Bollettino della Società Paleontologica Italiana, 44 (2), 2005, 81-115. Modena, 30 settembre 200581

Early Pliensbachian ammonites from the Furlo Pass (Marche, Italy): two new faunas for the middle-western Tethys

Federico VENTURI, Carlo NANNARONE & Massimiliano BILOTTA

F. Venturi, Dipartimento di Scienze della Terra, Università degli Studi di Perugia, Piazza Università 1, I-06123 Perugia, Italy; [email protected] C. Nannarone, Dipartimento di Scienze della Terra, Università degli Studi di Perugia, Piazza Università 1, I-06123 Perugia, Italy. M. Bilotta, Dipartimento di Scienze della Terra, Università degli Studi di Perugia, Piazza Università 1, I-06123 Perugia, Italy; [email protected]

KEY WORDS - Ammonites, Taxonomy, Biostratigraphy, Tethys, Early Jurassic.

ABSTRACT - Fu1 and Fu2 faunas, represented by the spathic lumachella horizons of the Grilli Quarry (Furlo Pass, Umbria- Marche Apennines), contain two highly biodiversified assemblages. They follow chronologically the “Venturi ’78” bed from the Pallareto Quarry (Catriceras catriense bioevent), which is considered the first post-Sinemurian record to be found in the Apennines: as a whole, these three faunas characterize the lower part of the Early Pliensbachian (Carixian) in our area. The material collected at the Furlo Pass enabled us to recognize an unexpected wealth of forms, including some completely new taxa. Within the Psiloceratida (order comprising the taxa traditionally placed in the Lytoceratina and Ammonitina), the new family Holcolytoceratidae is proposed here for Audaxlytoceras together with Holcolytoceras. Among the Eoderoceratoidea, we describe the new species Omoderoceras latispira (a Paramicroderoceratinae with monospinate inner stage, formerly found in the “Venturi ’78” bed), and we note the discovery of the first Apennine ammonoid ascribable to Apoderoceras. The presence of this typically Boreal or sub-Boreal genus has been adopted in the stratotype section (GSSP) of Wine Haven (England) to recognize the base of the Pliensbachian: the apparently “delayed” occurrence of this taxon in our area causes difficulties and inaccuracies in the correlation between the standard zonal scheme and the one used in the Apennines. Remaining within the Eoderoceratoidea, we give a better definition of the Apennine genera Caleites and Furlites. Starting from the description of several specimens attributed to Catriceras cf. campiliense, the differences between Catriceras and Tropidoceras are exhaustively considered. These characters allow clear distinction of the two genera, which cannot be considered synonyms. With regard to the Oxynoticeratidae, we recognize the new species Radstockiceras fastigatum in the Fu1 fauna: the abundance of material enabled us to describe its ontogenetic development. Particular emphasis is given to the new small-sized genus Pelingoceras, described for the new species P. pseudocarinatum: its really unusual features, including the appearance of the peristome, make its suprageneric position uncertain. A doubtful classification (this time at suprafamiliar rank) is also indicated for Sinuiceras: the new family Sinuiceratidae is proposed here for this genus, together with the Tunisian forms erroneously reported as Gorgheiceras. All these taxonomic observations allow a wide survey of the Apennine ammonite faunas for a time interval which is still somewhat incompletely known in many areas (either Tethyan and sub-Tethyan, or Boreal and sub-Boreal). The biodiversity of our fossil assemblages seems unmatched with regard to coeval sections of other areas. Furthermore, it offers solid foundations to the local zonation, the use of which is necessary because is not possible or not practical to utilize the Early Pliensbachian standard zonal scheme. Among the several characteristic and reliable taxa of our faunas, the best is probably Catriceras; due also to the clear distinction of this genus from Tropidoceras, we propose a new biostratigraphic unit: the Catriceras Interval Biozone. It marks the first part of the Pliensbachian in the Apennines, and replaces the old “Tetraspidoceras quadrarmatum” Oppel Biozone, which we intend to abandon. Compared to the Echioceras raricostatum Zone (late Sinemurian) ammonoids, the genus Catriceras, together with the numerous associated forms, is a good representative of the faunal change related to the Sinemurian-Pliensbachian transition. The zonal scheme here proposed is therefore more precise and effective than those generally adopted till now for the biostratigraphy of the Mediterranean Tethys. We currently feel that our assemblages may represent a paleobiogeographic entity separate from other neighbouring regions. It seems that, in the Neotethys, only a discontinuous faunal exchange occurred between the “Alpine” sector and the westernmost one. Considering also the sedimentary discrepancies (both quantitative and qualitative), this partial isolation and the related faunal differences have repercussions on the correlatability of the biostratigraphic boundaries. Notwithstanding these limitations, the assemblages studied in the present paper seem to support the idea that the faunal renewal connected with the Sinemurian-Pliensbachian boundary was mainly triggered by a change in the paleogeographic setting (seaway opening) more than by a biological crisis in the strict sense.

RIASSUNTO - [Ammoniti del Pliensbachiano inferiore del Passo del Furlo (Marche, Italia): due nuove faune per la Tetide centro- occidentale] - Le faune ad ammoniti Fu1 e Fu2, rappresentate dai livelli di lumachella spatica della Cava Grilli (Passo del Furlo, Appennino umbro-marchigiano) contengono due associazioni ad elevata biodiversità. Esse risultano cronologicamente successive al livello “Venturi ’78” della Cava del Pallareto (bioevento a Catriceras catriense), che è considerato la prima documentazione post- sinemuriana dell’Appennino finora trovata: complessivamente, queste tre faune caratterizzano la parte bassa del Pliensbachiano inferiore (Carixiano) nella nostra area. Lo studio delle lumachelle Fu1 e Fu2 offre l’occasione per importanti considerazioni tassonomiche e biostratigrafiche, consentendo un notevole progresso delle conoscenze sul Pliensbachiano inferiore nella Tetide mediterranea e sulle sue faune ad ammoniti. A questo proposito, il materiale raccolto al Passo del Furlo ha permesso di riconoscere un’insospettata ricchezza di forme, che includono alcuni taxa totalmente nuovi.

ISSN 0375-7633 82 Bollettino della Società Paleontologica Italiana, 44 (2), 2005

Nell’ambito degli Psiloceratida (ordine che comprende i taxa tradizionalmente collocati nei Lytoceratina ed Ammonitina), vengono esposte le differenze fra Audaxlytoceras ed Aegolytoceras; per quest’ultimo genere, insieme ad Holcolytoceras, viene inoltre proposta la nuova famiglia Holcolytoceratidae. I rapporti di questo gruppo con altri dello stesso rango sono difficili da stabilire, perché le informazioni sulle relazioni filetiche e sulla sistematica dei “litoceratini” sono ancora molto scarse, incomplete e lacunose (soprattutto per quanto riguarda Hettangiano ed il Sinemuriano inferiore). Principalmente per lo stesso tipo di motivi, è posta in dubbio l’attribuzione alla famiglia Ectocentritidae dei Peltolytoceratinae (Peltolytoceras, Exomiloceras e Galaticeras, a cui va aggiunto il genere tunisino di recente descrizione Castanyiceras). Sembra poi ragionevole escludere che esistano rapporti di stretta parentela fra Galaticeras e Bouhamidoceras, soprattutto perché i due generi presentano un diverso sviluppo ontogenetico, e non mostrano caratteri comuni veramente esclusivi. Fra gli Eoderoceratoidea, va segnalata la descrizione della nuova specie Omoderoceras latispira (un Paramicroderoceratinae a stadio interno monospinato già rinvenuto nel livello “Venturi ’78”), ed inoltre il ritrovamento del primo ammonoideo appenninico ascrivibile ad Apoderoceras. La comparsa di questo genere tipicamente boreale o sub-boreale è stata adottata nello stratotipo (GSSP) di Wine Haven (Robin Hood’s Bay, Yorkshire, Inghilterra) come principale criterio biostratigrafico per riconoscere la base del Pliensbachiano, ma il “ritardo” con cui esso sembra presentarsi nella nostra area causa difficoltà ed imprecisioni nella correlazione fra lo schema zonale standard e quello adottato in Appennino. Sempre all’interno degli Eoderoceratoidea, è stata possibile la miglior definizione dei generi appenninici Caleites e Furlites, per i quali vengono soprattutto precisate le relazioni con le piccole forme tetidee medio-liassiche normalmente ascritte a Gemmellaroceras. Se per Caleites le eventuali somiglianze con quest’ultimo sembrerebbero dovute a convergenza, per Furlites si può ipotizzare un’affinità maggiore, ed in effetti esso potrebbe rappresentare un sottogruppo distinto da quello dei Polymorphitidae più tipici (Polymorphites, Platypleuroceras, Uptonia, Dayiceras). Partendo dal ritrovamento di numerosi esemplari attribuiti a Catriceras cf. campiliense, vengono valutate in maniera esauriente le differenze di Catriceras e Tropidoceras, riguardanti avvolgimento, ricoprimento dei giri, sezione della spira, forma dell’area ventrale, aspetto della carena, andamento dell’ornamentazione, linea di sutura, distribuzione stratigrafica e geografica. Tali caratteri permettono di separare chiaramente i due generi, che non possono venir considerati sinonimi. Viene inoltre motivata la collocazione di Catriceras e Tropidoceras nella sottofamiglia nominale dei Tropidoceratidae, il che lascerebbe Acanthopleuroceras in un taxon per ora monotipico (gli Acanthopleuroceratinae). Riguardo agli Oxynoticeratidae, nella fauna Fu1 è stata riconosciuta la nuova specie Radstockiceras fastigatum, caratterizzata da area ventrale tettiforme e spira con brusco cambiamento d’inclinazione a circa metà del suo lato; l’abbondanza di materiale ci ha consentito di seguirne lo sviluppo ontogenetico fin dal diametro di circa 5-6 mm. Nell’associazione Fu2 R. fastigatum sembra assente, ed il genere è rappresentato da alcuni piccoli individui la cui attribuzione specifica non è attualmente precisabile (Radstockiceras sp.). Particolare risalto va dato al nuovo genere di piccola taglia Pelingoceras, descritto per la nuova specie P. pseudocarinatum: le sue caratteristiche veramente insolite, compreso l’aspetto del peristoma, ne rendono incerta l’attribuzione sopra-generica. Di collocazione dubbia (ma stavolta a livello sopra-familiare) è anche Sinuiceras: per esso, e per le forme tunisine erroneamente segnalate come Gorgheiceras, viene proposta la nuova famiglia Sinuiceratidae. L’interesse biostratigrafico di tutte queste osservazioni tassonomiche è notevole: esse permettono infatti di delineare il vasto panorama delle faune ad ammoniti in Appennino per un intervallo di tempo la cui conoscenza in molte aree tetidee o sub-tetidee (Italia settentrionale, Spagna meridionale, Marocco, Tunisia, Albania, Ungheria, ecc.), ma anche boreali e sub-boreali (Francia, Germania, ecc.) è tuttora piuttosto incompleta. La biodiversità delle nostre associazioni fossili non sembra avere pari in sezioni coeve di altre aree, ed offre solide basi alla zonazione locale, il cui utilizzo è reso necessario dall’impossibilità o impraticità nell’uso dello schema zonale standard per il Pliensbachiano inferiore. Fra i vari taxa caratteristici ed affidabili di cui disponiamo, il migliore è probabilmente Catriceras. La sua più chiara differenziazione da Tropidoceras ci ha portato a proporre una nuova unità biostratigrafica che individua la prima parte del Pliensbachiano in Appennino, la Biozona ad intervallo a Catriceras, in sostituzione di quella oppeliana a “Tetraspidoceras quadrarmatum” (il cui uso intendiamo abbandonare). Il genere Catriceras è una delle novità biologiche più significative rispetto agli ammoniti della Zona ad Echioceras raricostatum (Sinemuriano superiore): esso, insieme alle numerose forme associate, ben rappresenta il cambiamento faunistico legato al passaggio Sinemuriano-Pliensbachiano. Lo schema zonale qui proposto risulta quindi più preciso ed efficace di quelli generalmente usati finora per la biostratigrafia della Tetide mediterranea. Ciò è particolarmente evidente nei confronti della zonazione definita per la Cordigliera Betica (Spagna meridionale), la cui accuratezza non appare sufficiente, soprattutto perché la sua base non è ben documentata, ed il suo primo marker (Gemmellaroceras aenigmaticum) non è del tutto adeguato, dato che nella nostra area esso si ritrova solo a partire dalla seconda biozona del Pliensbachiano inferiore (Zona a Miltoceras sellae). Le notevoli differenze tra le faune pliensbachiane appenniniche e quelle più o meno coeve di altre aree forse sono parzialmente imputabili alla scarsità di studi e/o ritrovamenti, ma attualmente abbiamo l’impressione che le nostre associazioni possano rappresentare un’entità paleobiogeografica separata da altre regioni vicine (ad esempio Spagna, Nord Africa). I dati biostratigrafici e le ricostruzioni paleogeografiche di cui disponiamo per la porzione centro-occidentale della Neotetide (Tetide Alpina Mediterranea o Tetide Mediterranea) non ci permettono tuttavia di valutare appieno l’importanza di tale separazione. Sembra comunque che, in questa regione, lo scambio faunistico tra il settore “alpino” (comprendente Austroalpino, Alpi calcaree meridionali, Appennino, Sicilia e placca apula; forse anche Albania e Grecia ionica) e quello più occidentale (Cordigliera Betica e Nord Africa) sia stato discontinuo. Considerando anche il divario di sedimentazione (quantitativo e qualitativo) esistente fra le varie parti della Neotetide centro- occidentale, questo parziale isolamento e le differenze faunistiche ad esso imputabili si riflettono sulla correlabilità dei limiti biostratigrafici, sia rispetto alla zonazione standard boreale e sub-boreale che nei confronti degli schemi stabiliti all’interno delle stessa Tetide. Nonostante queste limitazioni, le associazioni studiate nel presente lavoro sembrano appoggiare l’idea che il rinnovamento faunistico in corrispondenza del limite Sinemuriano-Pliensbachiano sia stato “innescato” principalmente da una variazione paleogeografica (apertura di passaggi marini) più che da una crisi biologica in senso stretto.

FOREWORD of this time interval is now possible thanks to the new discoveries at the Grilli Quarry (Furlo Pass), where This research is justified by the need to provide the succession is significant, although represented by detailed knowledge on the ammonite faunas several lumachella layers arranged without a clear characterizing the Early Pliensbachian biozones in the stratigraphic continuity. In this paper the first two faunal Umbria-Marche Apennines. A more detailed treatment assemblages (Fu1 and Fu2) of the Grilli Quarry section F. Venturi, C. Nannarone, M. Bilotta - Liassic ammonite faunas from the Apennines 83 are examined, while the third one (Fu3) will be the subject of a forthcoming publication. Recent studies on the biostratigraphic position of the “Venturi ’78” bed (Pallareto Quarry, Mount Acuto; Fig. 1) lead us to hypothesize that the Catriceras catriense bioevent should be regarded as the chronologically oldest Pliensbachian documentation of the Apennine (Venturi & Bilotta, 2001; Venturi et al., 2004). The ammonite faunas of the spathic Fu1 and Fu2 lumachellas of the Furlo Pass support this opinion, being composed of several undoubtedly Pliensbachian genera and species (including some new forms) not present in the “Venturi ’78” bed, but nevertheless attributable to the first Pliensbachian biozone. On this subject, we should remember that the biostratigraphic data of “Venturi ’78” bed and of Fu1 and Fu2 lumachellas are also important in outlining the significance of the faunal renewal related to the Sinemurian-Pliensbachian boundary. With regard to this chronostratigraphic transition, information in the Tethyan or sub-Tethyan areas outside the Apennine territory (northern Italy, southern Spain, Morocco, Tunisia, Albania, but also Hungary, etc.), has up to now proved generally scarce, being pertinent to mainly incomplete and condensed successions (Géczy, 1976; Braga et al., 1982, 1984; Dommergues & Géczy, 1989 El Hariri et al., 1996; Dommergues et al., 1997b, 2000; Lachkar et al., 1998; Rakús & Guex, 2002). Also for the majority of Boreal and sub-Boreal regions (France, Germany, etc.) the knowledge of the base of the Pliensbachian is still somewhat imperfect (Dommergues & Meister, 1992; Dommergues, 2003). The only section which seems to offer sufficient data about this issue is Wine Haven (Robin Hood’s Bay, Yorkshire, England), and this is one of the reasons why it was recently chosen to formalize the stratotype (GSSP) of the Sinemurian- Pliensbachian boundary (Hesselbo et al., 2000; Meister et al., 2003). As already expound in another paper (Venturi et al., 2004), such a GSSP, essentially based on the appearance of Apoderoceras Buckman and/or Fig. 1 - Geographic location of the Pallareto Quarry, Bosso and Tetraspidoceras quadrarmatum (Dumortier) does not Furlo Pass (Grilli Quarry) sections. allow precise correlations outside the Boreal Paleoprovince. However, the need for detailed comparisons between Boreal and Tethyan successions remains, and the ammonite faunas discussed in the present research demonstrate this requirement still further. as a reference in local correlations. In this scheme, the index species for the first Early Pliensbachian biozone was initially designated Tetraspidoceras quadrarmatum, THE EARLY PLIENSBACHIAN BIOZONAL but was subsequently referred to as “T. SCHEME IN THE MIDDLE-WESTERN TETHYS quadrarmatum”, because it was noted (Dommergues et al., 2000; Venturi et al., 2004) that the Apennine Since the use of a standard zonal scheme in the specimens to which this name was applied does not Tethyan area is either impossible or impractical, the belong to the genus Tetraspidoceras Spath. recognition of the lowermost biostratigraphic interval Integrating the new information presented here with for the Early Pliensbachian (equivalent to the basal previous studies on other Apennine localities (Venturi, portion of the north-west European Jamesoni 1978; Faraoni et al., 1996; Venturi & Bilotta, 2001), Chronozone) is a problem resolved in different ways we are now able to delineate a first correlation between by various Authors. the Bosso River (Bosso: beds 39-46; Stirpeto: beds 32- On the basis of Mediterranean taxa (and in particular 105), Pallareto Quarry (“Venturi ’78” bed: Catriceras on data from the Bosso River section), Faraoni et al. catriense bioevent) and Furlo Pass (Fu1 and Fu2 faunas) (1996) worked out a zonation for the Umbria-Marche sections (Fig. 2). With reference to these sections, and Apennines (central Italy), which proved itself useful in accordance with the recommendations of the 84 Bollettino della Società Paleontologica Italiana, 44 (2), 2005

