabelli & Taviani 1979, p. 161, pl. 1, figs 11–12; Di Geronimo 1979a, p. 47; Caldara & Laviano 1980, p. 63; Porta & Martinell 1981, p. 15; Ferrero Mortara et al. 1984, p. 299; Laghi 1984, p. 559, text-figs 1a–d; Crovato & Taviani 1985, p. 292; Zanaroli 1985, tab. 2; Caldara 1986, p. 136; Macioszczyk 1988, p. 54, pl. 3, figs 4–6; Studencka & Studencki 1988, p. 43, 45; Kaas & Knudsen 1992, p. 59, figs 8b–c; Bellomo & Sabelli 1995, p. 201; Giani 1998, p. 116, pl. 43, fig. 3; Forli et al. 1999, p. 113; Dell’Angelo et al. 2001a, p. 152, fig. 28; Dell’Angelo et al. 2004, p. 39; Dulai & Studencka 2007, p. 17; Vardala-Theodorou & Nicolaidou 2007, p. 64; Foresi et al. 2008, p. 142; Puchalski et al. 2008 (database: chiton fossil records); Studencka & Dulai 2010, p. 266, text-fig. 5; Dell’Angelo et al. 2013, p. 85, pl. 5, figs S–V; Ciampalini et al. 2014, p. 13; Ruman & Hudácková 2015, p. 162, fig. 4.2; Dell’Angelo et al. 2016, p. 76, pl. 1, figs 10–18; Forli & Guerrini 2022, fig. 11.18(11–12).

Chiton olivaceous (sic); Kroh 2002, p. 10.

Clathopleura (sic) olivacea ?; Coppi 1881, p. 87.

Chiton squamosus View in CoL (non Chiton squamosus Linnaeus, 1764 View in CoL ); Philippi 1836, p. 108; Bronn 1848, p. 292; Reid 1890, tab. 3.

Chiton siculus Gray, 1828 View in CoL ; Philippi 1844, p. 83; Bronn 1848, p. 292; Baily 1859, p. 334; Baily 1860, p. 171; Reuss 1860, p. 257, pl. 8, figs 1–3; Seguenza 1862b, p. 30; Conti 1864, p. 26; Unger & Kotschy 1865, p. 43; Appelius 1871, p. 201, 225, 252, 256, 264, 270; Coppi 1876, p. 203; Reid 1892, p. 355; Procházka 1895, p. 100; Procházka 1900, p. 72, 118; Malatesta 1943, p. 165, 167, 178, 181.

Gymnoplax siculus ; de Rochebrune 1882, p. 72.

Chiton polii Deshayes, 1833 View in CoL ; Sismonda 1847, p. 25; Sacco 1889, p. 69.

? Chiton ( Lepidopleurus) sulcatus Risso, 1826 View in CoL ; Tiberi 1877, p. 145, 147.

Clathopleura (sic) sulcatula an. sicula; Coppi 1881, p. 87.

Chiton olivaceus var. plioparva Sacco, 1897, p. 89 , pl. 7, figs 1–5; Malatesta 1962, p. 162; Anfossi et al. 1982, p. 90, pl. 4, fig. 13.

Chiton ( Rhyssoplax) olivaceus View in CoL ; Cavallo & Repetto 1992, p. 30, fig. 3a; Dell’Angelo & Forli 1995a, p. 230, fig. 15; Mancini 1998, p. 29, pl. 1, unnumbered figs; Dell’Angelo & Smriglio 1999, p. 169, pls 56–57, figs 86–96; Dell’Angelo et al. 1999, p. 270, pl. 4, figs 2, 4; Mancini 1999, p. 20; Della Bella & Scarponi 2000, p. 68; Dulai 2005, p. 38, pl. 3, figs 6–8; Garilli et al. 2005, p. 138, pl. 4, figs 1–5; Dell’Angelo & Vardala-Theodorou 2006, p. 328, 3 unnumbered figs; Kaas et al. 2006, p. 151, fig. 55, map 28; Dell’Angelo et al. 2007a, p. 42, figs 4d, 4f.

