Pérez and del Río—Danian Carditidae from Argentina Burckhardt (1902) identified this species as Cardita
morganiana Rathbun, 1875, a Brazilian taxon from Maria Farinha (Paleocene) and Pirabas (Miocene) formations (Penna, 1965; Tavora et al., 2010). The Brazilian species (White, 1887, pl. 8, figs. 18–21) differs from K. burmeisteri in having smaller and more robust shells with umbones placed more anteriorly, and in having more pronounced tripartition and the ribs sculptured with squamose nodes. Kalelia multicostata (Lamarck, 1806) (Cossmann and
1161 The only specimens found in Puesto Pircala, Malargüe
Pissarro, 1904, pl. 31, fig. 97–3; Sables de Bracheux) can be separated from K. burmeisteri by being larger, with a more horizontal dorsalmargin, anteriorly placed umbones, the posterior area sculptured with radial ribs of equal width, and by having more numerous radial ribs with better-developed tripartition over center of the valves. Kalelia burmeisteri is distinguished from K. pectuncularis
(Lamarck, 1806) (Chenu, 1842, pl. 2, fig. 8; Cossmann and Pissarro, 1904, pl. 31, fig. 97–2; Sables de Bracheux) by its smaller size, sloping dorsalmargin, subcentrally placed umbones, and fewer and wider radial ribs.
Other Danian records of Carditidae
Some records of Danian carditids from Argentina have an uncertain taxonomic status and affinities and they are reviewed below.
‘Cardita’ morganiana and ‘Cardita’ beaumonti.—(Fig. 6.3; MLP 10220a–d). These two species have been mentioned frequently in the literature of the Paleocene from Argentina (Behrendsen, 1891; Burckhardt, 1900, 1902; Windhausen, 1918, 1931; Weaver, 1927, 1931; Gerth, 1935; Fossa Mancini, 1938a, 1938b). As stated above, ‘Cardita’ morganiana Rathbun, 1875
is a Cenozoic Brazilian species that is possibly related to Baluchicardia Rutsch and Schenck, 1943. ‘Cardita’ morganiana was cited for the first time in Argentina from Puesto Pircala (Malargüe, Roca Formation, Mendoza Province) (Behrendsen, 1891), based on internal molds. These outcrops were assigned a Maastrichtian age by Parras et al. (1998). Burckhardt (1902) indicated the presence of ‘C.’ morganiana in thetypeareaof the Roca Formation,which is of earlyDanian age according to delRío et al. (2011). Weaver (1927, 1931) mentioned the presence of ‘Cardita’
beaumonti (=Baluchicardia beaumonti) in General Roca rocks. Baluchicardia beaumonti comes from Maastrichtian and Danian beds of northwestern India and Pakistan (Calcaire jaune de la chaine d’Hala, Sind Region), and North Africa (d’Archiac and Haime, 1854; Rutsch, 1936; Heaslip, 1968). According to Fossa Mancini (1938a), this species was mistakenly mentioned by Weaver (1927) because the author followed the ideas of Fritzsche (1919), who synonymized ‘C.’ morganiana with ‘C.’ beaumonti. Fossa Mancini (1938a) concluded that this synonymy is invalid. The specimens from the area of General Roca (MLP
15294a–f) were used for erecting the species ‘C.’ burmeisteri (=Kalelia burmeisteri) and ‘C.’ iheringi (both discussed below) by Böhm (1903).
(‘Cardita’ morganiana of Behrendsen, 1891 and Burckhardt, 1900) are small internal molds (MLP 10220a–d) with triangular outlines and very rounded margins. The absence of internal characters prevents generic and specific assignment. Casadío (1994) considered them to be juveniles of Venericardia ameghinorum (Ihering, 1907), but Parras et al. (1998) placed them in V. iheringi (Böhm, 1903). Venericardia iheringi is another species based on internal molds, and the Malargüe casts are very similar to this species. In this paper we accept the assignment by Parras et al. (1998), and assign the specimens MLP 10220a–cto ‘Venericardia’ iheringi. In this way and according to Fossa Mancini’ (1938b), the
presence of ‘Cardita’ morganiana and ‘C.’ beaumonti in Argentina is rejected.
‘Venericardia’ iheringi (Böhm, 1903).—(Fig. 6.4, 6.5; MLP 15294b-e [Syntypes]; MLP 4298, 5377, 5387, 5517, 5125, 7625, 8866, 8955, 9455, 9726, 10506; MACN-Pi 356; CPBA 6405, 6408; MHNSR:Pi 1010, 1385, 1386, MACN-Pi 5750, MACN-Pi 5754, MACN-Pi 5749, MACN-Pi 5745). As in the previous case, this species was erected by Böhm (1903) based
on the internal molds described by Burckhardt (1902, p. 219, figs. 2–6) from General Roca (Danian, Roca Formation). Ihering (1907) included it within Venericardia, but this assignment is not confirmed because this species lacks hinge and external sculpture, the most valuable characters required for a more precise generic placement among carditids. ‘Venericardia’ iheringi has small to medium-sized shells with subtriangular to subquadrate outlines, rounded margins, prominent and very convex umbones placed subcentrally, and 21–22 radial ribs that are wider than their intercostals spaces. It is distinguished from casts of Kalelia burmeisteri (Böhm, 1903) by its smaller size with more rounded margins and by the absence of an umbonal- ventral carina. None of the other species from Roca Formation has the set of characters present in ‘V.’ iheringi. Ihering (1907) mentioned a variation of this species, which he named Venericardia iheringi var. boehmi, with a more subquadrate outline, but it is difficult to differentiate from other specimens. Therefore, ‘Venericardia’ iheringi is a species with uncertain affinities and we cannot assign it to any of the other species described from the Roca Formation.
Venericardia ameghinorum (Ihering, 1907).—(MACN-Pi 340 [Holotype], 5213; CPBA 6406, 6409, 6410, 6412; MLP 5006, 6315, 7285, 7737, 8951, 8956, 10503, 10504, 10505; MHNSR:Pi 1398). Venericardia ameghinorum was erected by Ihering (1907) based on internal molds from General Roca (Roca Formation). This species has elongated shells that are easily distinguishable from other Paleocene carditid species. The elongate outlines with a sinuous ventral margin, and strongly recurved and separated orthogyrous umbones, placed this species within the genus Arca Linnaeus, 1758 (family Arcidae), as already mentioned by del Río et al. (2011).
cf. ‘Cyclocardia’ sp. (del Río et al., 2007).—(GHUNLPam 22888, 22897–22900). Del Río et al. (2007) described cf. Cyclocardia sp. from the Roca Formation in Cerros Bayos (Danian, La Pampa Province), based on four internal molds of
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