Ptychophylloceras (Semisulcatoceras) Joly, 2000

Barroso-Barcenilla, Fernando, Antunes, Miguel Telles, Brandão, José Manuel, Callapez, Pedro Miguel, Santos, Vanda Faria dos & Segura, Manuel, 2018, The d’Orbigny Palaeontological Collection of the National Museum of Natural History and Science, Lisbon, Portugal: Historical perspective and revision of Cretaceous Cephalopoda, Geodiversitas 40 (20), pp. 505-519 : 510

Subgenus Ptychophylloceras (Semisulcatoceras) Joly, 2000

Ptychophylloceras (Semisulcatoceras) semisulcatum (d’Orbigny, 1840) ( Fig. 2 H-J)

MATERIAL. — Two pyritized (and partially limonitized) internal moulds without written or glued indications. Original label: Nº 359/ Ammonites semisulcatus (d’Orb), Andar 17º Neocomiense, Terreno Cretaceo, Localidade Sisteron (Basses Alpes). See Figs 1D; 2K.

DESCRIPTION

Small-sized, compressed and involute ammonites with subrounded whorl sections. Highly bended and continuous venters and flanks, and narrow umbilici with arched walls. Ornamentation formed by five deep and aborally convex periumbilical constrictions per whorl. Notably complex suture lines with large folds in the external saddles showing a tetraphyllic tendency.

DISCUSSION

The specimen of d’Orbigny (1840: seemingly pl. 53, figs 4-5), originally collected from the Valanginian of Sisteron (Alpesde-Haute-Provence), France, and nowadays held at the MNHN with number MNHN.F.R00489, has been designated by Joly (2000) as the lectotype. The relatively high morphological variability of P. (S.) semisulcatum has allowed the proposal of several subspecies, such as diphyllum (d’Orbigny, 1840), without conspicuous periumbilical constrictions and recently studied in detail by Joly & Mercier (2012). The morphologically closest species is Ptychophylloceras (Semisulcatoceras) ptychoicum (Quenstedt, 1845) , but this Kimmeridgian-lower Berriasian form exhibits conspicuous external varici. In the last years, the Berriasian-Valanginian species P. (S.) semisulcatum , type of the subgenus, has been studied by Joly (1993, 2000), Reboulet (1996), Fischer & Gauthier (2006) and Joly & Mercier (2012), among others.

Suborder AMMONITINA Hyatt, 1889 Family HAPLOCERATIDAE von Zittel, 1884 Genus Neolissoceras Spath, 1923

Neolissoceras grasianum (d’Orbigny, 1840) ( Fig. 3 A-C)

MATERIAL. — Three internal moulds (two of them pyritized) without written or glued indications. Original label: Nº 357/ Ammonites grasanus (d’Orb), Andar 17º Neocomiense, Terreno Cretaceo, Localidade S. t Julien (Hautes Alpes). See Figs 1D; 3D.

DESCRIPTION

Small-sized, markedly compressed and moderately involute ammonites with subrectangular whorl sections, showing the maximum width at their external part. Slightly arched venter, conspicuous ventrolateral margin, nearly flat and divergent flanks, and wide umbilici with bended walls. Relatively complex suture lines showing a phylloid tendency and with wide saddles, being the first lateral one larger that the ventral. Ornamentation inexistent.

DISCUSSION

This Berriasian-Hauterivian species was firstly reported in Saint-Julien (seemingly, Saint-Julien-en-Beauchêne: Hautes- Alpes), France, by d’Orbigny (1850: 63). As highlighted by Avram & Grädinaru (1993) and Vasicek (2002), the morphologically closest species is Neolissoceras desmoceratoides Wiedmann, 1966 , but this Valanginian form exhibits less compressed section, arched flanks and wider umbilicus with sloping wall. In the last years, N. grasianum , type of the genus, has been studied by some authors, such as Reboulet (1996), Busnardo et al. (2003), Wippich (2003), Ettachfini (2004), Lukeneder (2004), Fischer & Gauthier (2006) and Joly & Mercier (2012).

Figures

FIG. 2. — Cretaceous nautiloid and ammonites of the d’Orbigny Collection of the National Museum of Natural History and Science (Museu Nacional de História Natural e da Ciência): A-C, Angulithes triangularis de Montfort, 1808 in oral (A) and lateral (B) views, and original label (C): Nº 459/Nautilus triangularis (Montf), Andar 20º Cenomaniense, Terreno Cretaceo,Localidade Fouras (Charente inf.re); D-G, Phylloceras (Hypophylloceras) tethys (d’Orbigny,1840) in ventral (D), lateral (E) and oral (F) views, and original label (G): Nº 360/Ammonites Tethys (d’Orb), Andar 17º Neocomiense, Terreno Cretaceo, Localidade Arredores de [environs of] Sisteron (Basses Alpes); H-K, Ptychophylloceras (Semisulcatoceras) semisulcatum (d’Orbigny, 1840) in ventral (H), lateral (I) and oral (J) views, and original label (K): Nº 359/Ammonites semisulcatus (d’Orb), Andar 17º Neocomiense, Terreno Cretaceo, Localidade Sisteron (Basses Alpes). Scale bar: 2 cm.

FIG. 3. — Cretaceous ammonites of the d’Orbigny Collection of the National Museum of Natural History and Science (Museu Nacional de História Natural e da Ciência): A-D, Neolissoceras grasianum (d’Orbigny, 1840) in ventral (A), lateral (B) and oral (C) views, and original label (D): Nº 357/Ammonites grasanus (d’Orb), Andar 17º Neocomiense, Terreno Cretaceo, Localidade S.t Julien (Hautes Alpes); E-G, Pleurohoplites (Pleurohoplites) renauxianus (d’Orbigny, 1840) in lateral (E) and ventral (F) views, and original label (G): Nº 464/Ammonites Renauxianus (d’Orb), Andar 20º Cenomaniense, Terreno Cretaceo, Localidade Mont-Blainville (Meuse); H-K, Acanthoceras rhotomagense (Brongniart, 1822) in oral (H), lateral (I) and ventral (J) views, and original label (K): Nº 463/Ammonites rhotomagensis (Lamarck), Andar 20º Cenomaniense, Terreno Cretaceo, Localidade Rouen (Seine inf.re). Scale bar: 2 cm.