Rhyssoplax olivacea View in CoL ; Koskeridou et al. 2009, p. 315, figs 9.3–9.4; Dell’Angelo et al. 2021b, p. 420, figs 102–105; Dulai 2025a, p. 9, fig. 15; Dulai 2025b, p. 29, figs 17–19.

Rhyssoplax olivaceus View in CoL ; Sosso & Dell’Angelo 2010, p. 15, unnumbered fig. p. 16; Dell’Angelo et al. 2020b, p. 52, tab. 9.

Chiton zibinicus Doderlein, 1864, p. 15 ; Coppi 1876, p. 203; Tiberi 1877, p. 145; Monterosato 1879, p. 15; Malatesta 1962, p. 162; Van Belle 1981, p. 81; Dell’Angelo & Smriglio 1999, p. 173; Dell’Angelo et al. 2007a, p. 43; Dell’Angelo et al. 2013, p. 85; Dell’Angelo et al. 2016, p. 76.

Chiton olivaceus var. zibinicus ; Sacco 1897, p. 89, pl. 7, figs 6–7.

Rhyssoplax zibinicus ; Puchalski et al. 2008 (database: chiton fossil records).

Gymnoplax bohemicus de Rochebrune, 1882 p. 63 ; Bałuk 1965, p. 368, pl. 1, figs 5–6; Van Belle 1981, p. 25.

Chiton bohemicus ; Šulc 1934, p. 25, pl. 2, figs 48, 50–54; Ashby & Cotton 1935, p. 393; Toth 1942, p. 504; Sieber 1953, p. 184; Fischer P.-H. 1957, p. 21; Sieber 1958, p. 144; Sieber 1959, p. 275; Malatesta 1962, p. 162; Marinescu 1964, p. 180, pl. 2, figs 1–3, pl. 3, fig. 1; Stancu & Andreescu 1968, p. 459; Bałuk 1970, p. 115; Dell’Angelo & Smriglio 1999, p. 173; Garilli et al. 2005, p. 138; Dell’Angelo et al. 2016, p. 76, 98; Dell’Angelo et al. 2018b, p. 52, tab. 17.

Chiton rudelsdorfensis Van Belle, 1980, p. 69 (nom. nov. pro Gymnoplax bohemicus de Rochebrune, 1882 , non Chiton bohemicus Barrande, 1867 ); Van Belle 1981, p. 61.

Chiton jüttneri Šulc, 1934, p. 26 , pl. 2, figs 46–47, 49; Van Belle 1981, p. 44.

Chiton sp. ; Skoczylasówna 1930, p. 68, pl. 1, fig. 8 ( fide Ruman & Hudácková 2015).

Type material. Presumably lost, the type series of Chiton olivaceus is no longer present in the collection of the Zoological Museum of the University of Copenhagen ( fide Kaas & Knudsen 1992: 60) .

Type locality. Off the coast of North Africa .

