Skip to main content

Enrico Borghi

  • Biodiversity Journal, 8 (2): 315-389 - MONOGRAPH

    Paolo Stara & Enrico Borghi
    Revision of the genus Amphiope L. Agassiz, 1840 (Echinoidea Astriclypeidae) with the description of a new species from the Miocene of France

    ABSTRACT
    The taxonomy of Amphiope L. Agassiz, 1840 (Echinoidea, Astriclypeidae), an echinoid distributed in the Oligo-Miocene of Central and Southern Europe, is largely unresolved since the description of most species attributed to this genus was based only on the external morphological features, while important characters, such as the oral plating and the internal support system, were poorly illustrated or completely omitted. Additionally, the type material of some species was missing or badly preserved and geographical/stratigraphical information about the type-locality was unclear. This was the case also for Amphiope bioculata (Des Moulins, 1837), the type species of the genus. The poor definition of the earlier described species of Amphiope prevented comparison with fossils from other localities and ages, subsequently attributed to this genus. A large part of the earlier species of Amphiope, key-taxa for the resolution of the complex taxonomy of this genus, are herein revised by modern methods. For this purpose, the type material available in public institutions has been re-examined and, when possible, new topo-typic material has been collected. As a result, the morphological description of A. bioculata has been completed based on fossils from the Middle Miocene of Hérault (France), which is here considered as the type area. The redefinition of the type species allowed to extend comparison and taxonomic discussion to other species earlier attributed to Amphiope. Seventeen species are herein confirmed as valid and maintained in the genus Amphiope. Three additional species so far attributed to Amphiope have been transferred to the genus Paraamphiope Stara et Sanciu, 2014: P. agassizi (Des Moulins in Cotteau, 1865), P. cherichirensis (Thomas et Gauthier, 1889) and P. baquiei (Lambert, 1907). Amphiope boulei Cottreau, 1914, has been assigned to the genus Sculpsitechinus Stara et Sanciu, 2014. Amphiope romani n. sp. is described on the basis of a sample from the Serravallian-Tortonian of Touraine (France); it is distinguished mainly by the periproct very close to the posterior margin and the lack of sinus in correspondence of the frontal ambulacra.

  • Biodiversity Journal, 6 (1): 393-400 - MONOGRAPH

    Paolo Stara, Federico Marini, Giuseppe Carone & Enrico Borghi
    Distribution of two Amphiope L. Agassiz, 1840 (Echinoidea Clypeasteroida) morphotypes in the Western-Proto-Mediterranean Sea
    Proceedings of the 2nd International Congress “Speciation and Taxonomy”, May 16th-18th 2014, Cefalù-Castelbuono (Italy)

    ABSTRACT
    Several species belonging to the genus Amphiope L. Agassiz, 1840 (Echinoidea Astriclypeidae) from the Mediterranean Oligo-Miocene have been synonymised with A. bioculata (Des Moulins, 1835), the type-species of the genus, based on the interpretation given by Philippe (1998) as a taxon characterized by a large amount of morphological variability. A recent study introduced the characters of the internal test structure and the plating patterns as taxonomic tools in this genus. That paper indicated the occurrence of at least five different species in the examined sample from the Oligo-Miocene of Sardinia, thus pointing to a previous overestimation of the variability-range of the type-species and to the need of a review of the largely unresolved taxonomy of Amphiope. According to a recent study, Amphiope is considered as a shallow-water echinoid, inhabiting sandy bottoms with high hydrodynamic energy; so it represents a coastline marker, useful for the study of the paleo-geographic changes occurred in the Proto-Western-Mediterranean during the Miocene. The diffusion and speciation of Amphiope were highly influenced by those changes. In particular, the speciation rate of this genus was likely favored by the occurrence of isolated populations created when islands (e.g.: Baleares, Calabria, Corse, Kabylies, Sardinia) separate from the mainland, above all in the western part of that Basin, because of the opening of the Balearic Basin during the Late Oligocene-Early Miocene and of the Tyrrhenian Sea during the Burdigalian-Tortonian (references in this work). Two main morphotypes of Amphiope sensu Stara & Sanciu (2014), developed in the Western Mediterranean from the late Oligocene to the late Miocene. They are herein called the “bioculata” group, characterized by roundish to broad elliptical lunules with major diameter/minor diameter ratio (SI) < 1.59, and the "nuragica" group, with more or less narrow lunules and SI > 1.6. According to this authors, most Miocene forms with narrow elliptical lunules would derive from A. nuragica (Comaschi Caria, 1955), late Oligocene-early Miocene of Sardinia, the most archaic form so far known of this genus. The forms belonging to the “bioculata” group likely derived from a different common ancestor bearing round to broad ovoidal lunules. “A. bioculata” described by Cottreau (1914), from the Burdigalian (Philippe, 1998) of Saint Cristol (Nissan, Herault, France), is so far the most ancient known form belonging to this group. This work proposes a possible speciation sequence of the “nuragica” group.

