Family Thelypteridaceae Holttum 1971
(Unger) Knobloch et Kvaček 1976
Figs. 5, 6, 7, 8
1847 Polypodites stiriacus Unger, pp. 121–122, pl. 36, figs. 1, 2, 3, 4, 5;
1976 Pronephrium stiriacum Knobloch et Kvaček, p. 12, pl. 1, fig. 1;
1985 Pronephrium stiriacus Hably, pp. 11, 23, 24, 26, 27;
1986 Pronephrium stiriacus Givulescu, p. 179;
1986 Pronephrium stiriacum Petrescu et Givulescu, p. 110;
1991 Pronephrium stiriacum Kvaček et Hably, p. 52, pl. 1, fig. 2;
1995 Pronephrium stiriacum Kvaček et Walter, p. 39, text-fig. 4, pl. 1, fig. 1;
1996 Pronephrium stiriacus Givulescu, pp. 15–17, pl. 30, fig. 1;
1997 Pronephrium stiriacum Petrescu et al., p. 39, pls. 1, 20, figs. 3, 6;
1998 Pronephrium stiriacum Kvaček et Walter, p. 25, pl. 13, fig. 9;
1999 Pronephrium stiriacum Givulescu, p. 27, pl. 1, fig. 5;
2000 Pronephrium stiriacum Kvaček et Hurnik, p. 4, text-fig. 1.1, pl. 1, figs. 1, 2;
2004 Pronephrium stiriacum Kovar-Eder et al., p. 52, pl. 1, fig. 3;
2004 Pronephrium stiriacum Erdei et Wilde, p. 120, text-fig. 7;
2007 Pronephrium stiriacum Kvaček et Teodoridis, pp. 391, 395, 400, 402, 403;
2007 Pronephrium stiriacum Teodoridis, p. 416;
2007 Pronephrium stiriacum Walter et Kvaček, p. 91, pl. 1, figs. 1, 2, 3, 4, 5, 6, 7, 8;
2011 Pronephrium stiriacum Kvaček et al., p. 10, pls. 1, 9, figs. 1, 15;
2013 Pronephrium stiriacum Hably, pp. 39–40, pls. 1, 35, figs. 2, 3, 4, 5;
2013 Pronephrium stiriacum Hably et Magyar, p. 17;
2014 Pronephrium stiriacum Velitzelos et al., pp. 58, 59, pl. I, figs. 1, 2, 3;
2015 Pronephrium stiriacum Hably et al., p. 287, fig. 3.
The Petroșani Oligocene material
The hand specimen from Aninoasa yields three exceptional fragments, a large fragment exposing the abaxial surface of the leaf (F1), an apical fragment exposing the adaxial surface (F2) and a small, detached pinnule (F3; Fig. 5, with fragments marked with F1–F3). The leaf is unipinnate and imparipinnate, with pinnules having a thin lamina substance. The apical part of the frond has an elongated apical pinnule prolonging the rachis (Figs. 5, 6). The primary rachis is 3–4 mm wide, 4 mm wide at the base of the fragment, 3 mm wide to the apical end of the fragment, while the length of the fragmented rachis is 170 mm. The rachis is straight, smooth, with a longitudinal, short and slightly rounded median ridge (Figs. 5, 6). In cross section, the rachis is triangular or V-shaped. No clear hair bases or scales occur along the primary rachis. The pinnules are strongly elongated in shape, lanceolate, short petiolate, with an asymmetrical base, dentate margins and acute apex (Figs. 5, 6, 9a). The petiole is less than 1 mm long and 1 mm wide. The pinnules are inserted suboppositely to alternately to the rachis, with angles between 45°–50° (Fig. 5). The basiscopic part of the pinnule’s base is rounded, and the acroscopic part of the base is straight, parallel to the rachis (Figs. 5, 6). The pinnules are 100–170 mm long and 10–15 mm wide at the base, where they are the widest. The usual width of the pinnules varies between 14–15 mm. The pinnule margins are dentate, with falcate and wide teeth, sometimes even slightly mucronate, separated by narrow and shallow sinuses. The teeth are usually 0.5–0.7 mm long, while the smallest pinnules are weakly dentate (Figs. 5, 6, 9a). The venation is prominent