International Stratigraphic Guide (Salvador, 1994), we biostratigraphic interval). We therefore intend to propose to redefine the first Early Pliensbachian abandon the use of the “T. quadrarmatum” Oppel Apennine biozone, or rather, to describe a new one, Biozone, replacing it with the new Catriceras Interval roughly equivalent to it (that is, covering an analogous Biozone: its base is defined by the appearance of

Fig. 2 - Short-distance biocorrelation among three lower Pliensbachian sections of the Umbria-Marche Basin. The Bosso River section (in the middle) is the most extended one, and it corresponds to the Corniola of complete successions: this is the only of the three presented sections that contains late Sinemurian faunas (bed 15: Paltechioceras; bed 16: Vicinodiceras and Plesechioceras). The Pallareto Quarry section (on the left) can be considered a “transitional” term between complete successions and incomplete ones, and contains three encrinitic layers. The Furlo Pass section (on the right) is an incomplete and reduced succession of structural high. The “Venturi ’78” bed of the Pallareto Quarry (Catriceras catriense bioevent) should correspond to the beds 34-40 of the Bosso section, while the Fu1 lumachella from the Furlo Pass is supposed to be more or less contemporaneous to beds 42-46. The Fu3 bed (Miltoceras nov. sp. and new polymorphitid fauna), probably represents the base of the Miltoceras sellae Zone, and therefore it is inferred to precede the assemblage located on the top of the bed 17 of the Pallareto section. F. Venturi, C. Nannarone, M. Bilotta - Liassic ammonite faunas from the Apennines 85 ammonites of the genus Catriceras Venturi, while its THE MATERIAL STUDIED top is determined by the first occurrence of ammonites belonging to Miltoceras Wiedenmayer. This choice PROVENANCE AND PRESERVATION enables a more effective characterization of the first Pliensbachian biostratigraphic subdivision in the The ammonites that are the subject of this paper Apennines, while keeping a concept similar enough to were found in the calcareous rocks belonging to the the original (Faraoni et al., 1996). We deem the genus lithostratigraphic unit called “Corniola”, and come from Catriceras a better index taxon for this time interval, two out of the three main spathic lumachellas (named since it is fairly abundant and can be recognized without Fu1, Fu2 and Fu3) recognized at the Furlo Pass (Grilli too many difficulties (as explained in the systematic Quarry). Their facies is characteristic of reduced or section of the present paper). Moreover, this taxon is a condensed successions (ramp or Calcare Massiccio good representative of the faunal change related to the sensu lato facies, sometimes referred as “Corniola Sinemurian-Pliensbachian transition, being one of the massiccia”, i.e. “massive Corniola”), without regular most meaningful biological novelties compared to the stratification and sometimes encrinitic. Fossils occur Echioceras raricostatum Zone (late Sinemurian) in a very localized area, and they are restricted to sub- ammonite assemblages. lenticular bodies, where very often the material looks Basing on the faunal content of the reference fragmented (but never reworked), without evident sections, the most characteristic forms which can be sorting or orientation. The bioclasts (for the most part found associated to the index taxon of the Catriceras ammonites) appear to float in an abundant matrix, biozone are: Galaticeras Spath, Radstockiceras which is almost always recrystallized, and show internal Buckman, Furlites Venturi & Ferri, Caleites Venturi & cavities frequently filled by druse cements, but without Ferri, Eoderoceratidae with a monospinate stage (e.g. evident geopetal structures. The features of these Omoderoceras Venturi, Nannarone & Bilotta), lumachellas seem indicative of sedimentation by Phricodoceras gr. taylori (Sowerby); at the base of the discontinuous episodic inputs, originated as markedly Zone, rare elements with Sinemurian affinity (such as canalized gravitative deposits (debrites). In all Paramicroderoceras Dommergues, Ferretti & Meister) probability, the material constituting these debrites came can occur, whereas Sinuiceras Venturi & Ferri is typical from a more elevated portion of the sea-bottom, and, of the uppermost part. after rather short transport, it was deposited in a slope Judging from the assemblages reported in the most environment without the contribution of waves or recent literature, the Catriceras biozone also appears currents. to be documented in Argentina (Arroyo Las Chilcas Although the examined assemblages (Fu1 and Fu2) section: Hillebrandt, 1990, 2002 and personal are not superimposed in the same outcrop portion, they communication), southern Albania (Lefterochori were found at a short distance from each other within section: Dommergues et al., 2000), Morocco (Jebel- the same quarry: it is not possible to specify with Bou-Hamid section: Lachkar et al., 1998) and perhaps certainty the reciprocal stratigraphic relations, but basing Tunisia (Djebel Oust-Est section: Rakús & Guex, 2002), on their faunal content we suppose that they represent in addition to the Apennine sections. two consecutive (not coeval) time slices (Fig. 3).

Fig. 3 - Early Pliensbachian correlation hypothesis among the standard zonation and three different Tethyan schemes. Note that, in Mediterranean regions, the highest biostratigraphic resolution for the lower part of this time interval is provided by the zonation presented in this paper. 86 Bollettino della Società Paleontologica Italiana, 44 (2), 2005

The lumachellas are for the most part made up of or involution index (u/d), whorl shape or flattening index ammonites, and the amount of recovered individuals is (w/h), height ratio (h/d), width ratio (w/d). Estimated very high (in all, over 300 more or less complete values are preceded by the symbol ~. specimens and fragments). These are internal moulds composed of calcite crystals: sometimes they completely fill the chambers, but on other occasions Subclass AMMONOIDEA Zittel, 1884 they have a drusy fabric, which leaves an empty space Order PHYLLOCERATIDA Arkell, 1950 inside the shell; in the largest specimens (which are Family PHYLLOCERATIDAE Zittel, 1884 found relatively complete only in the Fu1 lumachella) Subfamily PHYLLOCERATINAE Zittel, 1884 the phragmocone can also be filled by micrite. At times a pseudo-test is preserved, formed by several calcitic Genus Phylloceras Suess, 1865 veils which probably trace the original arrangement of the inner nacreous layer. In some forms of the Fu1 Type species - Ammonites heterophyllus Sowerby, lumachella, the recrystallized pseudo-test appears as a 1820. very thick incrustation, certainly thicker than the original test, which summarily reproduces whatever Remarks - Several middle-Liassic forms ascribed ornamentation was present. to this genus show different features compared to the The suture line is often visible (at least in “typical” Toarcian species linked up with P. transparency), even when the mould is covered by one heterophyllum. More detailed studies will be needed to or two of the innermost test layers. However, when appraise the taxonomic significance of these the filling is a mixture of micrite and calcite, a sort of differences, which may be important to understand the septal “selection” happens: this means that lobes and purport of the paleobiologic and paleoenvironmental saddles stand out very clearly in a vast gamut of soft change due to the Toarcian anoxic event. colours (from white to red), or with a contrast between white and grey tones. On other occasions, calcite Phylloceras meneghinii Gemmellaro, 1874 completely effaces the suture line: in this case, if the Figs. 4a-b; Pl. 1, figs. 1a-b body chamber does not show morphological peculiarities (ornamentation or other), it cannot be 1874 Phylloceras Meneghinii GEMMELLARO, p. 102, pl. 12, fig. distinguished from the phragmocone. 23. 1884 Phylloceras Meneghinii Gemmellaro - GEMMELLARO, p. 8, pl. 2, figs. 13-17. 1899 Phylloceras Meneghinii Gemmellaro - FUCINI, p. 150, pl. 29, fig. 7. SYSTEMATIC DESCRIPTIONS Lectotype - The specimen n. 5/1 (with a half whorl The remarkable diversity of the forms discussed in of preserved body chamber), from the original the following paragraphs (including some taxa with an collection of Gemmellaro (1884, pl 2, figs. 13-15), ambiguous and/or problematic systematic position) lead housed in the Geologic Museum “G.G. Gemmellaro” us to consider critically the high-rank classification of (Geology and Geodesy Department of the Palermo the Jurassic ammonoids, i.e. their arrangement at the University), is here designated as lectotype. hierarchical levels of superfamily, suborder and order. In this paper it is impossible for us to deal exhaustively with this issue, which will be discussed in a future research: for the moment, we can merely say that the taxonomic scheme here adopted conforms in substance to the opinions of Guex (1982, 1987), Taylor (1998) and Dommergues (2002). For some taxa, comparison with the original Gemmellaro (1884) collection coming from the Rocche Rosse near Galati (Messina, Sicily) was necessary. Regarding this material, housed in the “G.G. Gemmellaro” Geologic Museum (Geology and Geodesy Department of the Palermo University), one of us (Venturi) some time ago drafted a revision work (still unpublished) where the lectotypes and paralectotypes of many species were defined: some of these designations are now formally adopted here. For the terminology used in the descriptions in this paper, see Venturi et al. (2004) and references therein. For a selected number of exemplars of most species the following biometric parameters are given, stated in Fig. 4 - Suture lines of Phylloceras meneghinii Gemmellaro; magnified about x 4; millimetres (for linear measurements) or as adimensional a) specimen Fu1Phy5, drawn at a diameter of about 18 mm; numbers (for ratios): diameter (d), umbilical diameter b) specimen Fu1Phy1, drawn at a diameter of about 30 mm (u), whorl height (h), whorl width (w), umbilical ratio (drawings by F. Venturi). F. Venturi, C. Nannarone, M. Bilotta - Liassic ammonite faunas from the Apennines 87

Material - Ten middle-large sized specimens. Genus Partschiceras Fucini, 1920

Measurements - Type species - Ammonites striatocostatus Meneghini, Number d u h w u/d w/h h/d w/d 1853. Fu1Ph01 37.9 5.3 22.1 19.30 0.14 0.87 0.58 0.51 Fu1Ph04 15.0 1.9 7.9 7.20 0.13 0.91 0.53 0.48 Diagnosis - More or less compressed shell, with Fu1Ph06 12.0 1.5 6.5 5.50 0.13 0.85 0.54 0.46 Fu1Ph08 11.3 1.3 5.9 5.20 0.12 0.88 0.52 0.46 high sub-elliptic whorl section. Fu1Ph09 10.9 1.0 6.0 5.20 0.09 0.87 0.55 0.48 Very characteristic ribs are clearly visible on the test, but not on internal moulds (which sometimes Diagnosis - Very involute and broad shell, with appear smooth); they are confined to the outer part of elevated degree of whorl overlapping (about 80%). The the flank, from which they cross the ventral area whorl has a rapid height increase (every whorl is nearly without interruption, and seem to be originated by three times as high as the preceding one), with section bundling and rising of phylloceratine lyrae. showing the maximum thickness in its lower part. The suture line has some characters which can be Rounded umbilical edge; narrow ventral area. observed also in other Phylloceratida, but they are Nearly smooth test (when present), but, if the combined in a unique and distinctive way: E shorter preservation is good enough, very feeble striae (or than L, U2 nearly as long as L, triphyllic LS1 saddle growth lines) can be observed: at first, they form a with backward inner leaf; the relative proportions of forward-concave curve, then, they bend backward and E, L and U2 lobes are involved by interspecific and become nearly rectiradiate, crossing the ventral area, sometimes intraspecific variability (also in relation to where longitudinal lines can be glimpsed. the ontogenetic stage). Suture line moderately indented: E is about two- third of L, which is markedly asymmetric; U2 is nearly Remarks - The indications on type species and as long as L; diphyllic ES saddle and triphyllic LS1 publication year of the genus here reported follow the saddle with inner leaf in a moderately backward detailed revision by Fantini Sestini (1971). position. Stratigraphic distribution - The genus is surely Remarks and comparisons - This is a well- present in the middle Lias, but it occurs already in the characterized species for the very broad whorl with early Sinemurian (Venturi & Nannarone, 2002). On the sub-ellipsoidal outline, the funnel-shaped umbilicus and other hand, there is no safe data about the existence of the ventral area, which is rather narrow for a species strictly ascribable to this taxon after the Lias representative of Phylloceras. The most similar taxon (from Dogger-Malm to the Barremian), as instead appears to be Phylloceras hebertinum (Reynès), from reported by some Authors, including Arkell et al. (1957). which P. meneghinii differs principally for the peculiar whorl section. This affinity has been already suggested Partschiceras cf. retroplicatum (Geyer, 1893) by Gemmellaro (1884), who gave a very good Figs. 5a-b description of his species, also with regard to the suture line. 1893 Phylloceras retroplicatum GEYER, p. 45, pl. 6, figs. 3-4, 6 In the literature P. meneghinii is quite well-known: (non 5). it was rightly interpreted for instance by Negri (1933), Cantaluppi & Savi (1968) and Fantini Sestini (1974). Wiedenmayer (1977) devoted to it an ample treatment, with a very rich synonymy list, thus apparently attributing to the taxon an exceedingly wide morphological variation ambit. Nevertheless, the Author do show a correct interpretation of its main features, as can be seen by the figures of three incomplete specimens from Besazio. In the present paper the aspect of the striae of this species is described for the first time, and we must underline that they are rather different compared to those of the typical Toarcian Phylloceras.

Stratigraphic distribution - The species seems to be present throughout the middle Lias, as far as the first Toarcian biozone, as proved by citations and related figures of Meneghini (1881), Negri (1933), Cantaluppi & Savi (1968), Fantini Sestini (1974), Wiedenmayer (1977). Fig. 5 - Partschiceras cf. retroplicatum (Geyer), specimen Fu1Pt00; At the Furlo Pass it occurs in the Fu1 lumachella, a) lateral view; datable to the Early Pliensbachian (Catriceras Zone). b) whorl section; natural size (drawing by F. Venturi). 88 Bollettino della Società Paleontologica Italiana, 44 (2), 2005

Material - Three middle-large sized specimens leaf; at least seven umbilical lobes were counted, among (including one fragment), and one middle-small which the outermost (U2) is slightly more long than 2/ exemplar, all with visible suture. 3 of L. Remarks and comparisons - Chiefly basing on ornamentation and flattening, we deem that our Stratigraphic distribution - The specimens come specimens can be compared with the description of P. from the Fu1 lumachella, datable to the Early retroplicatum present in the literature. At first, the ribs Pliensbachian (Catriceras Zone). According to Fantini are proverse and describe a forward-concave curve, Sestini (1971), the species P. retroplicatum was found then they project backward, forming a convex arc; in the Pliensbachian of the Austria and in the Domerian about midway on the flank, they become radial, and at (late Pliensbachian) of the France. last they cross the ventral area. This is consistent with the rib pattern reported by Fantini Sestini (1971): «pieghe presenti solo sulla metà esterna dei fianchi e Family JURAPHYLLITIDAE Arkell, 1950 sul ventre, dapprima debolmente concave adoralmente, poi decisamente convesse (folds are present only on Genus Juraphyllites Müller, 1939 the outer half of the flanks and on the venter; at first they are weakly concave adorally, then they are decidedly Type species - Phylloceras diopsis Gemmellaro, convex)». The shell shape is moderately flattened, 1884. contrary to what can be seen in other species, as for instance P. tenuistriatum (Meneghini). Juraphyllites libertus (Gemmellaro, 1884) The suture of our forms shows all the features of Pl. 1, figs. 4a-b; Pl. 2, fig. 1 the genus, having E more than one half and a little less than 2/3 long as L (this length difference grows with 1884 Phylloceras libertum GEMMELLARO, p. 4, pl. 2, figs. 1-5. the ontogenetic development); diphyllic ES saddle; 1899 Rhacophyllites libertus (Gemmellaro) - FUCINI, p. 152, pl. triphyllic LS1 saddle with not much backward inner 20, fig. 1.