Material examined. Middle Miocene: Italy (Langhian): Albugnano: 2 valves ( PG); Central Paratethys (Langhian-Serravallian): Austria: Gainfarn: 2 valves ( BD 757), Niederkreuzstetten: 1 valve ( NHMW 1859/0045/0077), Pötzleinsdorf:40 valves ( NHMW 1859/0027/0063, 1861/0028/0078, 2010/0256/0006); Romania: Bujtur: 3 valves ( NHMW 1863/0015/0116), Kostej: 12 valves ( BD 758, NHMW 1869/0001/0796, 1870/0049/0126, 2010/0256/0011), Lăpugiu de Sus: 55 valves ( BD 759, NHMW 1854/0035/0407, 1865/0001/0273, 1868/0001/0633, 1876A/0011/0175); Czech Republic: Porzteich: 23 valves ( NHMW 1871/0010/0210), Rousinov: 1 valve ( NHMW 1861/0011/0409); Hungary: Bánd: 54 valves ( BD 760, Fig. 93E–G View FIGURE 93 ), Letkés: 17 valves ( BD 761), Màrkhàza: 1 valve ( BD 762); Eastern Paratethys: Ukraine: Horodok: 17 valves ( BD 763), Varovtsi: 65 valves ( BD 764, Fig. 93B–D View FIGURE 93 ), Velyka Levada: 1 valve ( BD 765). Upper Miocene: Italy: Borelli: 4 valves ( MGPT PU 135049, PG); Montegibbio: 27 valves ( BD 766, MZB 32070); Rio di Bocca d’Asino: 196 valves ( BD 767, Fig. 93 M–O View FIGURE 93 , PG, MZB 32065- 32069, Figs 93A, 93H, 93P View FIGURE 93 ); S. Agata Fossili: 3 valves ( BD 768); Vigoleno: 7 valves ( BD 769); Villa Monti: 16 valves ( BD 770). Lower Pliocene: Italy: Liguria: Borzoli: 10 valves ( BD 771); Bussana: 8 valves ( BD 772, MZB 45728-45729, Fig. 93I–J View FIGURE 93 ); Caranchi: 3 valves ( MP); Genova Sestri: 3 valves ( BD 773); Rio Torsero: 2 valves ( BD 774). Pliocene: Italy: Piedmont: Baldichieri: 1 valve ( BD 775), San Damiano: 12 valves ( BD 776), Villalvernia: 4 valves ( BD 777), Vintebbio: 3 valves ( BD 778); Tuscany: Castiglioncello del Trinoro: 3 valves ( BD 779), Grotte di Pagnana: 4 valves ( BD 780); Emilia-Romagna: Gagliardella “Tagliata”: 1 valve ( BD 781), Marano sul Panaro: 1 valve ( BD 782), Torrente Stirone: 2 valves ( BD 783); Latium: Montelibretti: 1 valve ( BD 784): Sicily: Trappeto: 4 valves ( BD 785). Pleistocene: Greece: Kyllini: 48 valves ( BD 786, DGUP, Fig. 93K–L View FIGURE 93 ), Loutraki: 33 valves ( BD 787); France: Corsica, Patrimonio: 1 valve ( BD 788); Italy: Emilia-Romagna: Torrente Guerro: 1 valve ( BD 789), Torrente Stirone: 20 valves ( BD 790); Tuscany: Cisternino: 13 valves ( BD 791), Fauglia: 1 valve ( BD 792), Riparbella: 12 valves ( BD 793); Campania: Marina di Camerota : 5 valves ( BD 794); Puglia: Gallipoli: 3 valves ( BD 795), Mar Piccolo: 13 valves ( BD 796), Punta Penne: 7 valves ( BD 797); Calabria: Archi S. Francesco: 78 valves ( BD 798), Bovetto: 1 valve ( BD 799), Carrabbati: 3 valves ( BD 800), Gallina: 2 valves ( BD 801), Le Castella: 432 valves ( BD 802), Musalà: 11 valves ( BD 803), Pecoraro: 5 valves ( BD 804), Petti di Carrubbare: 3 valves ( BD 805), Pezzo: 58 valves ( BD 806), S. Maria di Catanzaro: 4 valves ( BD 807), San Procopio: 5 valves ( BD 808), Saracinello: 1 valve ( BD 809), Stalettì: 15 valves ( BD 810), Torrente Boscaino: 1 valve ( BD 811), Vallone Catrica: 1 valve ( BD 812), Vito Superiore: 2 valves ( BD 813); Sicily: Capo Milazzo: 1 valve ( BD 814), Ficarazzi: 1 valve ( BD 815), Grammichele: 8 valves ( BD 816). Maximum width of the valves: 5 / 12 / 10.7 mm.

Description. Head valve semicircular, front slope faintly convex, posterior margin widely V-shaped, with minute notch in the middle. Intermediate valves broadly rectangular (W/L = 2.09–3.19), rather elevated (dorsal elevation 0.33–0.55), carinated in anterior profile, anterior margin slightly forwardly produced in small central part, side parts somewhat wavy, side margins truncated to weakly convex, posterior margin slightly concave at both sides of minute apex. Tail valve semicircular (W/L = 1.70–2.26), anterior margin convex, mucro subcentral, prominent, antemucronal slope slightly convex, postmucronal slope almost straight to slightly concave.