abaxially and weakly expressed adaxially. The midrib is 0.9–1 mm wide, rounded or slightly ridged abaxially, slightly depressed adaxially, straight, reaching the pinnule’s apex. No hair bases occur along the midrib (Figs. 6a, c, 9a). The secondary veins are straight, inserted oppositely to suboppositely to the midrib. Each secondary vein reaches the apex of a marginal tooth. The secondary veins are very narrow, about 0.2 mm wide. The tertiary veins are straight, inserted oppositely to the secondary veins, interconnected to the neighboring tertiary veins along a straight, interconnecting vein reaching each sinus between two neighboring marginal teeth (Fig. 6b, c). The sori occur in the middle of each tertiary vein and the interconnecting vein (Figs. 6b, 7a, 9a). Each sorus is circular, about 0.6–0.8 mm in diameter. Unfortunately, all sori are missing along the tertiary veins, leaving a circular piercing in the thin lamina. The only exception is a poorly preserved fertile fragment occurring on the hand specimen UPLU0010 from the Lupeni sterile dump, with sori reaching 0.6–0.8 mm in diameter (Fig. 7). These sori are irregular clusters of sporangia, very difficult to separate due to the poor preservation (Fig. 7). They usually occur to the middle part of the tertiary veins, uniformly distributed between the midrib and pinnule margins.
The Bozovici Miocene material
The collected material includes only dispersed pinnules, both sterile and fertile. The pinnules are short petiolate, elongated in shape, linear, with a slightly asymmetric base, with strongly dentated margins and acute apices (Fig. 8a, b). The marginal teeth are symmetrical, with a slightly attenuated apex, and they are separated by a symmetrical, wide sinus. The pinnules’ length varies between 40–60 mm, and their width varies between 10–15 mm, with the widest part toward the pinnule base. The petiole is 4–5 mm long and 0.5 mm wide, ornamented with fine longitudinal striae (Fig. 8b). The midrib is 0.5–0.7 mm wide, finely striated longitudinally, with a short ridge along the abaxial surface. The rachis is marked along its abaxial surface by rare dots representing large trichomial bases (Fig. 8b, c). The secondary veins are more prominent abaxially, they are inserted oppositely to the midrib at angles between 70°–80°, and they are straight, smooth, reaching each apex of the marginal tooth (Figs. 8c, d, 9b). The tertiary veins are also straight, inserted oppositely to the secondary veins, and about five tertiary veins along each secondary one. Their tertiaries interconnect with their neighboring counterparts, thus a supplementary vein is generated, reaching each marginal sinus (Figs. 8c, d, 9b). In fertile pinnules, the sori occur along the tertiary veins in the middle region between the secondary veins and the supplementary veins (Figs. 8c, d, 9b). They are usually circular, 0.7–1.0 mm in diameter and few reniform (Fig. 8d, middle one), with numerous small, spherical sporangia distributed irregularly but clustered. Nearly 12–17 sporangia occur in each sorus, but their precise number is difficult to assess. No indusium and no in-situ spores were observed (Fig. 8c, d). Their distribution is uniform, occurring in the middle, between connecting veins and secondary veins, always on the tertiary veins.