EXPLANATION OF PLATE 1

Various ammonoids coming from the Fu1 lumachella (Furlo Pass). Unless contrary indications, all specimens are at natural size. Phragmocone and body chamber cannot be distinguished. Fig. 1 - Phylloceras meneghinii Gemmellaro. Lateral (a) and ventral (b) views of Fu1Ph11. Figs. 2-3 - Lytoceras fimbriatoides Gemmellaro. 2 - Lateral view (a) and whorl section (b) of Fu1Ly01. 3 - Lateral view of Fu1Ly02. Fig. 4 - Juraphyllites libertus (Gemmellaro). Lateral (a) and ventral (b) views of Fu1J10. Figs. 5, 11-12 - Omoderoceras latispira nov. sp. 5 - Ventral (a) and lateral (b) views of Fu1E03. 11 - Lateral (a) and ventral (b) views of holotype, Fu1E01. 12 - Lateral view (a) and whorl section (b) of paratype, Fu1E04. Fig. 6 - Galaticeras canavarii (Fucini). Lateral (a) and ventral (b) views of Fu1G41. Figs. 7-8, 10 - Radstockiceras fastigatum nov. sp. 7 - Lateral view (a) and whorl section (b) of holotype, Fu1R08. 8 - Lateral (a) and ventral (b) views of Fu1R18. 10 - Lateral (a) and ventral (b) views of paratype, Fu1R12. Fig. 9 - Caleites calensis (Faraoni, Marini, Pallini & Venturi). Lateral view (a) and whorl section (b) of Fu1P03. Fig. 13 - Indeterminate new genus. Lateral (a) and ventral (b) views of Fu1X01. Figs. 14-16 - Catriceras cf. campiliense (Fucini). 14 - Lateral (a) and ventral (b) views of Fu1T13. 15 - Lateral view (a) and whorl section (b) of Fu1T14. 16 - Lateral view (a) and whorl section (b) of Fu1T12. Figs. 17-19 - Pelingoceras pseudocarinatum nov. gen et nov. sp. 17 - Ventral (a) and lateral (b) views of holotype, Fu1Pe01. 18 - Lateral (a) and ventral (b) views view of paratype, Fu1Pe04. 19 - Ventral view of paratype, Fu1Pe04; magnified x 3. Fig. 20 - Apoderoceras sp. Lateral view of Fu1E13; reduced x 0.8 . F. Venturi, C. Nannarone, M. Bilotta - Liassic ammonite faunas from the Apennines Pl.89 1 90 Bollettino della Società Paleontologica Italiana, 44 (2), 2005

1901 Rhacophyllites libertus (Gemmellaro) - FUCINI, p. 71, pl. pl. 8, fig. 7) as Rhacophyllites transylvanicus Hauer 12, figs. 5, 8. Var. dorsocurvata, but this latter [listed as as a synonym 1977 Juraphyllites libertus (Gemmellaro) - WIEDENMAYER, p. 35- of J. nardii (Meneghini) by Blau (1998) and Meister et 36, fig. 8; pl. 1, fig. 4; pl. 3, figs. 1-2, 5. al. (2002)] has less flexuose ribs and much weaker 1996 Juraphyllites libertus (Gemmellaro) - FARAONI, MARINI, PALLINI & VENTURI, p. 81, pl. 1, fig. 7. ventral chevron.

Material - Twelve various-sized specimens Stratigraphic distribution - At the Furlo Pass this (including fragments), coming from the Fu1 lumachella, form seems currently known only in the Fu1 lumachella, and one middle-sized exemplar, coming from a Fu2 datable to the Early Pliensbachian (Catriceras Zone). lumachella erratic block. Order PSILOCERATIDA Houša, 1965 Measurements - Number d u h w u/d w/h h/d w/d Remarks - The name (and sometimes also the rank) Fu1J09 25.4 7.0 10.2 7.6 0.28 0.75 0.40 0.30 of the taxon comprising the forms traditionally placed Fu1J12 19.0 5.8 8.0 6.5 0.31 0.81 0.42 0.34 by most Authors in suborders Lytoceratina and Fu1J01 17.3 5.3 7.2 4.8 0.31 0.67 0.42 0.28 Ammonitina is still a matter of different opinions. Fu1J14 17.0 5.2 7.0 5.5 0.31 0.79 0.41 0.32 Fu1J15 13.2 4.2 5.8 4.9 0.32 0.84 0.44 0.37 Wiedmann (1970), Wiedenmayer (1979) and Fu2J01 16.2 5.8 6.0 4.7 0.36 0.78 0.37 0.29 Wiedmann & Kullmann (1981) designated it as order Lytoceratida, but this may be confused with the Remarks - Generally speaking, the precise distinction homonymous taxon used for example by Houša (1965) of the various species referred to Juraphyllites can be and Besnosov & Michailova (1983, 1991) to include sometimes quite hard, because it is chiefly based on “lytoceratines” alone. the presence or absence of constrictions and on the Guex (1987) proposed for this group the rank of ribs features: therefore the judgement can be largely suborder, and the name Psiloceratina: maintaining the influenced by the preservation of the material and by spirit of this taxonomic framework, Dommergues the lack of body chamber fragments. In our case, (2002), indicates the classic “Lytoceratina” and however, the specific attribution did not presented “Ammonitina” taken together as order Psiloceratida. particular problems, since the aspect of the only body Although this denomination can produce some chamber fragment fits with that of the Juraphyllites misunderstandings too (since Psiloceratida were libertus holotype. A remarkable similarity exists also established by Houša, 1965 to unite superfamilies with other specimens assigned to this taxon, such as Psiloceratoidea and Eoderoceratoidea), we believe that for instance those figured by Cope (1991, pl. 2, figs. this is a preferable choice, hence we adopt it in the 5, 13) or by Alkaya & Meister (1995, pl. 3, figs. 1, 5, present paper. 7). Within the Psiloceratida, it is very difficult to identify The individuals constituted by phragmocone alone well-supported groups with intermediate rank between but clearly provided of constrictions are referred without order and family for the forms traditionally ascribed to too much doubts to the species J. libertus as well, since the “lytoceratines”. Though Dommergues (2002) the constrictions seem to be one of the characters referred them all to a single superfamily Lytoceratoidea, which enables a better differentiation from other taxa we do not feel up to entirely share this opinion, because of the same genus. we deem that the relationships among the various groups are still insufficiently understood. In this we Stratigraphic distribution - The species has agree with Rakús (1999), who observed that the apparently a quite wide range, being known from the knowledge of the first Early Jurassic representatives late Sinemurian (as reported also by Blau, 1998) to the of the “lytoceratines” is still incomplete and rather full early Toarcian. At the Furlo Pass it was found in the of gaps, which is reflected on the scarcity of Fu1 and Fu2 lumachellas, both datable to the Early information about the phyletic relations and the Pliensbachian (Catriceras Zone). systematics within the group. Concerning this subject, data are poor and sometimes uneasy to appraise (especially for the Hettangian and early Sinemurian), Juraphyllites sp. but, as already noted by Luppov & Druschits (1958), it might seem that the affinities between the Material - Three body chamber fragments. Lytoceratidae and some of the remaining “lytoceratines” (for instance the Ectocentritidae) are not very close. Remarks and comparisons - The body chamber is To deepen this hypothesis it would be necessary to ornated by close and flexuose ribs, developed only on investigate mainly the development and evolution of the outermost two-thirds of the flank, but “erased” the inner lobe of the suture line (with particular reference towards the umbilicus, and forming a marked ventral to the presence of cruciform aspect and septal chevron. Constrictions are absent or anyway very poorly terminations). Failing convincing proposals, and waiting engraved. for adequate studies, we thought it best to omit any The ornamentation style is summarily comparable indication at suborder, and for “lytoceratines” also with that of the specimen designated by Fucini (1901, superfamily, level. F. Venturi, C. Nannarone, M. Bilotta - Liassic ammonite faunas from the Apennines 91

Family LYTOCERATIDAE Neumayr, 1815

Genus Lytoceras Suess, 1856

Type species - Ammonites fimbriatus J. Sowerby, 1817.

Lytoceras fimbriatoides Gemmellaro, 1884 Figs. 6a-b; Pl. 1, figs. 2a-b, 3

1884 Lytoceras fimbriatoides GEMMELLARO, pl. 3, figs. 20-23.

Lectotype - The two specimens figured by Gemmellaro (1884, pl. 3, figs. 20-23) are here Fig. 6 - Suture lines of Lytoceras fimbriatoides Gemmellaro; designated respectively as lectotype and paralectotype. note the typical “lytoceratine” structure, with E shorter than L (which is bifid) and the well-developed U2; Material - Two small-sized specimens, with partially a) specimen Fu1Ly02, drawn at a diameter of about 18 mm; preserved test. b) specimen Fu1Ly01, drawn at a diameter of about 11 mm (drawings by F. Venturi). Measurements - Number d u h w u/d w/h h/d w/d Fu1Ly01 24.5 7.3 9.5 8.1 0.30 0.85 0.39 0.33 Relatively simplified suture, with E nearly as long Remarks - Our specimens are very similar to those as L, which is trifid; LS1 saddle much more advanced figured by Gemmellaro (1884) both for the very rapid than ES (at least since a diameter of 6 mm); well height increase of their whorl, and for the aspect of developed U2; not markedly subdivided U1 lobe, with the striae on the shell. small U1v; narrow I lobe, not cross-shaped and without The inner whorls are quite well-preserved, and they particularly evident lateral branches. At times, I lobe appear smooth. The suture is only partially visible, but can show feeble septal terminations (i.e. its lower its characters are fairly clear. branches embrace the foregoing I lobe); otherwise, it does not embrace the previous lobe, but is lean on it, Stratigraphic distribution - At the Furlo Pass the with a small spacing between the end of a lobe and the specimens were found in the Fu1 lumachella, datable beginning of the subsequent one (Fig. 7). to the Early Pliensbachian (Catriceras Zone), but one exemplar closely comparable to this species occurs also Remarks - The present family is proposed to include at the Pallareto Quarry (“Venturi ’78” bed, referred to Holcolytoceras Spath and Aegolytoceras Spath. As a the base of the Pliensbachian). rule, these genera are placed in two distinct groups: Dommergues et al. (2000) quote the species in the former is usually referred to Ectocentritidae (e.g. association with taxa indicating the lower and/or middle Arkell et al., 1957; Page, 1993; Dommergues et al., part of the Early Pliensbachian. 2000), whereas the latter is traditionally related to The forms called L. aff. fimbriatoides by Derolytoceras Rosenberg in the family Derolytoceratidae Dommergues et al. (1994) are reported at the top of (e.g. Arkell et al., 1957; Fantini Sestini, 1973; Venturi, the Echioceras raricostatum Zone (uppermost 1985; Cope, 1991; Meister et al., 2002). A sufficiently Sinemurian), but they seem to persist in the lower part close relationship between Holcolytoceras and of the Early Pliensbachian. Aegolytoceras was suggested by Venturi & Ferri (2001), who put them (together with Tragolytoceras Spath) in a separate Derolytoceratidae subfamily, the Family HOLCOLYTOCERATIDAE nov. fam. Holcolytoceratinae. Our new data induce us now to further improve this opinion, for the following reasons: Type genus - Holcolytoceras Spath, 1924. 1) Holcolytoceras and Aegolytoceras share several traits as per coiling, whorl section, ornamentation and Diagnosis - Platycone shells, always rather evolute; suture line, which on the contrary are completely lacking whorl with poor overlapping, but slightly more than in in Derolytoceras: their affinity with this latter genus typical Lytoceratidae. does not seem to be particularly close, thus we do not The whorl section is at first rounded, then it becomes deem proper to include them all in the same family; subrectangular, quadrate-elliptic or ellipsoid-suboval. 2) currently the existence of a family In almost all occasions the phragmocone is smooth; Derolytoceratidae is disowned by many internal moulds show evident constrictions followed ammonitologists: Derolytoceras in fact, is often by varices; the body chamber ornamentation is chiefly considered a subgenus or even the microconch form ventral, and it is formed by crossing ribs (more or less of Lytoceras (as reported among others by Guex, 1972 faint) which start from the ventro-lateral edge, and El Hariri et al, 1996), and one cannot deny that, at longitudinal striae and often also small spines. a small diameter, the sutures of Derolytoceras and 92 Bollettino della Società Paleontologica Italiana, 44 (2), 2005

Lytoceras are extremely similar (as clearly shown by 3) in Audaxlytoceras the ventral area can be Wiedmann, 1970, fig. 8; Dommergues, 2002, figs. 6 flattened; in Aegolytoceras it is always rounded; e-l); in any case, several Authors classify Derolytoceras 4) in Audaxlytoceras constrictions are weakly in the family Lytoceratidae (e.g. Schlegelmilch, 1992; convex on the flank of the whorl, drawing a simple Lachkar et al., 1998; Hillebrandt, 2002, Dommergues, radial curve; in Aegolytoceras constrictions form a 2002), and now this position is preferable also for us; forward inflexion at about the middle of the flank, and 3) Tragolytoceras seems to have closer relations with their varices are morphologically different; Analytoceras Hyatt than with the group of 5) Audaxlytoceras characterizes a time interval Holcolytoceras and Aegolytoceras: this is suggested by ranging from the upper portion of the Early the transitional characters of the Apennine species Pliensbachian to part of the upper Toarcian; Analytoceras canavarii Venturi & Nannarone, which Aegolytoceras is known with some doubt in the upper has parabolic nodes and articulated inner stage typical Sinemurian and with certainty in the lower part of the for Analytoceras, but adult ornamentation similar to Early Pliensbachian (as a matter of fact, one can say some Tragolytoceras [as for instance the T. adneticum that Audaxlytoceras succeeded to Aegolytoceras, (Hauer) figured in Venturi & Ferri (2001, p. 81)]; perhaps replacing it in the same ecological niche). 4) we think that the features which allow to We therefore believe that the specimens attributed recognize a relationship between Holcolytoceras and by Fucini (1901) to Lytoceras serorugatum and Aegolytoceras (coiling, ornamentation and sutural designated by Fantini Sestini (1973) with the new name morphology) cannot be strictly assimilated to those of Audaxlytoceras fucinii are to be assigned to the genus the other Liassic “lytoceratine” taxa. Aegolytoceras (for which they constitute the type Basing on these reasons, we think it convenient to species). With regard to the forms of Geyer (1886) we recognize for Holcolytoceras and Aegolytoceras alone cannot exclude that they really belong to a separate suprageneric taxon (here ranked as family), Audaxlytoceras, but the lack of suture line does not which significance is more restricted and even better allow to assert it with reasonable certainty. defined than that attributed to the Holcolytoceratinae in Venturi & Ferri (2001). Aegolytoceras varicosum (Venturi, 1978) Fig. 7 Genus Aegolytoceras Spath, 1924 1978(?) Audaxlytoceras varicosum VENTURI, p. 107, figs. 4, 12b; Type species - Audaxlytoceras fucinii Fantini Sestini, pl. 1, figs. 6-7. 1973 (Lytoceras serorugatum Fucini, 1901, non Stur in 1991 Aegolytoceras cf. serorugatum (Geyer) - COPE, pl. 1, figs. Geyer, 1886). 5, 7-8. Material - Four small-sized specimens and one Remarks - Arkell et al. (1957) believe that the middle-sized fragment. generotype is Lytoceras serorugatum Geyer, 1886, but they figure the specimen wrongly attributed to this Measurements - species by Fucini (1901, p. 76; fig. 36; pl. 12, fig. 9), Numberduhwu/dw/hh/dw/d for which the subgenus Geyeria was originally Fu2A03 15.0 6.6 4.0 3.8 0.44 0.95 0.27 0.25 proposed. Afterwards, this individual (with its mistaken 6.6 2.9 1.9 1.8 0.44 0.95 0.29 0.27 generic denomination) was chosen by Spath (1924) as Fu2A04 12.1 5.4 3.9 0.45 0.32 the type of Aegolytoceras, instituted to replace the Fu2A05 9.9 4.5 3.1 2.8 0.45 0.90 0.31 0.28 preoccupied name Geyeria. Fantini Sestini (1973) observes that between the specimens indicated by Geyer (1886; p. 229, pl. 2, figs. 7-9) as Lytoceras nov. sp. indet. (Lyt. serorugatum Stur m.s.) and those attributed by Fucini (1901) to L. serorugatum some differences do exist (chiefly concerning the aspect of the ventral area): this lead the Author to classify them as two separate species, both attributed to Audaxlytoceras Fucini (for which Aegolytoceras was considered a synonym). In our opinion, however, as already shown by Venturi & Ferri (2001), Aegolytoceras is clearly distinct from Audaxlytoceras and cannot be considered as its synonym, for the following reasons: 1) in Audaxlytoceras E is markedly shorter than L, which is bifid (with an outer branch very shifted Fig. 7 - Inner portion of the suture line of an Aegolytoceras towards E) and has a narrow trunk; in Aegolytoceras varicosum (Venturi), drawn from a specimen found in the Pallareto Quarry section; magnified about x 4; note that I lobes the length difference between E and L is not so do not embrace, but are nearly leaning one against each other, accentuated, L is trifid and has a broad trunk; and do not show the two most typical characters of true 2) in Audaxlytoceras LS1 and ES saddles are aligned, lytoceratids (septal terminations and marked lateral branches); so they do not show differences in their advancement; basing also on this reason, here we propose for Aegolytoceras in Aegolytoceras the LS1 saddle is much more advanced and Holcolytoceras the new family Holcolytoceratidae (drawing than ES; by F. Venturi). F. Venturi, C. Nannarone, M. Bilotta - Liassic ammonite faunas from the Apennines 93

Remarks - The three specimens reported by Cope ? Family ECTOCENTRITIDAE Spath, 1927 (1991, pl. 1, figs. 5, 7-8) as Aegolytoceras cf. Subfamily PELTOLYTOCERATINAE Venturi & Bilotta, serorugatum seem to us more similar to our species 2001 than to the Geyer (1886) one, and indeed the Author probably meant to refer his material to Lytoceras Remarks - This group was recently proposed serorugatum Fucini, 1901 (i.e. the type species of (Venturi & Bilotta, 2001) to formally ratify the close Aegolytoceras). relationship recognized among the genera Exomiloceras Wiedenmayer, Peltolytoceras Spath and Galaticeras Stratigraphic distribution - Our material lacks Spath. Its placing as an Ectocentritidae subfamily was precise stratigraphic reference, as it comes from an originally justified by the fact that the nominal genus erratic block which get detached from the Grilli Quarry (Peltolytoceras) is usually referred to the same family face where the lumachella Fu2 outcrops. At the as Ectocentrites Canavari (e.g. Arkell et al., 1957; neighbouring Mount Acuto this species occurs in Luppov & Druschits, 1958) for the common presence “Venturi ’78” bed, dated to the beginning of the Early of a similar trifid L lobe and/or basing on the Pliensbachian (base of the Catriceras Zone). ornamentation. However, in some cases (for instance Roman, 1938; Rakús, 1999) this classification seems above all due to the very wide meaning of the Aegolytoceras cf. varicosum (Venturi, 1978) suprageneric taxon in which Peltolytoceras and Figs. 8a-b Ectocentrites are placed. Moreover, some Authors do not believe that these Material - Seven middle-small sized specimens, two genera belong to the same group: chiefly basing including one fragment. on the characters of the external suture, Wiedmann (1970) ascribes Ectocentrites and Peltolytoceras to Measurements - separate families, respectively Pleuroacanthitidae and Number d u h w u/d w/h h/d w/d Analytoceratidae. Wiedenmayer (1979, 1980) included Fu1A07 18.2 7.2 5.8 5.4 0.40 0.93 0.32 0.30 Exomiloceras just to the latter taxon, and this scheme Fu1A08 13.2 4.9 4.5 4.2 0.37 0.93 0.34 0.32 was followed by Venturi (1978, 1985), who considered Fu1A09 11.3 4.7 4.2 4.0 0.42 0.95 0.37 0.35 Exomiloceras and Galaticeras as Analytoceratidae. Description - Evolute shell, with whorl height Indeed, the presence of an I lobe with septal (i.e. increasing from 2 to 2.5 times per whorl. embracing) terminations seem to indicate Analytoceras The ornamentation is formed by ventral ribs on the (and not Ectocentrites) as the closest form for the body chamber, already visible from a diameter of about Exomiloceras, Peltolytoceras and Galaticeras group. 10 mm, and by constrictions with a broad and deep We do not know if Exomiloceras and Peltolytoceras umbilical portion, which are backward bended on the too have inner lobe with septal branches, but anyway flank and radially cross the ventral area. we must note that this feature is not completely unambiguous, since its presence or absence could not Remarks and comparisons - At a parity of diameter, be decisive to determine the membership of the family. this form differs from Aegolytoceras varicosum Even though we confirm the opinion that (Venturi, 1978) for its greater whorl height increase, Exomiloceras, Peltolytoceras and Galaticeras do show its greater ventral area width, and for the earlier mutual close affinity, we must admit that their appearance of the radial ribs. relationships with other taxa are not sufficiently clear. For these reasons, we now think it convenient to express Stratigraphic distribution - At the Furlo Pass this some doubt on the attribution of the Peltolytoceratinae form occurs in the Fu1 lumachella, datable to the Early to the family Ectocentritidae. Pliensbachian (Catriceras Zone). Genus Galaticeras Spath, 1938

Type species - Amphiceras harpoceroides Gemmellaro, 1884.