HV, LA and PMA sculptured with rather coarse, flattish radiating ribs (HV 30–40, LA 2–6, PMA 25–35), often bifurcating, interstices narrower, crossed by several concentric growth lines. CA and AMA sculptured with 14–32 longitudinal folds, jugal area smooth, somewhat with traces of longitudinal folds near apex, innermost folds narrow, close set, not reaching front margin, others gradually becoming broader, more widely spaced and covering entire length of the valve. Aesthetes very dense, each megalaesthete accompanied by many micraesthetes.

Articulamentum with apophyses wide, rounded, tending to trapezoidal in tail valve, jugal sinus narrow, about half of the valve’s width, deep, provided with a concave, dentate plate, teeth short, minutely denticulate, slit formula 8–10 / 1 / 9–14, slits narrow, slit rays very finely indicated, eaves narrow, porous.

Remarks. Rhyssoplax olivacea ( Spengler, 1797) is the most common and best-known Mediterranean species; its remarkable variability led to the description of several species, currently considered synonyms of R. olivacea ( Dell’Angelo & Smriglio 1999; Kaas et al. 2006). Regarding fossil valves, their morphological variability is even stronger, resulting in the description of several taxa, e.g., Chiton zibinicus Doderlein, 1864 from the Tortonian of Montegibbio, and two species from the Paratethys, Gymnoplax bohemicus de Rochebrune, 1882 and Chiton jüttneri Šulc, 1934 .

Chiton zibinicus Doderlein, 1864 was described with the diagnosis: “ Ch. miocenici Micht. prox. sed distinctus ”, without illustrations. Sacco (1897) considered this species as a variety of C. olivaceus , and figured a tail valve (pl. 7, figs 6–7). We follow Sacco (1897), Laghi (1977) and Dell’Angelo et al. (2016) in considering Chiton zibinicus as a synonym of Rhyssoplax olivacea .

Gymnoplax bohemicus de Rochebrune, 1882 was considered by Laghi a synonym of Chiton olivaceus View in CoL , and this synonymy was accepted by subsequent authors (e.g., Dell’Angelo et al. 1999, 2013; Dulai 2005; Studencka & Dulai 2010; Ruman & Hudácková 2015). The taxon Gymnoplax bohemicus cannot be used, since preoccupied by Chiton bohemicus Barrande, 1867 (a species from the Silurian of Bohemia), as reported by Van Belle (1980), which renamed the species Chiton rudelsdorfensis Van Belle, 1980 .

Chiton jüttneri Šulc, 1934 was described on the basis of 3 valves from Rudoltice( Czech Republic), “ characterized by the fact that their median areas bear sharper and more closely spaced grooves, which are not a purely longitudinal oriented, but show a characteristic turn towards the middle ” ( Šulc 1934, p. 26, trans. A. Kroh). This feature is quite frequent in the material under scrutiny, and such as to fall within the intraspecific variability of Rhyssoplax olivacea View in CoL , so we consider Chiton jüttneri as a junior synonym.

The material examined show great variability in the sculpture of the tegmentum, the longitudinal folds on PA may be parallel to each other ( Figs 93B, 93I, 93K View FIGURE 93 ) or obliquely arranged towards the jugal region ( Fig. 93H View FIGURE 93 ), which can be smooth for a large part ( Figs 93E, 93K View FIGURE 93 ) or almost completely covered by folds ( Fig. 93M View FIGURE 93 ). The longitudinal folds on PA normally all reaching the anterior margin, but in some cases the folds near the jugum stop just short of it ( Figs 93H–I View FIGURE 93 ). Furthermore, the number of longitudinal folds and radial ribs is variable; we have recorded 14–32 longitudinal folds and 2–6 radial ribs in the intermediate valves examined.

It should be noted that the sculpture of CA and AMA is not formed by real longitudinal ribs, as in many Rhyssoplax spp . (e.g., R. miocenica ), but rather by the spaces between small folds on the tegmentum, as already reported by Laghi (1977: p. 110 “ aree pleurali incise da solchi longitudinali che in realtà sono gli spazi tra piccole pieghe del tegmentum rovesciate verso il perinoto ”), and as can be seen in the figured valve ( Figs 93J, 93L View FIGURE 93 ).