We consider pinnules as the large, petiolate, laminate and dentate structures attached to the primary rachis. Indeed, in morphology, these large structures seem very similar to structures generated by fusing into large pinnae of smaller, neighboring pinnules with simple, undivided, secondary veins. But the studied material shows no separation between smaller pinnules within the larger structures, therefore these large, pinnae-like structures cannot be named pinnae here. Givulescu (1999) admitted that the large laminar lobes can be in fact fused pinnules into larger pinnae. However, the pinnae term is widely used in recent and in fossil material; and, in the recent, involving in living species, the term pinna is exclusively used (Mirza 2007; Salino et al. 2014). The recent Pronephrium parishii from Bangladesh has reduced, rounded teeth (Mirza 2007), like those of Pronephrium gymnopteridifrons and P. megacuspe from China (Zhang 2012), strongly different from those of P. articulatum, P. lakhimpurensis and P. nudatum developed in Bangladesh (Mirza 2007) and in China (Zhang 2012).
Unger (1847) defined Polypodites stiriacum under the following diagnosis: “Fronde pinnata, pinnis lienaribus elongatis serratis, nervis secundariis e nervo primario angulo subacuto egredientibus pinnatis, ramulis alternatibus obliquis parallelis trans medium soriferis”. The type material was collected from Parschlug in Styria, Austria, and it is Miocene (Karpatian–early Badenian) in age (Kovar-Eder et al. 2004). The holotype showed in Unger (1847) in his Fig. 1 and plate 36 is a large fragment of an unipinnate frond with elongated–dentate pinnules, with marginal teeth of short–rounded apex, and with more acute apex which is rather symmetric (Figs. 2, 5) or slightly asymmetric (Fig. 4). Its connecting veins are strong and conspicuous, extremely alike with the Romanian Miocene material from Bozovici. Knobloch and Kvaček (1976) assigned their Bohemian Miocene material to Pronephrium stiriacum (Unger) Knobloch et Kvaček, making a new nomenclatorial combination. They also stressed the synonymy between Pronephrium Presl 1851 and Abacopteris Fee 1852, with Pronephrium having priority. Their material has elongated, large pinnules with symmetrical marginal teeth, similar to our Bozovici material. Givulescu (1996) described similar Pronephrium material under the name P. stiriacus, with falcate teeth along large pinnules and later (Givulescu 1999) under the name P. stiriacum. Pinnules were named pinnae by Givulescu (1996, 1999), and considered as a result from the fusion between regular pinnules. His material, which includes sori, was collected from Aninoasa and Vulcan (Petroșani Basin), and was studied in the collections of the Geological Institute of Romania in Bucharest (nos. P. 21224, P. 21225 from Aninoasa and P. 21228 from Vulcan). Givulescu (1986) only cited this species. Petrescu and Givulescu (1986) and Petrescu et al. (1997) cited and described Pronephrium stiriacum from the Petroșani Basin and from the Transylvanian Basin (Jac and Coruș). They considered the material as having dentate pinnules, not pinnae. Kvaček and Hurnik (2000) described Pronephrium stiriacum from the Miocene of the Czech Republic (Dobrcice locality), where it formed large leaf accumulations related to several swamp levels. The Czech material is also preserved in porcelanite, the leaves are fertile, with oppositely inserted pinnules, symmetrical marginal teeth and rather deep sinuses in between, very similar with our Bozovici Miocene material, although the connecting veins of the Czech material are not so prominent. Kvaček and Walther (1995, 1998) described Pronephrium stiriacum from the Oligocene tuffs of Suletice and Kundratice. Kvaček and Teodoridis (2007) only cited this species from the Czech Republic. Kovar-Eder et al. (2004) described the Miocene Pronephrium stiriacum from Austria, while Erdei and Wilde (2004) described a badly preserved fragment from Hungary, Oligocene in age. Kvaček et al. (2011) described Pronephrium stiriacum from the Miocene of France, with large pinnules and goniopterid venation. Hably (1985, 2013) considered the Miocene material as fused pinnules generating dentate pinnae, while Hably and Magyar (2013) only cited this species. Hably et al. (2015) described both fertile and sterile materials. Velitzelos et al. (2014) illustrated Pronephrium stiriacum with teeth apices very attenuated and rounded, almost entirely margined.