Remarks - The diagnosis of this genus was recently revised by Venturi & Bilotta (2001) and Venturi & Ferri (2001), but also by Rakús & Guex (2002). The latter Authors support the idea (already advanced for example by Dubar, 1961; Blau, 1998; Rakús, 1999) that Galaticeras and Bouhamidoceras Dubar belong to the same subfamily, for the following reasons: 1) asymmetric suture line, with cross-shaped inner lobe (IS) [actually, this notation properly indicates only Fig. 8 - Aegolytoceras cf. varicosum (Venturi), fragment Fu1A00; the presence of septal terminations, not that of lateral a) whorl section; branches, but Rakús & Guex (2002) seem to use it b) lateral view; about natural size (drawings by F. Venturi). quite indifferently in both meanings]; 94 Bollettino della Società Paleontologica Italiana, 44 (2), 2005

2) presence of longitudinal depressions in peri- Galaticeras (Blau, 1998); in some cases the presumed ventral position (ventral “slimming”); existence of this taxon in the late Sinemurian is merely 3) presence of poorly-marked constrictions. a not verifiable quotation, lacking support of figures We must observe that these characters do not seem and reference to stratigraphic sections. to us reliable signs for such a close relation between According to the Apennine data, as already stated the two genera, also because they are not regularly in Venturi & Bilotta (2001), the chronostratigraphic distributed even among the various Galaticeras species. range of Galaticeras includes the Pliensbachian alone More in particular, we deem that one can raise the (from the Catriceras Zone to the Metaderoceras following objections: gemmellaroi Zone). As far as we know, no species 1) the suture of Bouhamidoceras has a bifid L lobe, correctly ascribable to this genus was found associated whereas in Galaticeras it is clearly trifid (Venturi & in a bed with typical late Sinemurian taxa. Bilotta, 2001; Venturi & Nannarone, 2002); the asymmetric position of E is not shared only by these two genera, but it is also present in many not closely Galaticeras canavarii (Fucini, 1899) related Liassic taxa (Venturi & Bilotta, 2001); the cross- Figs. 9-11; Pl. 1, figs. 6a-b; Pl. 2, figs. 5-10 shaped and/or septal terminations-bearing inner lobe is a common character for several “lytoceratines”, and 1899 Amphiceras? Canavarii FUCINI, p. 167 (23), pl. 23 (5), sometimes it is differently accentuated even among the fig. 1. species of the same genus [for example Galaticeras catriense (Venturi) has the two lateral branches of I Lectotype - The only specimen figured by Fucini unevenly developed, while in G. canavarii (Fucini) these (1899, pl. 23, fig. 1) is here formally designated as are more regular]; lectotype. 2) among Galaticeras, the ventral “slimming” is present only in the type species (G. harpoceroide) and, Material - Fifty-two various-sized specimens to a lesser extent, in the other Gemmellaro’s (1884) (including several fragments), coming from the Fu1 Sicilian forms characterizing the Miltoceras sellae Zone lumachella, and fifty-three mostly middle-small sized (Faraoni et al., 1996); this feature is absent in the two specimens, coming from a Fu2 lumachella erratic Catriceras Zone species (G. catriense and G. block. canavarii), which are nevertheless attributed to Galaticeras with good confidence; Measurements - 3) constrictions are apparently lacking in G. Numberduhwu/dw/hh/dw/d Fu1G01 85.2 32.3 31.2 ~25.2 0.38 ~0.81 0.37 ~0.30 harpoceroide, whereas they can be considered a typical Fu1G15 59.0 21.8 23.0 15.8 0.37 0.69 0.39 0.27 character of the Catriceras Zone species: in G catriense, Fu1G22 40.8 13.8 16.5 11.8 0.34 0.72 0.40 0.29 though not very deep, they generally involve only the Fu1G24 39.4 11.8 15.3 11.5 0.30 0.75 0.39 0.29 phragmocone, while in G. canavarii they are at times Fu1G42 25.7 7.2 10.5 7.6 0.28 0.72 0.41 0.30 very marked also on the body chamber (however, the Fu1G48 17.0 5.8 6.2 5.5 0.34 0.89 0.36 0.32 presence of a pseudo-test tends to efface them). Fu1G49 14.5 4.9 6.5 5.0 0.34 0.77 0.45 0.34 Fu1G50 12.3 4.0 5.2 4.2 0.33 0.81 0.42 0.34 The ontogeny of Galaticeras, so well illustrated by Fu2G01 21.2 16.9 8.9 6.1 0.80 0.69 0.42 0.29 Rakús & Guex (2002), is another element that do not Fu2G06 14.7 5.0 5.5 4.3 0.34 0.78 0.37 0.29 support the placing of this genus in the subfamily Fu2G16 13.9 3.9 5.2 4.2 0.28 0.81 0.37 0.30 Bouhamidoceratinae (Figs. 11d1-d4): in fact it does not Fu2G12 12.1 4.2 4.9 4.0 0.35 0.82 0.40 0.33 show a development like that of Bouhamidoceras, which Fu2G28 11.8 3.6 4.5 3.5 0.31 0.78 0.38 0.30 instead undergo a very peculiar whorl section and 4.0 1.5 2.2 2.0 0.38 0.91 0.55 0.50 coiling change during its growth. Finally, we note that Fu2G23 11.5 3.9 4.5 3.9 0.34 0.87 0.39 0.34 Fu2G34 10.9 3.2 4.5 3.2 0.29 0.71 0.41 0.29 the definition of the Bouhamidoceratinae given by Rakús Fu2G37 9.5 3.1 4.0 3.1 0.33 0.78 0.42 0.33 (1999) seems to us almost totally incompatible with Fu2G46 9.2 3.0 3.9 3.0 0.33 0.77 0.42 0.33 the characters observable in Galaticeras, fitting very Fu2G47 9.0 2.8 3.8 2.9 0.31 0.76 0.42 0.32 well to the nominal genus alone. Therefore, we deem Fu2G53 7.4 2.1 3.0 2.5 0.28 0.83 0.41 0.34 Bouhamidoceras as the representative of a valid Fu2G52 7.1 2.3 3.0 2.5 0.32 0.83 0.42 0.35 suprageneric taxon, which until now it is to be considered as monotypic, since in our opinion its affinity Remarks - The specimen of Fucini (1899) is very with Galaticeras is to be excluded at least at the family small and moderately flattened; it is ornated by ribs level. due to the raising of bundled striae (more evident when the test is preserved), alternated to moderately deep Stratigraphic distribution - Even though the constrictions (about 5 per each whorl), which are more appearance of Galaticeras is sometimes reported (or marked on the ventral area. anyway supposed) in the late Sinemurian (e.g. In our material we observed that the constrictions Wiedenmayer, 1980; Hillebrandt, 1987; Dommergues start only after a diameter of about 5-6 mm, involve et al., 1994; Blau, 1998; Lachkar et al., 1998), we do the whole phragmocone and thicken (up to 5-6 per not know convincing evidences of this. These supposed half whorl) on the ventral area of the body chamber late Sinemurian forms are constantly collected ex situ (Fig. 11). In some small individuals constrictions are (Blau, 1998), or in muddled stratigraphic frameworks very marked and sometimes rather close already by (Dommergues et al., 1994) or wrongly attributed to their first appearance: although these character are not F. Venturi, C. Nannarone, M. Bilotta - Liassic ammonite faunas from the Apennines 95

lectotype, whereas almost all the Fu1 specimens have less deep constrictions, and, at a parity of diameter, they are a little less flattened. However, we deem that these differences are not sufficient to decree a true separation between the two specimen sets: therefore all our material is attributed to the species of Fucini (1899) without reservation. Recently it was proposed (Rakús & Guex, 2002) to assign this species to the genus Castanyiceras Rakús & Guex, which was suggested to be a microconch Fig. 9 - Suture line of Galaticeras canavarii (Fucini), drawn form, probably of Galaticeras itself. Generally speaking, from a fragment of the Fu1 fauna (Fu1G42), at an estimated we have no objection on the validity of Castanyiceras, diameter of about 50 mm; magnified about x 4; note the but we do not believe proper its use for the species “lytoceratine” aspect of I lobe (with pronounced lateral branches, called by Fucini (1899) Amphiceras? Canavarii, which and apparently also septal terminations) and the subdivided U1 characteristics fit better to the diagnosis of Galaticeras. typical for this genus (drawing by F. Venturi). In fact, the type species of Castanyiceras (C. parvulum Rakús & Guex) is relatively broad, and its peristome has an horizontal rostrum and two small lateral “ears” (“jugal apophyses”); on the contrary, G. canavarii is present on the Fucini (1899) type, they are probably narrower, and its peristome shows a nearly vertical juvenile traits, thus they could fall in the normal salience (lappet-like), apparently lacking “jugal intraspecific variability. The large-sized forms (with a apophyses” (Figs. 11a-b). The suture of these two diameter of at least 100 mm) have broad and not species is rather similar (also compared to that of the particularly deep constrictions; on internal moulds these young G. aegoceroide presented by Rakús & Guex, are followed by rather raised varices, which are much 2002, fig. 44e), but it is more simplified in C. parvulum, less evident on the test, where striae are present. which moreover has a shorter L lobe than that of G. The suture resembles closely that of G. catriense, canavarii and other Galaticeras (even though in all and has a characteristic A lobe developed within ES cases E is shorter than L). The I lobe of C. parvulum when the E lobe is shifted enough from the middle of was described as cross-shaped and indicated as IS: the ventral area. since on the figure it does not show lateral branches As a rule, the exemplars coming from the Fu2 (which, instead, are present in G. canavarii), the lumachella have an aspect (including size and Authors were likely referring only to the presence of ornamentation) which is strictly comparable to the septal terminations. We deem that these characters are

Fig. 11 - Galaticeras canavarii (Fucini); a-b) whorl section and lateral view of the peristome drawn from the fragment Fu2G08; note the forward-turned vertical salience (lappet-like) on the venter; magnified about x 3; c) suture line drawn from the exemplar Fu2G13, at a diameter of about 10 mm; as can be seen, the position of E lobe is asymmetrical, and the two ES saddles (between E and L lobes) are different-sized; magnified about x 4; d1-d4) ontogenetic development, drawn from various specimens (d1 and d2: from the same partially crushed fragment Fu2G01; Fig. 10 - Galaticeras canavarii (Fucini), fragment Fu1G01; d3: specimen Fu2G13; d4: specimen Fu2G03), all magnified a) whorl section; about x 1.5; the nucleus is moderately evolute and smooth from b) lateral view; about natural size; constrictions are in part effaced a diameter of 5-7 mm; constrictions first appear from a diameter by the re-crystallized and greatly thickened test layer (drawings of about 8 mm; the whorl is always higher than wide, but the by F. Venturi). flattening increases with the growth (drawings by F. Venturi). 96 Bollettino della Società Paleontologica Italiana, 44 (2), 2005 sufficient to keep C. parvulum and G. canavarii in two only to the inner whorls (between the initial smooth separated, although undoubtedly close, genera: in fact, stage and the ribbed bispinate middle one), or longer one cannot deny a strong resemblance among the and involving outer and middle whorls (in this case a various known forms of Galaticeras and the bispinate ornamentation is never developed). The Castanyiceras figured by Rakús & Guex (2002, pl. 24, transition from middle to outer whorls, when it occurs figs. 4, 7-8). Furthermore, in our collection there are the spoliation (i.e. the weakening and loss of the four or five middle-sized fragments, surely referable ornamentation), takes place always quite precociously. to Galaticeras, with whorl width definitely greater than The ventral area, especially in the inner and middle G. canavarii, and apparently less developed umbilical whorls, is crossed by secondary ribs; at times, on the suture: perhaps they might represent a species flank there may be also small intercalated lateral ribs. morphologically alike to the hypothetical macroconch The suture is indented, and possesses the characters form of Castanyiceras. of the subfamily: E lobe shorter than L (in small specimens this feature is not much evident), with sub- Stratigraphic distribution - The material of the Furlo parallel main branches; large and arborescent L, Pass comes from the Fu1 lumachella and from an erratic essentially bifid, with outer branch tending to invade block which get detached from the Grilli Quarry face the ventral area; suspensive U2 and U3 lobes, inclined where the lumachella Fu2 outcrops. Both assemblages in comparison to L; U2 more or less closed on the are datable to the Early Pliensbachian (Catriceras Zone). bottom by U3 (as a rule more inclined than U2) and by the dorsal branch of L; ES saddle slightly broader than LS1. Superfamily EODEROCERATOIDEA Spath, 1927 Family EODEROCERATIDAE Spath, 1927 Remarks - As in part already suggested for Subfamily PARAMICRODEROCERATINAE Venturi, Omoderoceras cf. latinodosum in Venturi et al. (2004), Nannarone & Bilotta, 2004 some specimens ascribable to this genus occur in Turkey: these are the ammonites erroneously classified Diagnosis - Evolute to involute shell, with whorl as Epideroceras latinodosum Bremer and section variable in shape (sub-rectangular, sub- Gemmellaroceras aegoceroides (Bremer, 1965, p. 161; trapezoidal, sub-quadrate). fig. 3l; pl. 15, fig. 2; p.181; pl. 16, fig. 6), which actually The ornamentation is typical of the superfamily, with do not show the diagnostic features neither of primary ribs normally joining two rows of spines Epideroceras Spath nor of Gemmellaroceras (this is (tubercles on internal mould) and thinner and closer true especially for the second species, which has a secondary ribs, which pass the ventral area without very indented eoderoceratid-like suture). Another form interruption; small intercalated lateral ribs (or striae) which we deem likely comparable to Omoderoceras is are often present too. the middle-sized, flattened and evolute exemplar Discriminant for this subfamily is the suture, wrongly identified by Bremer (1965, p. 182, fig. 4f; pl. indented and with arborescent lobes: E as a rule quite 16, fig. 8) as Gemmellaroceras cortesei (Gemmellaro). narrow, as long as L or shorter (but never longer), with deep median saddle and sub-parallel or slightly Omoderoceras latispira nov. sp. diverging main branches; L with a narrow, more or Pl. 1, figs. 5, 11-12 less long trunk, possessing bifid aspect or, as a form derived from this, trifid, with external branch having Name derivation - From the Latin latus (= broad) the more or less accentuated tendency to invade the and spira (= whorl), with reference to the very broad ventral area; inclined umbilical lobes, sometimes with whorl, both in the inner and outer part of the coiling. U3 nearly perpendicular to L; broad ES and LS1 saddles, with ES oblique toward the external side. Holotype - Fu1E01, middle-sized specimen, All the taxa of this group are exclusively known in apparently without body chamber (Pl. 1, fig. 11), housed the late Sinemurian-early Pliensbachian of the Tethys. in the Earth Sciences Department, Università degli Studi di Perugia.