Some valves show a well-defined dental plate in the jugal sinus, as the figured valve ( Figs 93E–G View FIGURE 93 ) from the Paratethys.

The sculpture of the dorsal surface has been well highlighted by Fischer & Renner (1979).

Comparisons. The more similar species is Rhyssoplax miocenica ( Michelotti, 1847) , and the differences with this species are discussed above.

Distribution. Middle Miocene: Mediterranean Sea (Langhian): France: La Chausserie ( Dollfus 1920); Italy: Po Basin: Albugnano ( Dell’Angelo et al. 2016); Central Paratethys (Langhian-Serravallian): Austria: Gainfarn, Niederkreuzstetten, Pötzleinsdorf ( Šulc, 1934); Czech Republic: Borač, Knínice, Porzteich, Rousinov, Rudoltice ( Šulc 1934); Slovakia: Rohožník ( Ruman & Hudácková 2015); Poland: Lychów, Niskowa, Węglin, Weglinek ( Skoczylasówna 1930; Bałuk, 1965; Macioszczyk, 1988); Hungary: Bánd, Devecser, Letkés, Màrkhàza ( Dulai 2005, 2025 a, 2025b; this study), Romania: Băseşti, Bujtur, Coştei, Lăpugiu de Sus ( Šulc 1934; Zilch 1934; Marinescu, 1964; Dell’Angelo et al. 2007a); Eastern Paratethys: Ukraine: Horodok, Varovtsi, Velyka Levada ( Studencka & Dulai, 2010; this study). Upper Miocene: Proto-Mediterranean Sea (Tortonian): Po Basin, N Italy: Borelli, Montegibbio, Rio di Bocca d’Asino, S. Agata Fossili, Vigoleno, Villa Monti ( Laghi 1977; Dell’Angelo et al. 1999, 2016). Lower Pliocene: northeastern Atlantic: U.K. ( Reid 1890, 1892); central Mediterranean, Italy: Liguria: many localities ( Sosso & Dell’Angelo 2010; Dell’Angelo et al. 2013). Pliocene: central Mediterranean, Italy: many localities in Piedmont, Emilia-Romagna, Tuscany, Latium, Sicily ( Dell’Angelo et al. 2001a, 2013; Sosso & Dell’Angelo 2010; this study); France: Biot (B.D.D. 1882). Upper Pliocene to upper Pleistocene: Greece: Rhodes Island ( Koskeridou et al. 2009). Lower Pleistocene: central Mediterranean, Italy: Torrente Stirone ( Sabelli & Taviani 1979). Pleistocene: central Mediterranean: Greece and Cyprus ( Garilli et al. 2005); France: Corsica, Patrimonio (this paper); Italy: many localities in Emilia-Romagna, Tuscany, Campania, Puglia, Calabria, Sicily ( Dell’Angelo et al. 2001a; this paper), Tunisia: Monastir ( Castany et al. 1956), Algeria: Arzeu ( De Lamothe 1911). Recent: Atlantic Ocean, Spain (Carmona Zalvide et al. 2000), Portugal ( Consolado Macedo et al. 1999), Morocco ( Pallary 1920) and Berlengas Arch. ( Pisani Burnay 1986); Mediterranean Sea. Spain ( Salas & Luque 1986; Giribet & Penas 1997), France (B.D.D 1982), Italy: many localities ( Monterosato 1879; Dell’Angelo & Smriglio 1999; Kaas et al. 2006; Trono 2006); Croatia: Dell’Angelo & Zavodnik 2004; Greece and Aegean Sea Islands ( Strack 1988, 1990; Koukouras & Karachle 2005); Malta ( Mifsud et al. 1990); Turkey ( Öztürk et al. 2014); Tunisia ( Kaas 1989; Cecalupo et al. 2008); Israel ( Barash & Danin 1977); Lebanon ( Crocetta et al. 2014); Marmara Sea ( Öztürk et al. 2014).