  • Biodiversity Journal, 5 (2): 245-268 - MONOGRAPH

    Paolo Stara & Enrico Borghi
    The echinoid genus Amphiope L. Agassiz, 1840 (Echinoidea Astriclypeidae) in the Oligo-Miocene of Sardinia (Italy)

    ABSTRACT
    The records of the genus Amphiope Agassiz, 1840 (Astriclypeidae) from Sardinia are revised on the basis of 110 specimens, collected from 15 localities of Oligo-Miocene age. Since the morphological characters stated in the literature to distinguish the species of Amphiope described in this region cannot provide a clear separation between them, analyses of the plate patterns and of the internal test structure are introduced as taxonomic tools useful for species-level taxonomy in this genus. Five different species of Amphiope are identified. Three of the six species erected on the basis of fossil material from Sardinia are confirmed as valid: Amphiope lovisatoi Cotteau, 1895, A. montezemoloi Lovisato, 1911 and A. nuragica (Comaschi Caria, 1955). Two additional species are left in open nomenclature. The morphological descriptions and the stratigraphical distributions are updated and improved.

  • Biodiversity Journal, 11 (1): 263-287

    Enrico Borghi & Paolo Stara
    Revision of the genus Heterobrissus (Echinoidea), with a new species from Sardinia, and redefinition of Heterobrissus niasicus (Doderlein, 1901) in Echinopneustes n. gen.
    https://doi.org/10.31396/Biodiv.Jour.2020.11.1.263-287
    https://www.zoobank.org/References/70efa584-49ce-43a3-bd81-a9c5e34d992d

    ABSTRACT
    Morphological characters previously unknown in Heterobrissus montesi Manzoniet Mazzetti, 1878, the type-species of the genus Heterobrissus Manzoniet Mazzetti, 1878, such as the oral plate structure and the position of the periproct, are herein described based on topo-typic material from the Middle Miocene of the Northern Apennines (Italy). Similar, well preserved specimens from the Early Miocene of Sardinia are attributed to Heterobrissus lubellii n.sp., which differs from H. montesi by its longer and wider petals and the peristome farther from the anterior margin of the test. The new available data confirm also that the genus Archaeopneustes Gregory, 1892 is junior synonym with Heterobrissus. Unreported specimens from the Late Oligocene of Alicante (Spain) enable to illustrate the plastron structure and other so far unknown features in Pygospatangus salvae Cotteau, 1890, the type species of the genus Pygospatangus Cotteau, 1890, and indicates that Pygospatangus is a junior synonym with Heterobrissus. Heterobrissus salvae differs from H. montesi mainly by its thicker shell and longer plates in the proximal part of the oral ambulacra I and V. The Recent species Heterobrissus niasicus (Döderlein, 1901), H. erinaceus Baker et Rowe, 1990 and H. gigas Baker et Rowe, 1990, from the Indo-Pacific, are herein transferred to Echinopneustes n. gen. Echinopneustes differs from Heterobrissus mainly by the labrum extending only to the adjoining ambulacral plate 2, not to plate 3 as in Heterobrissus, by the periproct being marginal, not inframarginal as in Heterobrissus, and bounded by the fifth plates in the interambulacrum 5, not by the fourth. The distribution of Heterobrissus, so far known from the Burdigalian of Sardinia, the Langhian of Northern Italy and the Serravallian of Cyprus, is extended to the Late Oligocene of Spain and to the Recent, with H. hystrix (Agassiz, 1880), today living in the Carribbean area. The functional morphology of the test, supported by actualistic comparison and by data taken from sedimentary settings and the associated taxa, indicates that Heterobrissus was an epibenthic feeder, preferring muddy outer shelf environments with tropical climate.