Genus Omoderoceras Venturi, Nannarone & Bilotta, Paratype - Fu1E04, small-sized specimen, 2004 apparently without body chamber (Pl. 1, fig. 15), housed in the Earth Sciences Department, Università degli Studi Type species - Omoderoceras cantianense Venturi, di Perugia. Nannarone & Bilotta, 2004. Type locality - Furlo Pass (Umbria-Marche Diagnosis - Inner whorls moderately involute, with Apennines). quite broad ribs, almost rectiradiate, ending in a single row of spines; middle whorls (sometimes bispinate) Type section - Grilli Quarry (Furlo Pass), Fu1 and outer ones becoming higher, elliptic and lumachella. compressed, and tending to loose at first the spines, then to undergo a weakening of the ribs. Material - Twelve specimens coming from the Fu1 Characteristic is the presence of a ribbed lumachella and five specimens coming from a Fu2 monospinate phase, that can be rather short and limited lumachella erratic block. F. Venturi, C. Nannarone, M. Bilotta - Liassic ammonite faunas from the Apennines 97

Measurements - occasion it was also advanced the idea that this species Number d u h w u/d w/h h/d w/d might represent the inner whorls of the so-called Pa78ip3 15.4 5.3 5.1 9.0 0.34 1.76 0.33 0.58 Apennine “Tetraspidoceras quadrarmatum”, but this Pa78ip14 8.5 2.5 3.4 4.7 0.29 1.38 0.40 0.55 hypothesis has still to be verified, since we have not Fu1E01 49.2 19.2 19.8 18.7 0.39 0.94 0.40 0.38 Fu1E04 24.1 9.2 8.5 11.7 0.38 1.38 0.35 0.49 found yet large exemplars with preserved inner whorls. Fu1E09 11.5 5.0 3.9 6.6 0.43 1.69 0.34 0.57 Fu1E10 10.0 3.4 3.6 5.2 0.34 1.44 0.36 0.52 Stratigraphic distribution - Early Pliensbachian Fu1E11 9.9 ~3.2 6.5 ~2.03 ~0.32 0.66 (Catriceras Zone). Fu1E12 9.5 2.9 ~3.8 ~5.0 0.31 ~1.32 ~0.40 ~0.53 Fu2E01 15.2 5.8 6.5 8.9 0.38 1.37 0.43 0.59 Fu2E03 12.1 4.1 5.1 6.5 0.34 1.27 0.42 0.54 Genus undetermined Pl. 2, fig. 16 Description of the holotype - Moderately evolute shell, with sub-roundish whorl section, wider than high. 1996 Tetraspidoceras quadrarmatum (Dumortier) - FARAONI, Slightly rounded ventral area, not elevated; moderately MARINI, PALLINI & VENTURI, pl. 2, fig. 1. funnel-shaped umbilicus. The ornamentation is clearly visible only on the outer Material - One fragment of a quite large-sized and middle whorls, where it is represented by specimen. rectiradiate ribs joining two rows of close spines; from the ventro-lateral spines thin and close secondary ribs Remarks and comparisons - The ornamentation originates, crossing the ventral area; on the outer whorls corresponds to that of the specimen erroneously small lateral intercalated ribs (or striae) are present. ascribed by Faraoni et al. (1996) to Tetraspidoceras The suture line is not visible. quadrarmatum: broad and rectiradiate primary ribs, with evident intercalated secondary ribs and two close large Diagnosis - Moderately evolute shell, with whorl spines (in our fragmentary material only the upper one section from wide sub-trapezoidal in the inner whorls is visible, since the lower part of the whorl is broken). to wide sub-roundish in the outer ones; slightly rounded The generic attribution of these forms is still ventral area, not elevated. problematic. The scarcity of well-preserved material, The inner whorls show, from a diameter of about 4 especially in the inner whorls, does not allow to make mm, the ribbed monospinate stage that is characteristic convincing hypotheses, and the possible relations with for the genus, with rectiradiate primary ribs and the already-cited Omoderoceras latispira, as suggested intercostal space narrower than the ribs themselves. in Venturi et al. (2004), remain to be verified. At a diameter of about 8 mm the ornamentation becomes ribbed bispinate: initially the umbilical spines Stratigraphic distribution - At the Furlo Pass this are very small, but afterwards they grow larger, and at form was found in the Fu2 lumachella, datable to the times they are so close to the ventro-lateral ones that Early Pliensbachian (Catriceras Zone). they nearly seem to form a single rib. From a diameter of about 24 mm onwards small lateral ribs (or striae) intercalated between the primary ones are clearly Subfamily COELOCERATINAE Haug, 1910 visible. The ventral area is crossed by thin and close secondary ribs originating from the ventro-lateral spines. Genus Apoderoceras Buckman, 1921 Suture line with E nearly as long as L, which is bifid; due to the remarkable whorl width, the outer Type species - Apoderoceras lobulatum Buckman, branch of L is on the ventral area, but it does not seem 1921. tending to close E on the bottom; ES saddle with two accessory lobes. Apoderoceras sp. Pl. 1, fig. 20 Remarks and comparisons - In this species we do not observed two sutural traits typical for Material - One fragment of a middle-sized Omoderoceras, namely the different length of E and L specimen, with outer cast. lobes and the tendency of the latter to close on the bottom E itself. This is probably due to the small size Measurements - of the exemplars, since in the other species of this genus Number duhwu/dw/hh/dw/d the characters at issue become evident only starting Fu1E13 38.5 17.0 13.6 ~14.0 0.44 ~1.03 0.35 ~0.36 from a certain diameter onwards, and normally they are enhanced during the growth (Venturi et al., 2004). Remarks and comparisons - On the flanks of our Some of the material from the Fu2 lumachella was exemplar the primary ribs with intercalated secondary already reported in Venturi et al. (2004, pl. 2, figs. 5, ribs crossing the ventral area are evident; moreover, 9a-b, 12) as probably belonging to this new the junction of the spines is visible. From what can be Omoderoceras species, and now we think that the two ascertained, the whorl section is probably sub- small individuals from the Pallareto Quarry (“Venturi trapezoidal. ’78” bed) figured in Venturi et al. (2004, pl. 1, fig. 4; Even though the fragmentariness of our specimen text-fig. 7b) can be ascribed to it as well. In the same does not allow exhaustive considerations, its coiling, 98 Bollettino della Società Paleontologica Italiana, 44 (2), 2005 ornamentation and whorl section seem to us clearly The suture line is not very indented, with E as long comparable with those of the inner whorls of as L or more, placed in a very asymmetric position Apoderoceras hamiltoni Simpson [which, according compared to the middle of the ventral area; small U2 to Howarth (2002), is a synonym of A. subtriangulare and U3 lobes; LS1 saddle slightly more advanced than (Young & Bird); see the exemplars figured in Buckman ES. (1924, pl. 530b) and in Howarth (2002, pl. 6, fig. 5)], A. aculeatum (Simpson) [specimen in Howarth (2002, Remarks and comparisons - The material collected pl. 6, figs. 2a-b)] and A. triornatum Buckman [exemplar at the Furlo Pass allowed us to integrate the original in Buckman (1928, pl. 783b)]. diagnosis of the type species (Faraoni et al., 1996) and As previously noted (Venturi et al., 2004), the that of the genus (Venturi & Ferri, 2001), completing appearance in the Apennine of forms ascribable to them. This enables a better comparison between this Apoderoceras does not occur within the first post- taxon and some middle-Liassic small-sized Tethyan Sinemurian fauna (i.e. “Venturi ’78” bed), but in a ammonoids, usually included in Gemmellaroceras Hyatt slightly subsequent assemblage. The “delayed” (for example the species called by Gemmellaro, 1884, occurrence of this genus in our area reduces the pl. 3, fig. 19; pl. 4, figs. 3-6, Aegoceras granuliferum), precision in the use of the main biostratigraphic criterion which may appear similar to Caleites for their adopted to formalize the Sinemurian-Pliensbachian ornamentation, more substantial than that of G. GSSP (which is exactly the first occurrence of aenigmaticum Gemmellaro. In our opinion, the Apoderoceras), and this results in correlation ornamentation resemblance between these difficulties. Gemmellaroceras and Caleites is to be interpreted as a morphological convergence. Even though they share Stratigraphic distribution - The material from the with Caleites the aspect of the first whorls (smooth Furlo Pass was found in the Fu1 lumachella, datable to and involute), as well as some sutural features, the Early Pliensbachian (Catriceras Zone). Comparable Gemmellaroceras can be distinguished without English species are referred to the Phricodoceras taylori ambiguity by the following characters: Subzone. 1) more evolute and less flattened shell in the outer whorls; 2) ornamentation formed by pseudo-ribs (apparently Family POLYMORPHITIDAE Haug, 1887 due to bundling of striae) which do not seem to be well reproduced in the internal moulds; Remarks - In accordance with the opinions reported 3) suture with larger E lobe, placed in an almost by Dommergues & Meister (1999) we think it symmetric position (never strongly asymmetric, or convenient to give this family a more reduced ambit nearly so) and LS1 saddle more advanced than ES; than that traditionally adopted by various Authors 4) younger stratigraphic position (the first specimens (including for instance Arkell et al., 1957, Bremer, 1965, surely ascribable to this genus occur only from the Widenmayer, 1977). middle-upper part of the Miltoceras sellae Zone). The differences between Caleites and other Subfamily POLYMORPHITINAE Haug, 1887 Polymorphitidae, such as Platypleuroceras Hyatt are even greater: the pattern of the ribs (which in Genus Caleites Venturi & Ferri, 2001 macroconchs cross the ventral area forming no chevron), the aspect of the ventral area (tabular or Type species - Polymorphites calensis Faraoni, weakly blunt), the presence of two rows of spines (the Marini, Pallini & Venturi, 1996. outermost one being in marginal position) as well as the symmetry of the suture which can be observed on Emended diagnosis - Platycone shell, middle to the type species (figured for instance in Arkell et al., small-sized, moderately evolute; the coil nearly doubles 1957 and Schlegelmilch, 1992) and in the most closely its height in a whorl, with poor overlapping (about 1/ related forms, would exclude any possible 6). misinterpretation. Sub-quadrate or sub-roundish-rectangular whorl section, higher than wide. Stratigraphic distribution - Early Pliensbachian Rounded ventral area, tendentially raised and (lower-middle part of the Catriceras Zone). smooth, with lateral costal traces. Sub-convex flanks, with rounded umbilical margin Caleites calensis (Faraoni, Marini, Pallini & Venturi, and shallow umbilicus. 1996) Ornamentation formed by radial or slightly proverse Pl. 1, figs. 9a-b sharp ribs, narrower than the intercostal spaces, regularly spaced and rather elevated, originating near ?1975Polymorphites granuliferum (Gemmellaro) - FERRETTI, p. the umbilical margin and becoming stronger on the 178, pl. 24, fig. 3. middle of the flank. On the ventro-lateral edge the ribs 1980 Polymorphites sp. nov. (?) SCHLATTER, p. 94, pl. 7, fig. 7a- end in short spines with roundish section, then become b; Text-fig. 16, E. 1996 Polymorphites calensis FARAONI, MARINI, PALLINI & proverse and fade on the ventral area, forming an VENTURI, p. 96, pl. 3, figs. 13-14, 17-18; pl. 9, figs. 1-3. evanescent but clearly visible angle (chevron). 2001 Caleites calensis (Faraoni, Marini, Pallini & Venturi) - VENTURI & FERRI, p. 137. F. Venturi, C. Nannarone, M. Bilotta - Liassic ammonite faunas from the Apennines 99

Material - Six middle-small sized specimens, a great difference in the aspect of the whole suture on including three fragments. the two flanks: on the side where E lies, the ES saddle is much narrower, and L lobe is shorter than E itself Measurements - (which replaces L in its “usual” position); on the Number d u h w u/d w/h h/d w/d opposite side, ES is very broad (“acting for” two ES Fu1P04 15.40 5.50 5.10 ~5.4 0.36 ~1.06 0.33 ~0.35 saddles plus the E median saddle), and L is longer (nearly Fu1P05 10.90 3.80 ~4.0 4.10 0.35 ~1.03 ~0.37 0.38 as much as E). Fu1P06 9.20 3.50 3.50 3.60 0.38 1.03 0.38 0.39

Remarks - Even though the suture of these Remarks and comparisons- The only known Liassic specimens is almost completely effaced, their coiling, form which seems to share some characters with whorl flattening and ornamentation fit with that of the Furlites is Gemmellaroceras: however, this latter genus holotype, thus their specific attribution can be is more evolute (either in inner and outer whorls), has considered nearly sure. rounded ventral area, and do show some kind of The good preservation of the inner whorls (especially ornamentation (though often rather feeble in internal in the two smallest individuals) enables to follow the moulds); the suture of both genera is simple and with ontogenetic development of the ornamentation since spaced out lobes, but in Furlites it is characterized by its first appearance: the ribs start to reveal from the E lobe in strongly asymmetric position. Anyway, the diameter of about 5 mm; at first they are rather feeble, degree of resemblance seems indicative of affinity at a but they suddenly strengthen, reaching their typical suprageneric level: since Gemmellaroceras is aspect just after an half whorl. At greater diameter the traditionally considered as a Polymorphitidae, we think ventral area raises and ribs become rare, assuming a it permissible to classify in this family Furlites too. nearly sharp aspect, showing even more clearly both However, the absence of ornamentation, as well as the the small spines and the ventral chevron. peculiarities of coiling and ventral area do not allow to relate without reserve Furlites to the most typical Stratigraphic distribution - The material comes from Polymorphitidae (i.e. those included in the nominal the Fu1 lumachella, datable to the Early Pliensbachian subfamily, as Polymorphites Haug, Platypleuroceras (Catriceras Zone). Hyatt, Uptonia Buckman, Dayiceras Spath). For this reason we hypothesize that it represent a distinct subgroup, which will be properly defined only with more data and further studies. Family POLYMORPHITIDAE Haug, 1887 Subfamily to be specified Stratigraphic distribution - Early Pliensbachian Genus Furlites Venturi & Ferri, 2001 (Catriceras Zone).

Type species - Furlites involutus Venturi & Ferri, 2001. Furlites involutus Venturi & Ferri, 2001 Figs. 12a-c; Pl. 2, figs. 13-15, 17 Material - Seven specimens from the Pallareto 1985 Gemmellaroceras sp. ind. - VENTURI, p. 48, fig. 52. Quarry (“Venturi ’78” bed), and nineteen specimens 2001 gen. nov. aff. Gemmellaroceras Hyatt - VENTURI & BILOTTA, from the Furlo Pass (one from the Fu1 lumachella, p. 328, tab. 2. eighteen from the Fu2 lumachella). 2001 Furlites involutus VENTURI & FERRI, p. 134; p. 138, pl. 13, b-d. Emended diagnosis - Small-sized shells, smooth and compressed; involute and relatively broad in the inner Material - Fourteen small-sized specimens. whorls, then less involute. The whorl section is elliptic to a diameter of 3 mm, then it becomes high sub-ellipsoid. On the last quarter of whorl of body chamber the coil can show a sub- trapezoid outline: this happens because it stops its height increase, with a “squeezing” on the peristome. On the phragmocone the ventral area is more or less subacute, but on the last quarter of whorl of body chamber it can become rounded sub-tabular. The peristome has a collar-like constriction (especially evident on the side of the whorl) with two short lateral expansions and a ventral “lappet-like rostrum” with roundish outline (Fig. 13b). Rather simple suture line, with poorly indented lobes, Fig. 12 - Suture lines of Furlites involutus Venturi & Ferri; a) holotype (Fu2F01); among which E is in a strongly asymmetric position b) paratype (Fu2F04); (so much that at times it is very hard to locate with c) paratype (Fu2F07), in which E and L lobes cannot be properly certainty). The remarkable shifting of E brings two A distinguished; all drawn at a diameter of about 8 mm; magnified lobes around the middle of the ventral area, and implies about x 4 (drawings by F. Venturi). 100 Bollettino della Società Paleontologica Italiana, 44 (2), 2005

Measurements - implies that, at a parity of size, some specimens are Number d u h w u/d w/h h/d w/d more or less broad than others, and this fact is Pa78F01 11.6 5.1 3.9 2.7 0.44 0.69 0.34 0.23 particularly evident comparing the Pallareto Quarry Pa78F02 10.9 4.4 3.2 2.4 0.40 0.75 0.29 0.22 individuals Pa78F02, Pa78F03 and Pa78F05 with the Pa78F03 9.9 4.1 3.4 2.6 0.41 0.76 0.34 0.26 Pa78F04 8.2 3.8 2.1 1.9 0.46 0.90 0.26 0.23 remaining exemplars. Pa78F05 7.8 3.2 2.4 2.1 0.41 0.88 0.31 0.27 Fu1F01 11.6 4.8 3.4 0.41 0.29 Stratigraphic distribution - Early Pliensbachian Fu2F01 16.1 7.1 4.4 3.2 0.44 0.73 0.27 0.20 (Catriceras Zone). Fu2F02 16.0 7.0 4.3 3.3 0.44 0.77 0.27 0.21 Fu2F03 15.2 6.5 4.4 3.3 0.43 0.75 0.29 0.22 Furlites sp. Fu2F04 14.2 6.0 5.0 3.4 0.42 0.68 0.35 0.24 Fu2F05 14.1 5.8 4.5 3.2 0.41 0.71 0.32 0.23 Figs. 13a-c Fu2F07 11.9 5.2 4.5 3.2 0.44 0.71 0.38 0.27 Fu2F08 11.2 4.2 4.8 3.5 0.38 0.73 0.43 0.31 Material - Five middle-small sized specimens, Fu2F09 10.1 3.2 4.0 2.5 0.32 0.63 0.40 0.25 including three fragments. Fu2F12 10.2 4.3 3.8 2.6 0.42 0.68 0.37 0.25 4.3 1.9 1.6 2.0 0.44 1.25 0.37 0.47 Measurements - Fu2F10 9.9 4.1 4.0 2.9 0.41 0.73 0.40 0.29 Numberduhwu/dw/hh/dw/d Fu2F13 8.2 2.9 3.3 2.7 0.35 0.82 0.40 0.33 Fu2F16 ~17.0 5.4 3.4 0.63 ~0.32 ~0.20 Fu2F14 8.0 2.3 3.2 2.8 0.29 0.88 0.40 0.35 Fu2F17 ~17.0 ~5.0 3.3 ~0.66 ~0.29 ~0.19 Fu2F11 7.6 2.7 3.1 2.6 0.36 0.84 0.41 0.34 Fu2F18 ~17.0 4.3 2.9 0.67 ~0.25 ~0.17 Fu2F06 13.8 5.5 4.0 3.1 0.40 0.78 0.29 0.22 Diagnosis - Small-sized shells, smooth and Fu2F15 13.1 4.8 4.2 3.0 0.37 0.71 0.32 0.23 compressed, involute and relatively broad in the inner whorls, then evolute. Description - Small-sized smooth shell, more The whorl section is elliptic to a diameter of about compressed and evolute than in F. involutus. 3 mm, then it becomes high sub-ellipsoid and High sub-ellipsoidal whorl section, with rounded or afterwards, on the last quarter of whorl of body slightly subacute ventral area, which is never sub- chamber, sub-trapezoid. tabular. The whole body chamber is long a little more than Body chamber without whorl “squeezing”. a half whorl, and presents a marked growth anomaly, Peristome as for the genus. stopping its height increase and “squeezing” on the Simplified and asymmetric suture, similar to that of peristome. F. involutus. The ventral area is subacute on the phragmocone, but it becomes rounded sub-tabulae on the last quarter Remarks - The attribution of these specimens to of whorl of body chamber. Furlites is based on the general shell aspect, the absence Peristome and suture line as for the genus. of ornamentation, the peristome and suture line conformation. Remarks - Our material is involved by a moderate The differences in the whorl section on the body variability, which we interpret as normal intraspecific: chamber and in the flattening, as well as the lack of it concerns both the degree of compression of the body specimens with preserved inner whorls, render hard chamber (a feature that is very marked especially in to completely appraise the relations of the material at the holotype, here figured in Pl. 2, fig. 17), and the issue with the individuals attributed to the type species. length of the broad inner stage, which ends at a diameter included between about 4 mm and about 8 mm. This Stratigraphic distribution - This form was found in the Fu2 lumachella, datable to the Early Pliensbachian (Catriceras Zone).

Family TROPIDOCERATIDAE Hyatt, 1900 (= ACANTHOPLEUROCERATIDAE Arkell, 1950) Subfamily TROPIDOCERATINAE Hyatt, 1900

Remarks - Traditionally, the genus Tropidoceras Hyatt is considered closely related to Acan- thopleuroceras Hyatt, so much that it is placed in the same subfamily Acanthopleuroceratinae (Arkell et al., 1957; Bremer, 1965; Venturi, 1978; Schlatter, 1980; Fig. 13 - Furlites sp.; Braga & Rivas, 1985; Dommergues, 1987; Cope, 1991; a) lateral view and ventral profile of the specimen Fu2F06; Schlegelmilch, 1992, etc.). Indeed, as demonstrated magnified about x 2; on morphological, sutural and stratigraphic grounds by b) lateral and upper view of the peristome of the fragment Fu2F17; magnified about x 2; Dommergues & Mouterde (1978) and Dommergues c) suture line drawn from the specimen Fu2F06, in which the (1987), the two taxa are linked by a parental relationship, strongly asymmetric position of E can be guessed; magnified since Tropidoceras is the ancestor of about x 4.5 (drawing by F. Venturi). Acanthopleuroceras. Their difference from true F. Venturi, C. Nannarone, M. Bilotta - Liassic ammonite faunas from the Apennines 101

Catriceras-Tropidoceras in the Mediterranean area. We reserve to deepen the issue in the already-mentioned forthcoming paper on the Fu3 lumachella.

Genus Catriceras Venturi, 1978

Type species - Catriceras catriense Venturi, 1978.

Remarks - Even if numerous similarities between Catriceras and Tropidoceras do exist (overall shell morphology; aspect and general style of the ribs; presence of a keel which is reproduced by internal moulds; basic traits of the suture, with enlarged lobes), it is also true that these characters enable to establish a relationship only at a suprageneric level (subfamily or family). In spite of this, many Authors overestimated these resemblances, thus considering Catriceras as a synonym of Tropidoceras (Braga & Rivas, 1985; Dommergues, 1987; Alkaya & Meister, 1995; El Hariri et al., 1996; Dommergues et al., 2000; Rakús & Guex, Fig. 14 - Ontogenetic development of the whorl section of 2002): this interpretation contributed to create Catriceras; drawn from various specimens, all from the Pallareto considerable misunderstandings on the biostratigraphic Quarry (a-c, d2, e: C. catriense; d1: Catriceras sp.1, specimen position of the Early Pliensbachian Apennine faunas. Ca 304 figured by Faraoni et al., 1996, pl. 11, fig. 8-10). Note that the whorl overlapping is constantly poor, the adult stage shows a typical angularity (d2-e), and that the ventral area goes from rounded (a-b) to flattened (c-e); all magnified x 2 (drawings by F. Venturi).

Polymorphitidae (and the absence of evidences proving a phyletic derivation from them) lead Dommergues & Meister (1999) to treat them as belonging to a distinct family, the Acanthopleuroceratidae, which includes also some species ascribable to these two genera only in a broad sense [e.g. “Tropidoceras” stahli (Oppel), and/ or Tropidoceras-Acanthopleuroceras transitional forms]; a similar classification is adopted in Dommergues & Meister (1991), Alkaya & Meister (1995), El Hariri et al. (1996), Dommergues et al. (1997b), Dommergues et al. (2000) as well. Although, generally speaking, we agree with this position, we must observe that the parental relation between Tropidoceras and Acanthopleuroceras does not necessarily imply that they belong to the same subfamily. Chiefly basing on the features of the respective type species (Ammonites masseanus d’Orbigny and Ammonites valdani d’Orbigny), whose important differences were clearly evidenced in Venturi (1978), we believe that the two genera represent separated subfamilies (opinion already expressed in Venturi & Ferri, 2001). We deem therefore it better to consider the Acanthopleuroceratinae a monotypic group, distinct from the one including the genera Tropidoceras and Catriceras (Tropidoceratinae). However some incertitude remains, because the current lack of sections with abundant and continuous Fig. 15 - Ontogenetic development of the whorl section of documentation between the Catriceras and the Tropidoceras demonense (Gemmellaro) (a1-a3) and “T.” zitteli Miltoceras sellae Zones in the Apennines or in other Fucini (b1-b3), coming from Le Gorghe section (erratic specimens from the Metaderoceras gemmellaroi Zone). As can be seen, Tethyan regions prevents us from proving the existence compared to the Fig. 13, the whorl overlapping is greater and the of transitional forms which may testify the derivation keel is less elevated; all magnified x 2 (drawings by F. Venturi). 102 Bollettino della Società Paleontologica Italiana, 44 (2), 2005

the eponymous Zone, which is not represented in the above-mentioned Le Gorghe section. In the light of the last studies on the fauna from the Pallareto Quarry (Venturi & Bilotta, 2001; Venturi et al., 2004) and of the data here presented on the ammonites from the Furlo Pass (remarkable as per preservation and abundance), we are now able to complete the initial observations traced by Venturi (1978), evaluating more clearly the differences which Fig. 16 - Catriceras cf. campiliense (Fucini); a) lateral view; enable to distinguish Catriceras from Tropidoceras, as b) whorl section of the fragment Fu1T06; the outer portion of evidenced in the Tab. 1, where the characters of the the ribs is stronger, and the keel is very elevated; magnified two genera are compared (see also Figs. 14-17). about x 1.5 (drawings by F. Venturi). In addition to the above-listed morphological and sutural differences there are those concerning stratigraphic and geographic distribution: Catriceras is older (until now it is known only from rocks referable to the Early Pliensbachian), and it should be almost exclusively restricted to the Mediterranean Tethys In particular, the frequent (but incorrect) opinion that (central Italy, southern Albania) and its probable Catriceras belongs to the middle Pliensbachian westward prolongation (South America); Tropidoceras (Tragophylloceras ibex Zone, Acanthopleuroceras instead is more recent (the first representatives come valdani Subzone) was caused by two combined factors: from the middle Pliensbachian or from the topmost part 1) the poor documentation once available in the of the Early Pliensbachian), and can be considered Mediterranean Tethys for the first biozone of this stage nearly cosmopolitan. (which, until recently, was inadequately known); On the basis on the explained characters, the species 2) the erroneous report of a presumed Catriceras which we deem to date ascribable to Catriceras are: from the Mount Catria (Le Gorghe section, layer 52) - Catriceras catriense Venturi, 1978 (type species; associated with many Metaderoceras gr. evolutum Umbria-Marche Apennines); (Fucini) (Dommergues, 1987, p. 164). - C. campiliense (Fucini, 1898) (originally called We note that this report is undoubtedly to be Tropidoceras campiliense; Tuscany and perhaps also referred to a “Tropidoceras” zitteli Fucini, species Umbria-Marche Apennine); showing superficial resemblances with Catriceras, but - C. sulcatum (Dommergues, Meister, Bonneau, being exactly more recent. In fact, until proof of the Cadet & Fili, 2000) (originally called Tropidoceras contrary, Catriceras is characteristic and exclusive of sulcatum; southern Albania).

Fig. 17 - Sutures of Catriceras cf. campiliense (Fucini), drawn from various specimens of the Fu1 fauna (a: small specimen Fu1T13; suture drawn at a diameter of about 25 mm; b: fragment Fu1T16; suture drawn at an estimated diameter of about 25-30 mm; c: fragment Fu1T02; suture drawn at an estimated diameter of about 25-30 mm; d: fragment Fu1T09; suture drawn at an estimated diameter of about 25-30 mm; e: specimen of the Nannarone collection Fu1T12; suture drawn at a diameter of about 25 mm; f: fragment of the Nannarone collection Fu1T15; suture drawn at an estimated diameter of about 25-30 mm); all magnified about x 4. As can be seen, E is in a markedly asymmetric position (which at times makes problematic to properly identify the lobes) and the degree of indenting is quite variable (drawing by F. Venturi). F. Venturi, C. Nannarone, M. Bilotta - Liassic ammonite faunas from the Apennines 103

Other forms which are probably to be considered Fu1T10 38.3 17.0 ~12.6 ~7.5 0.44 ~0.60 ~0.33 ~0.20 further distinct species (though still not formalized) of Fu1T11 ~35.0 12.1 5.0 0.41 ~0.35 ~0.14 this genus are: Fu1T13 ~31.2 12.9 11.6 7.4 ~0.41 0.64 ~0.37 ~0.24 Fu1T20 12.7 4.1 4.8 3.7 0.32 0.77 0.38 0.29 - the Apennine specimen Ca 304 erroneously Fu1T22 11.0 3.0 4.0 2.6 0.27 0.65 0.36 0.24 designated in Faraoni et al. (1996, pl. 11, figs. 8-10) as Fu1T23 8.8 4.0 3.8 2.2 0.45 0.58 0.43 0.25 C. catriense; - the Apennine specimen Ca 9 indicated in Faraoni Remarks - Our material is here dubitatively referred et al. (1996, pl. 4, fig. 7; pl. 10, figs. 1-2) as to the taxon described by Fucini (1898) as Tropidoceras “Catriceras” sp.; campiliense, with incertitudes motivated first of all by - the South American specimen figured in some morphological differences. In both cases the Hillebrandt (1990, figs. 3, 6) with the name forms are surely attributable to the genus Catriceras Paltechioceras (?) sp., now correctly attributed to (and in particular to species distinct from C. catriense) Catriceras (Hillebrandt, 2002, and personal for the rib style, their sudden projection, the keel height, communication). the positional asymmetry of E lobe and the L lobe Finally, also the two Canadian specimens figured conformation. However, compared to the ammonites as Tropidoceras species 1 by Smith & Tipper (1996, found at the Furlo Pass, the Tuscan specimen is pl. 11, figs. 2-3) seem ascribable to Catriceras for their apparently more evolute (especially in the inner whorls), ribs, with the typical marked ventral projection; and most of all subacute venter, without flat areas however, this Early Pliensbachian material is too poorly flanking the keel. This aspect might be misleading in preserved to allow accurate comparisons. the taxonomic distinction, being a feature of Tropidoceras rather than of Catriceras, but it must be noted that it is the only anomalous trait, and, exactly Catriceras cf. campiliense (Fucini, 1898) for this reason, we do not deem that it compromise the Figs. 16-17; Pl. 1, figs. 14-16; Pl. 2, figs. 21a-b attribution at a generic level. By now, we are not able to appraise the importance ?1898Tropidoceras campiliense FUCINI, p. 248, pl. 20 (1), figs. of this “unusual” character in the species of Fucini 6a-b. (1898), since it lacks a stratigraphic reference, but also because our material is involved by a conspicuous Material - Twenty-three various-sized specimens variability, which is expressed in the individuation of coming from the Fu1 lumachella, and at least four three “morphotypes”. The most common one (twenty fragments coming from a Fu2 lumachella erratic block. specimens) is characterized by simple suture line, with enlarged L (sometimes possessing quite Measurements - undistinguishable branches) and E shifted from the Number d u h w u/d w/h h/d w/d middle of the ventral area; the coiling is evolute, the Fu1T01 58.0 26.0 17.0 10.6 0.45 0.62 0.29 0.18 whorl section is high with rather flattened sides, the Fu1T07 ~43.5 ~13.5 8.9 ~0.66 ~0.31 0.20 venter has two quite wide flat areas flanking the keel.

Tab. 1 - Detailed comparison between Catriceras Venturi and Tropidoceras Hyatt. 104 Bollettino della Società Paleontologica Italiana, 44 (2), 2005

The second “morphotype” (fragment Fu1T11) has a inner surface of the shell. On the side opposed to that distinctive flat-flanked whorl and markedly tabular where E is shifted, the great development of an A lobe ventral area: this aspect may resemble that of a (which can be as long as E itself) in the ES saddle “Catriceras” sp. figured in Faraoni et al. (1996, pl. 10, occurs, and sometimes an advancement of this saddle fig. 2). The third “morphotype” differs to a greater when it intersect the middle of the ventral area can be extent from the others: it is represented by two slightly observed too. more involute fragmentary specimens (Fu1T07 and Fu1T13), with nearly elliptical whorl section and bended Stratigraphic distribution - The specimens were sides, venter practically without flat areas flanking the found in Fu1 and Fu2 lumachellas, both datable to the keel (in this they are more similar to the Tuscan form), Early Pliensbachian (Catriceras Zone). evident ventro-lateral tubercles, secondary ribs intercalated to the primaries, complex suture (with E apparently in symmetric position). Family LIPAROCERATIDAE Hyatt, 1867 Anyway, in all our individuals the suture has the typical basic conformation of Catriceras, with an Remarks - As often happens, rather different ideas always well-developed L, which is bifid and longer than on the composition of this group exist. In particular, E. Wen this latter lobe is in an asymmetric position according to some Authors (Dommergues et al., 1994; (that is, in the specimens of the first “morphotype”, Blau, 1998, Dommergues et al., 2000), it should include characterized by simple suture), the other sutural also Paramicroderoceras Dommergues, Ferretti & elements undergo a peculiar compensation near the Meister, a genus which we prefer to ascribe to the ventral area, re-equilibrating to uniformly involve the family Eoderoceratidae, subfamily Paramicro-

EXPLANATION OF PLATE 2

Ammonoids from Fu1 and Fu2 lumachellas (Furlo Pass). Unless contrary indications, all specimens are at natural size. A black circle marks the beginning of the body chamber, when it can be distinguished.

Fig. 1 - Juraphyllites libertus (Gemmellaro). Lateral (a) and ventral (b) views of Fu2J01. Provenance: Fu2.

Figs. 2-4 - Sinuiceras planulatum Venturi & Ferri. 2 - Lateral (a) and ventral (b, c) views of holotype, Fu2S01. Provenance: Fu2. 3 - Ventral (a) and lateral (b) views of Fu2S02. Provenance: Fu2. 4 - Lateral view of Fu2S08. Provenance: Fu2.

Figs. 5-10 - Galaticeras canavarii (Fucini). 5 - Lateral (a) and ventral (b) views of Fu2G03. Provenance: Fu2. 6 - Lateral (a) and ventral (b) views of Fu2G05. Provenance: Fu2. 7 - Ventral (a) and lateral (b) views Fu2G04. Provenance: Fu2. 8 - Lateral (a) and ventral (b) views of Fu2G17. Provenance: Fu2. 9 - Ventral (a) and lateral (b) views of Fu2G06. Provenance: Fu2. 10 - Lateral view of Fu2G11. Provenance: Fu2.

Figs. 11-12 - Radstockiceras sp. 11 - Lateral view (a) and whorl section (b) Fu2R02. Provenance: Fu2. 12 - Lateral view of Fu2R01. Provenance: Fu2.

Figs. 13-15, 17 - Furlites involutus Venturi & Ferri . 13 - Lateral view of Furlites involutus Venturi & Ferri (paratype, Fu2F03). Provenance: Fu2. 14 - Lateral view of Furlites involutus Venturi & Ferri (Fu2F04). Provenance: Fu2. 15 - Lateral view of Furlites involutus Venturi & Ferri (Fu2F07). Provenance: Fu2. 17 - Lateral (a), ventral (b) and lateral (c) view of holotype, Fu2F01. Provenance: Fu2.

Fig. 16 - Indeterminate Paramicroderoceratinae. Lateral view of a fragmentary specimens. Provenance: Fu2.

Figs. 18-20 - Pelingoceras pseudocarinatum nov. gen et nov. sp. 18 - Upper ventral (a, x2), ventral (b, x2) and lateral view (c) of Fu2Pe03. Provenance: Fu2. 19 - Terminal part of the body chamber and aperture of Fu2Pe02b), lateral view, x 2. Provenance: Fu2. 20 - Lateral (a) and upper ventral (b, x2) views of Fu2Pe04. Provenance: Fu2.

Fig. 21 - Catriceras cf. campiliense (Fucini). Whorl section (a, x 4) and lateral view (b) of (Fu2T01). Provenance: Fu2.

Fig. 22 - Radstockiceras fastigatum nov. sp. Lateral view of Fu1R02. Only phragmocone. Provenance: Fu1. F. Venturi, C. Nannarone, M. Bilotta - Liassic ammonite faunas from the Apennines Pl.105 2 106 Bollettino della Società Paleontologica Italiana, 44 (2), 2005 deroceratinae for its morphological and sutural features Stratigraphic distribution - In the literature the genus (Venturi et al., 2004). Liparoceras is reported in the Pliensbachian (Uptonia We partially agree with the opinions of Dommergues jamesoni Zone - Amaltheus margaritatus Zone); our & Meister (1999), who, also basing on the existence material comes from the Fu1 lumachella, datable to the of stratophenetic sequences (i.e. stratigraphically Early Pliensbachian (Catriceras Zone). documented evolutive series), ascribe to the Liparoceratidae the following genera: Tetraspidoceras Superfamily ARIETITOIDEA Hyatt, 1875 Spath, Vicinodiceras Trueman, Becheiceras Trueman, Family OXYNOTICERATIDAE Hyatt, 1875 Liparoceras Hyatt, Beaniceras Buckman, Aegoceras Waagen, Oistoceras Buckman, Amaltheus De Montfort, Genus Radstockiceras Buckman, 1918 Pleuroceras Hyatt. However, we think that, with such a great variety of forms in the same family, it could be Type species - Radstockiceras complicatum useful to distinguish at least three subfamilies. Buckman, 1918.

Radstockiceras fastigatum nov. sp. Genus Liparoceras Hyatt, 1867 Figs. 19-20; Pl. 1, figs. 7-8, 10; Pl. 2, fig. 22

Type species - Liparoceras bronni Spath, 1938. Name derivation - From the Latin fastigatum (= pointed, sharp), with reference to the fastigate (i.e. roof- Liparoceras ? sp. shaped) aspect of the ventral area in the internal moulds. Fig. 18a-c Holotype - Fu1R08, middle-sized nucleus with one Material - One fragmentary specimen, with nucleus test layer and partially visible suture line (Pl. 1, fig. 7), (diameter of about 14 mm) and part of outer whorl. housed in the Earth Sciences Department, Università degli Studi di Perugia. Remarks - The nucleus is smooth and clearly spherocone. On the portion of outer whorl the Paratype - Fu1R12, middle-small sized nucleus, ornamentation is formed by ribs crossing the ventral with clearly visible suture line and part of the outer area and small ventro-lateral tubercles. On the outermost whorls (Pl. 1, fig. 10), housed in the Earth Sciences test layer (partially preserved), lyrae extending between Department, Università degli Studi di Perugia. the ribs are evident: within the family this kind of longitudinal ornamentation is characteristic of Type locality - Furlo Pass (Umbria-Marche Liparoceras and close relative genera. Apennines). Our doubt in the generic attribution is due to the shape of the ventral area, which is rounded and very Type section - Grilli Quarry (Furlo Pass), Fu1 elevated, and to the whorl section, which shows its lumachella. maximum thickness on the umbilical edge. The resulting aspect is rather different from that of the generotype Material - Twenty-seven various-sized specimens of Liparoceras, thus making even more uncertain the with only phragmocone, including some fragments. identification at the species level, which we therefore leave undetermined. Measurements - Numberduhwu/dw/hh/dw/d Fu1R02 182.0 39.2 0.22 Fu1R05 85.7 4.0 ~51.0 20.5 0.05 ~0.40 ~0.60 0.24 Fu1R07 75.0 2.6 ~40.0 16.8 0.03 ~0.42 ~0.53 0.22 Fu1R08 65.5 2.9 ~39.5 14.5 0.04 ~0.37 ~0.60 0.22 Fu1R10 49.3 3.9 29.0 11.9 0.08 0.41 0.59 0.24 Fu1R12 38.3 3.2 ~23.9 ~5.2 0.08 ~0.22 ~0.62 ~0.14 Fu1R13 32.5 2.9 18.2 ~7.5 0.09 ~0.41 0.56 ~0.23 Fu1R14 29.0 2.3 16.2 7.1 0.08 0.44 0.56 0.24 Fu1R15 28.0 2.0 16.2 7.7 0.07 0.48 0.58 0.28 Fu1R18 18.8 2.4 10.2 5.1 0.13 0.50 0.54 0.27 Fu1R20 14.9 3.2 6.8 4.0 0.21 0.59 0.46 0.27 Fu1R22 12.9 2.6 6.3 4.1 0.20 0.65 0.49 0.32 Fu1R24 9.8 2.2 4.8 3.6 0.22 0.75 0.49 0.37 Fu1R25 8.6 2.1 3.8 3.0 0.24 0.79 0.44 0.35 Fu1R26 7.2 2.1 3.1 2.5 0.29 0.81 0.43 0.35

Description of the holotype - Clearly involute shell, with high overlapping of the whorls. Whorl section with abrupt slope change at about Fig. 18 - Liparoceras ? sp., fragment Fu1L01; a) lateral view; the half of the flank. b) whorl section; Roof-shaped ventral area, with central relief c) detail of the ventral lyrae; natural size (drawings by F. Venturi). evidenced by a second slope change in the whorl F. Venturi, C. Nannarone, M. Bilotta - Liassic ammonite faunas from the Apennines 107

Fig. 19 - Suture lines (magnified about x 4) and whorl sections (about natural size) of Radstockiceras fastigatum nov. sp.; a) suture from the fragment Fu1R16, drawn at a diameter of about 28 mm; b) whorl section of the same specimen; c) suture from the fragment Fu1R11; d) whorl section of the same specimen, showing that the keel is present only on the test, and it is not reproduced in the internal mould (drawings by F. Venturi).

section and surmounted by a keel which is not except U2, which is well-developed; oblique ES and reproduced in the internal mould. LS1 saddles, with the latter having an A lobe which is Ornamentation with poorly-reliefing, slightly always tilted and shifted towards L. flexuose ribs, which bend backwards connected with the slope change of the flanks and then tend to project Ontogenetic development - The abundance of forward, decreasing their strength and stopping before material enables a good definition of this species, the ventro-lateral edges. represented by exemplars with a diameter ranging from Suture line with quite broad E, slightly shorter than less than 7 mm to about 200 mm; we estimate that the L and with very divergent main branches, directed adults, with their whole body chamber, might have towards L itself; small umbilical lobes. reached at least a diameter of 250-300 mm. As in all other Radstockiceras for which the Diagnosis - Very involute adult shell, typical for the ontogeny is known, the shell is initially broad and genus. relatively evolute, but afterwards it tend to narrow and The whorl section assumes an increasingly close more and more. In the first growth stages the polygonal aspect during the ontogeny, until it shows a whorl is involved by spaced umbilical reliefs, which slope change at about the half of the flank, so that the probably are to be considered the initial form of subsequent whorl overlaps the preceding one for less ornamentation. The keel seems to appear rather than the 50%. This outline becomes gradually more precociously, at least from the diameter of 10 mm, and, and more evident starting from the diameter of about as already stated in the diagnosis, it undergo a raising 10 mm, that is when the ribs first appear. during the individual growth. At the same size the first The ventral area is roof-shaped and rather pointed; true ribs appear, but they become clearly evident only when the test is preserved, a keel connected with the after the diameter of 30 mm, as well as happens for central relief of the internal moulds can be observed. the characteristic slope change of the whorl sides. This is formed by a thickening of the test itself, Starting from the diameter of about 150 mm, the appearing very low and blunt on inner whorls, but ornamentation weakens, tending to cancel. afterwards it raises, and it seems that it may persist as In this species, the precocious acquisition of the far as the body chamber. typical features of Radstockiceras (such as keel not The ornamentation is constituted by very enlarged reproduced in internal moulds and ornamentation) may and poorly reliefing ribs, slightly flexuose, which bend suggest a certain morphological stability, indicating that backwards connected with the slope change of the at that time this genus represented a well-established flanks and then tend to project forward, decreasing taxonomic and biologic entity. In turn, this might mean their strength and stopping before the ventro-lateral that this was a taxon already stabilized by the terminal edges. Secondary ribs are apparently absent and, part of the Sinemurian and survived until the exceeding a diameter of 150 mm, ribs disappear. Pliensbachian. This accords both with the absence of The suture line is characteristic of the genus, with the signs typical of an important environmental crisis E long one half or as long as L; small umbilical lobes, (i.e. numerous extinctions) for the Sinemurian- 108 Bollettino della Società Paleontologica Italiana, 44 (2), 2005

Fig. 20 - Ontogenetic development of Radstockiceras fastigatum nov. sp.; the characteristic angularity of the flanks is already evident from the diameter of about 12 mm; a) lateral view and ventral profile of the small specimen Fu1R25; b) lateral view and ventral profile of the small specimen Fu1R19 (Nannarone collection); c) lateral view and ventral profile of the nucleus Fu1R15; d) lateral view (partially restored) and whorl section of the fragment Fu1R11; all specimens are at natural size (drawings by F. Venturi).

Pliensbachian boundary and with the literature reporting primary and secondary ribs reaching the ventro-lateral the origin of this genus already in the latest Sinemurian edges, and indeed also for this reason it seems better (Donovan et al., 1981; Donovan, 1994; Dommergues to treat them as R. gr. complanosum: they differ from et al., 1994, 2000). the Furlo Pass forms for flattening, coiling, ventral area and ornamentation. Remarks and comparisons - This form can be The Albanian specimens reported by Dommergues distinguished quite clearly from most of the known et al. (2000, figs. 5.5, 6.3) as Radstockiceras sp. (form Radstockiceras, starting from the type species of the A) show fair good resemblance with ours, but they genus, R. complicatum, which lacks ornamentation, have different ventral area (generally much broader) and do not have roof-shaped ventral area. and whorl without slope change at the half of the flanks. Compared to our species, R. gemmellaroi (Gemmellaro) has weaker ornamentation, which is Stratigraphic distribution - Early Pliensbachian present only on the test (the internal mould is smooth), (Catriceras Zone). pointed ventral area (not fastigate), smaller whorl overlapping, and different stratigraphic provenance Radstockiceras sp. (probably upper part of the Miltoceras sellae Zone). Pl. 2, figs. 11-12 In the type specimen of R. complanosum (figured in Howarth, 1962 and Schlegelmilch, 1992) the slope Material - Three small-sized specimens (nuclei), change at the half of the flank lacks, ribs have different one of which with part of the outer whorls. shape, do not bend backwards, and originate secondary ribs ending on the ventro-lateral edge; concerning this Measurements - species, Howarth (2002) believes that R. complanosum Numberduhwu/dw/hh/dw/d is a synonym of R. buvignieri, but we do not agree Fu2R01 13.9 4.0 6.2 3.9 0.29 0.63 0.45 0.28 with this opinion, chiefly because the ornamentation Fu2R02 11.5 3.1 5.3 3.8 0.27 0.72 0.46 0.33 Fu2R03 10.5 2.9 4.9 3.2 0.28 0.65 0.47 0.30 of R. complanosum is very peculiar, and it is clearly visible in the internal moulds (whereas in R. buvignieri Description - Involute shell, with subacute ventral it is almost smooth). area in the first whorls; starting from at least a diameter As to R. buvignieri (d’Orbigny) (which type is of 9-10 mm the venter bears an elevated keel, which is photographed in Fischer, 1994) our specimens have not reproduced in the internal mould. smaller overlapping and are clearly ornated both on the Whorl with parallel flanks for most part of its height, test and in internal moulds. then gently converging towards the ventral area. Overlapping and ornamentation differences can be Ornamentation nearly absent or very faint: up to a observed also in regards to the R. aff. numismale diameter of about 10-13 mm it is formed by broad sub- (Oppel) of Faraoni et al. (1996), which shows evident radial primary ribs, hardly relieved, which afterwards secondary ribs. become falcate and weak, with a much accentuated The four individuals found in “Venturi ’78” bed of ventro-lateral portion. Around a diameter of 30 mm, the Pallareto Quarry (two of them were figured on the ventro-lateral edge slight proverse secondary respectively in Venturi, 1978 and in Venturi & Ferri, ribs are evident. 2001), and originally classified as R. gr. numismale have The suture line is not visible. F. Venturi, C. Nannarone, M. Bilotta - Liassic ammonite faunas from the Apennines 109

Remarks and comparisons - The material at issue developed ventral rostrum (formed as the continuation seem to clearly present the characters of the genus of the keel), surmounted by a large “ear-like” lateral Radstockiceras as per coiling, kind of ornamentation, protuberance. whorl section; the documentation, however, is not The suture is rather simplified, with E possessing a sufficient to detailed comparisons enabling an adequate shallow median saddle and long about one half of L; L specific assignment. markedly trifid, with equal-sized lobules; ES and LS1 Among the few small-sized specimens reported in saddles of the same size, both with a single tooth-like the literature, the only one that might show some A lobe each, vertically placed in ES, slightly tilted resemblance with ours is the Radstockiceras sp. (form towards U2 in LS1; vertical U2, quite large, but less A) figured by Dommergues et al. (2000, fig. 5.5), but long than L. for it a different-shaped whorl section is described. Remarks and comparisons - The character Stratigraphic distribution - The specimens were combination expounded in the diagnosis, including the found in the Fu2 lumachella, datable to the Early style of the constrictions, is very singular, and we do Pliensbachian (Catriceras Zone). not know that it has ever been described in the literature for other Liassic ammonites. The small size of the shell, the absence of Order uncertain ornamentation and some aspects of the suture might Family to be specified vaguely recall Furlites, but the coiling, the style of the constrictions and the features of the peristome (which Genus Pelingoceras nov. gen. is apparently a rather specialized structure), are very different. Also due to these reasons we preferred to Type species - Pelingoceras pseudocarinatum nov. leave uncertain the suprageneric position. sp. Included species - Pelingoceras pseudocarinatum Name derivation - From Pelingo, locality near the nov. sp. (type species by original designation). Furlo Pass, and from the Greek kéras (= horn, due to the resemblance with the ram horns of the ancient god Zeus Ammon, traditionally adopted as “termination” in Pelingoceras pseudocarinatum nov. sp. many ammonite names). Fig. 21; Pl. 1, figs. 17-19; Pl. 2, figs. 18-20

Type locality: Furlo Pass (Umbria-Marche Name derivation - From the Greek pseudós (= false) Apennines). and the Latin carina (= keel), with reference to the keel of the body chamber which is not reproduced in Typical beds: Spathic lumachella of the “Corniola” internal moulds. in “massive” facies (Fu1 assemblage); Early Pliensbachian. Holotype - Fu1Pe01, specimen with body chamber (Pl. 1, fig. 17), housed in the Earth Sciences Material - Twenty-one small-sized specimens, Department, Università degli Studi di Perugia. attributed to a single species; all are preserved as spathic internal moulds, sometimes with traces of pseudo-test; Paratype - Fu1Pe04, specimen with only of them, seventeen come from the Fu1 lumachella, and phragmocone (Pl. 1, figs. 18-19), housed in the Earth four were found in the Fu2 lumachella. Sciences Department, Università degli Studi di Perugia. Five more specimens from the Fu1 lumachella are dubitatively assimilated to this genus. Type locality - As for the genus.

Diagnosis - Small-sized shells, involute in the inner Type section - Grilli Quarry (Furlo Pass), Fu1 whorls, then moderately evolute. lumachella. Sub-ogival whorl section, higher than wide. The ventral area is rounded to the diameter of about Material - Twenty-one small-sized specimens. 6-10 mm, then, on the body chamber (which is long a little more than an half whorl) it becomes subacute and shows a blunt keel, which is not reproduced in internal moulds. As to the ornamentation, the shell is smooth, but on the terminal part of the body chamber thin growth striae, bended forward to reproduce the shape of the peristome, are evident. On the flank of the last half whorl two or three biconvex constrictions are well visible too (apparently also when the test is preserved), Fig. 21 - Suture line of Pelingoceras pseudocarinatum nov. gen et nov. sp., drawn from the small specimen Fu1Pe03; E is shifted stopping in connection with the keel. from the middle of the ventral area, and is shorter than L, which The peristome is preceded by a deep constriction, is trifid; after U2 two lobules can be seen, perhaps representing with wart-like edges, and it is constituted by a well- U3; magnified about x 5 (drawing by F. Venturi). 110 Bollettino della Società Paleontologica Italiana, 44 (2), 2005

Measurements - Ornamentation apparently absent or represented only Number d u h w u/d w/h h/d w/d by some poorly-evident constrictions (not present in Fu1Pe01 ~17.6 6.8 6.2 4.2 ~0.39 0.68 ~0.35 ~0.24 the specimen figured). Fu1Pe03 16.1 7.2 ~5.2 4.4 0.45 ~0.85 ~0.32 0.27 The suture is not visible. Fu1Pe04 12.2 4.3 4.0 3.0 0.35 0.75 0.33 0.25 Fu1Pe06 11.2 5.1 4.2 3.2 0.46 0.76 0.38 0.29 Fu1Pe07 11.2 4.5 4.4 3.2 0.40 0.73 0.39 0.29 Remarks and comparisons - The assimilation (even Fu1Pe08 11.1 4.4 4.2 3.0 0.40 0.71 0.38 0.27 though doubtful) of this form to Pelingoceras is based Fu1Pe09 11.0 4.2 4.2 3.0 0.38 0.71 0.38 0.27 on the general shell aspect, the conformation of the Fu1Pe17 10.2 3.2 3.3 2.8 0.31 0.85 0.32 0.27 ventral area and the absence of true ornamentation. Fu1Pe18 9.0 3.6 3.5 2.4 0.40 0.69 0.39 0.27 The fragment Fu1Pe22 is the only specimen for which Fu1Pe19 ~9.0 4.6 3.5 ~0.51 ~0.39 Fu2Pe01 13.0 5.1 4.2 3.2 0.39 0.76 0.32 0.25 a constriction is clearly visible: its style seems Fu2Pe02 11.0 4.5 3.5 2.9 0.41 0.83 0.32 0.26 resemblant that described for P. pseudocarinatum; in Fu2Pe03 10.9 4.9 3.2 2.9 0.45 0.91 0.29 0.27 the remaining exemplars this character is poorly or not Fu2Pe04 10.2 4.3 3.7 ~3.0 0.42 ~0.81 0.36 ~0.29 evident, but this perhaps might depend on their less good state of preservation. Description of the holotype - Small-sized shell, The differences as per coiling (much greater than smooth, involute in the inner whorls, then moderately that described for P. pseudocarinatum), whorl evolute. overlapping (apparently smaller) and keel development Sub-ogival whorl section, higher than wide. (later and less elevated), as well as the lack of data on The ventral area is rounded to the diameter of about peristome and suture line, make difficult for us to 10-11 mm, then it gradually becomes subacute, with a completely appraise the relations of the material at issue blunt but rather elevated keel, which is not reproduced with the individuals surely referred to Pelingoceras. in the internal mould. As per size, degree of evolution and stratigraphic Starting from the diameter of about 9-10 mm three position we notice some resemblance between these biconvex constrictions can be observed, stopping in forms and the English ammonite figured by Meister et connection with the keel. al. (2003, pl. 2, figs. 16-17) as Leptonotoceras sp. (Wine The suture is not visible. Haven section, bed 1018). However, in this specimen the ventral area, more or less acute, is crossed by a Diagnosis - As for the genus. thin ribbing (Meister, personal communication), a feature completely absent in our individuals. Moreover, Stratigraphic distribution - Early Pliensbachian we think that neither the ammonite of bed 1018 from (Catriceras Zone). Wine Haven, nor our material seem attributable to the genus Leptonotoceras Spath, since forms safely “Pelingoceras” sp. referable to this taxon are known only in the Sinemurian Figs. 22a-b of the Boreal Paleoprovince (e.g. the L. emersoni Hoffmann figured in Blau et al., 2000, figs. 3, 8, 11- Material - Five small-sized specimens. 12; or the Leptonotoceras sp. figured by Meister et al., 2003, pl. 2, figs. 18-19), and they have at least Measurements - different coiling and height increase. Number d u h w u/d w/h h/d w/d Fu1Pe15 10.3 4.5 3.4 0.44 0.33 Stratigraphic distribution - This form was found Fu1Pe21 10.1 5.0 2.9 2.6 0.50 0.90 0.29 0.26 in the Fu1 lumachella, datable to the Early Pliensbachian Fu1Pe22 ~10.0 2.5 2.5 1.00 ~0.25 ~0.25 (Catriceras Zone). Description - Small-sized shells, rather evolute, laterally compressed. Sub-ogival whorl section, higher than wide. Order uncertain The ventral area is at first rounded, then subacute, Family to be specified with a blunt and low keel, lending to the whorl section a peri-ventral “slimming”. Genus new undetermined Pl. 1, figs. 13a-b

Material - Two specimens, of which one is perfectly entire and with preserved peristome.

Measurements - Numberduhwu/dw/hh/dw/d Fu1X01 15.0 4.9 5.1 3.9 0.33 0.76 0.34 0.26

Description - Completely smooth shell, rather Fig. 22 - “Pelingoceras” sp., specimen Fu1Pe20; involute. Subacute ventral area, with a blunt and not a) lateral view; much elevated keel on the last half whorl. The b) ventral view; magnified about x 1.5 (drawings by F. Venturi). peristome, marked by a constriction, is characterized by a well-developed rostrum (formed as the F. Venturi, C. Nannarone, M. Bilotta - Liassic ammonite faunas from the Apennines 111 continuation of the keel) and two weak lateral lobe) are presented ambiguously. Anyway, we deem expansions. appropriate to consider this forms as the representatives The suture is not visible. of at least a new family.

Remarks - We do not have enough elements to determine the systematic position of this form. Its Genus Sinuiceras Venturi & Ferri, 2001 features do not suggest close relationships with other known taxa. The peristomal rostrum, formed as the Type species - Sinuiceras planulatum Venturi & continuation of the keel, recalls that of Pelingoceras, Ferri, 2001. but apparently lacks the characteristic “ear-like” expansions of the latter (which, furthermore, has a very Diagnosis - Platycone shell, involute or moderately different-shaped shell), and the keel itself is less evident. involute, with rather rapid increase in the whorl height; whorls with a considerable overlapping, about 1/2. Stratigraphic distribution - This form was found Sub-ogival whorl section, much more high than in the Fu1 lumachella, datable to the Early Pliensbachian wide, with narrow ventral area. (Catriceras Zone). Completely smooth phragmocone; body chamber with sinuous constrictions (about 6 per whorl), which present a biconcave outline on the flank and cross the Order uncertain ventral area; sometimes on the flank some weak striae Family SINUICERATIDAE nov. fam. are visible. Quite simple suture line, with spaced and poorly- Type genus - Sinuiceras Venturi & Ferri, 2001. branched lobes: L longer than E; large U2 lobe (as a rule as long as L), followed by three or four small Diagnosis - Platycone shell, compressed, with outer umbilical lobes, placed on an oblique “descending” line whorls from involute to moderately involute. (suspensive lobes or “pseudo-sutural lobe”); LS1 saddle Sub-ogival whorl section, higher than wide. much more advanced and wide than ES. Smooth phragmocone; body chamber in almost all cases ornated by biconcave constrictions, and in some Stratigraphic distribution - Early-middle forms also by thin hemi-ribs (formed by bundling of Pliensbachian (from the Catriceras Zone to at least the striae) ending in short cuneiform tubercule-spines. lower part of the Metaderoceras gemmellaroi Zone). Quite simplified suture line, with L lobe nearly as long as E or a little more; large U2 as long as L or a Included species - Sinuiceras planulatum Venturi & little less; the subsequent umbilical lobes are simple and Ferri, 2001 (type species by original designation), placed on an oblique line (so as to appear slightly Sinuiceras planatum (Rakús & Guex, 2002). suspensive); LS1 saddle much more advanced than ES; sub-lituid inner lobe, sometimes apparently provided of septal endings (i.e. its terminal branches embrace Sinuiceras planulatum Venturi & Ferri, 2001 the foregoing I lobe). Figs. 23a-b; Pl. 2, figs. 2-4

Remarks - The original placing of the genus 1985 gen. nov. aff. a Gemmellaroceras Hyatt - VENTURI, p. 48- Sinuiceras within the family Polymorphitidae (subfamily 49, fig. 53. Polymorphitinae) was principally due to the apparent 2001 Sinuiceras planulatum VENTURI & FERRI, p. 130; p. 36, fig. lack of more suitable groups for its housing (Venturi & 20a. 2001 Sinuiceras laevispira VENTURI & FERRI, p. 138, pl. 13, fig. Ferri, 2001), but now we believe that this f. “convenience” position is no more tenable. In fact, it must be noted that no early-middle Liassic Material - Forty middle-small sized specimens. eoderoceratoid has constrictions, which are instead fairly widespread both among the Phylloceratida (for instance in the Juraphyllitidae) and among various “lytoceratines” (e.g. Analytoceras, Holcolytoceras, Aegolytoceras, Audaxlytoceras, Galaticeras) of the same time interval. Basing on recent studies on our material, also in relation to the new form (which will be treated in a forthcoming publication) erroneously ascribed by Rakús & Guex (2002) to Gorgheiceras Venturi & Ferri, we think that Sinuiceras belongs to a suprageneric taxon of uncertain position. It is currently difficult to state with certainty whether this group is related to the Phylloceratida or to the Psiloceratida (and in particular to the “lytoceratines”), Fig. 23 - Ontogenetic development of Sinuiceras planulatum since in the specimens of Rakús & Guex (2002), the Venturi & Ferri; a) lateral view and whorl section of the small specimen Fu2S40; sutural characters (which we deem decisive from this b) lateral view, whorl section and ventral profile of the specimen point of view, especially concerning the aspect of the I Fu2S04; all are magnified about x 2.3 (drawings by F. Venturi). 112 Bollettino della Società Paleontologica Italiana, 44 (2), 2005

Measurements - The basal assemblage of the Catriceras Zone is Number d u h w u/d w/h h/d w/d represented by the Catriceras catriense bioevent Fu2S01 19.1 5.8 7.3 4.2 0.30 0.58 0.38 0.22 (“Venturi ’78” bed, Pallareto Quarry), followed in Fu2S02 17.1 5.9 5.9 3.5 0.35 0.59 0.35 0.20 chronological order by the two new assemblages Fu1 Fu2S03 14.0 4.9 5.6 3.2 0.35 0.57 0.40 0.23 and Fu2 (Furlo Pass): compared to the preceding Fu2S16 11.8 3.9 4.3 2.8 0.33 0.65 0.36 0.24 Fu2S04 11.2 3.6 4.9 3.8 0.32 0.78 0.44 0.34 Pallareto fauna, the first new assemblage contains at Fu2S25 11.1 4.0 4.2 2.8 0.36 0.67 0.38 0.25 least two original forms (Caleites and Pelingoceras), Fu2S17 11.0 3.8 5.0 3.1 0.35 0.62 0.45 0.28 while the second one in addition shows the considerable Fu2S19 10.9 3.8 4.7 2.9 0.35 0.62 0.43 0.27 novelty of Sinuiceras. The uniting elements of these Fu2S05 10.6 3.5 4.5 2.9 0.33 0.64 0.42 0.27 assemblages, i.e. genera present in all three faunas, are Fu2S21 10.5 3.1 4.5 2.9 0.30 0.64 0.43 0.28 Furlites (which nevertheless can be considered “typical” Fu2S20 10.4 3.9 4.4 2.8 0.38 0.64 0.42 0.27 Fu2S30 9.9 3.2 4.1 2.5 0.32 0.61 0.41 0.25 only of Fu2), Galaticeras (still occurring in beds Fu2S32 9.8 3.1 4.2 2.6 0.32 0.62 0.43 0.27 referable to the middle Pliensbachian) and, obviously, Fu2S26 9.5 3.9 3.9 2.8 0.41 0.72 0.41 0.29 Catriceras. Therefore, as a whole, the Pallareto, Fu1 Fu2S28 9.4 3.1 4.0 2.3 0.33 0.58 0.43 0.24 and Fu2 ammonite faunas show the remarkable wealth 3.4 1.5 1.6 1.3 0.44 0.81 0.47 0.38 of forms marking the lower part of the first Apennine Fu2S33 9.2 3.1 3.6 2.5 0.34 0.69 0.39 0.27 Pliensbachian biozone. The presence in this time interval Fu2S34 9.0 2.8 3.6 2.4 0.31 0.67 0.40 0.27 of some completely new taxa testifies to our poor Fu2S39 8.1 2.8 3.2 2.1 0.35 0.66 0.40 0.26 Fu2S37 8.0 2.8 3.2 2.2 0.35 0.69 0.40 0.28 knowledge of Tethyan Liassic ammonoids, whose Fu2S40 7.5 2.7 3.6 2.1 0.36 0.58 0.48 0.28 biodiversity is still far from being exhaustively understood. Remarks - The inner whorls are quite involute, with The differences with the faunas of other areas are round section and more than 1/3 of whorl overlapping. remarkable (perhaps partly due to the scarcity of studies The specimen Fu2S25 seems to have a trace of the and/or discoveries), and we currently feel that the peristome: from what can be guessed it is rather simple, Apennine assemblages may represent a and follows the pattern of the constrictions of the body paleobiogeographic entity separate from other more or chamber, which would be long 3/4 of whorl. less neighbouring regions (e.g. Spain, North Africa). The specimen Fu2S03 was figured in Venturi & Ferri However, the biostratigraphic data and the (2001, p. 130, pl. 13, f) as S. laevispira, because the paleogeographic reconstruction available for the middle- spathic internal mould does not seem to have western portion of the Neotethys (Alpine Mediterranean constrictions: a more careful inspection lead us to Tethys or Mediterranean Tethys of Meister & Stampfli, discover their presence, although faint, therefore we 2000) do not allow us to completely appraise the deem no more appropriate to ascribe this exemplar to a importance of this separation. Anyway, it seems that, different species from S. planulatum. in this region, only a discontinuous faunal exchange occurred between the “Alpine” sector (including Stratigraphic distribution - By now, this species Austroalpine, Southern calcareous Alps, Apennines, was found only in the Fu2 lumachella, datable to the Sicily and Apulian plate; perhaps also Albania and Ionian Early Pliensbachian (Catriceras Zone). Greece) and the westernmost one (Betic Cordillera and North Africa). Considering also the sedimentary discrepancies CONCLUSIONS (both quantitative and qualitative) existing between the various portions of the middle-western Neotethys, this This study of the Fu1 and Fu2 assemblages allows partial isolation and the related faunal differences have more complete characterization of the Early repercussions on the correlatability of the Pliensbachian ammonite faunas in the Apennine, biostratigraphic boundaries, either compared to the through the description of some new taxa and better standard Boreal and sub-Boreal zonation (see for definition of already-reported genera as Caleites, example Dommergues et al., 1997a) or to the schemes Furlites, Sinuiceras and especially Catriceras. The established within the Tethys itself (Braga et al., 1982, clearer distinction of the latter from Tropidoceras has 1984). enabled us to propose the use of the new Catriceras Notwithstanding these limitations, the assemblages Zone for the beginning of the Pliensbachian in the studied in this paper seem to support the idea that the Apennine, replacing the “Tetraspidoceras faunal renewal connected with the Sinemurian- quadrarmatum” Zone of Faraoni et al. (1996). Pliensbachian boundary was not a simple turnover, and, Compared to the schemes generally adopted for the at least for the Tropidoceratidae and Polymorphitidae, biostratigraphy of the Mediterranean Tethys, this it can be interpreted as an adaptive radiation. Our data represents a considerable progress: in fact, we believe suggest that this was mainly “triggered” by a change that the zonation defined by Braga et al. (1982, 1984) in the paleogeographic setting (seaway opening) more for the Betic Cordillera (southern Spain) is not accurate than by a biological crisis in the strict sense. enough, chiefly because its base is not well- Therefore, the appearance of several new taxa documented, and its first marker (Gemmellaroceras witnessed in the Apennine successions (both if it was aenigmaticum) is not completely adequate, as in our true local origin, or the immigration of forms originated area it only occurs from the second biozone of the outside the Mediterranean Tethys) is a remarkably Early Pliensbachian. important datum, since it allows us to characterize a F. Venturi, C. Nannarone, M. Bilotta - Liassic ammonite faunas from the Apennines 113 time interval which, until now, was very poorly von Ankara (Türkei). Neues Jahrbuch für Geologie und understood. Paläontologie Abhandlungen, 122 (2): 127-221. Buckman S.S. (1919-1930). Type Ammonites. Vol. III-VII, 358 pp., Wheldon & Wesley, London. Cantaluppi G. & Savi A. (1968). Le ammoniti di Molino Grasso ACKNOWLEDGEMENTS d’Olona (Varesotto). Riflessi biostratigrafici sul Domeriano ed il suo limite superiore. Atti della Società Italiana di Scienze We would like to thank Dr. Giovanna Carla Pozza (Università Naturali e del Museo Civico di Storia Naturale, 108 (3): 14- degli Studi di Perugia) for her help in the processing of the figures 261. and Dr. Carlo Ricci (Università degli Studi di Perugia) for his Cope J.C.W. (1991). Ammonite faunas of the Ammonitico Rosso interesting observations on the sedimentological features of the of the Pontide Mountains, Northern Anatolia. In Farinacci rocks from which the studied faunas come. A., Ager D.V. & Nicosia U. (eds), Geology and Paleontology A grateful acknowledgement also to: Dr. Christian Meister of Western Pontides, Turkey. Jurassic-Early Cretaceous (Muséum d’histoire naturelle, Genève) for his indications on the stratigraphy, tectonics and paleogeographic evolution. English ammonoids ascribed to Leptonotoceras; Dr. Jean-Louis Geologica Romana, 27: 303-325. Dommergues (Université de Bourgogne) for his review of the Dommergues J.-L. (1987). Les Acanthopleuroceras, un genre manuscript and his explanations on the affinity between endémique euro-occidental issu d’une famille téthysienne; Derolytoceras and Lytoceras; Dr. Mike K. Howarth (The Natural étude de leur divergence évolutive. In L’evolution chez les History Museum, London) and Prof. Desmond T. Donovan ammonitina du Lias moyen (Carixien, Domerien basal) en (University College, London) for their comments and interest Europe occidentale. Documents des Laboratoires de manifested on the relationships of Sinuiceras; Prof. F. Cecca géologie, Lyon, 98: 156-173. (Université Pierre et Marie Curie, Paris) for his review of the Dommergues J.-L. (2002). 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