The Demosponge genus Leptomitus and a new species from the Middle Cambrian of Spain

Palaeontology (Impact Factor: 2.24). 02/2007; 50(2):467 - 478. DOI: 10.1111/j.1475-4983.2007.00635.x


Forty-five specimens of Leptomitus conicus sp. nov. have been collected from the base of the Murero Formation (Caesaraugustan, Middle Cambrian) in the Murero area of Zaragoza, north-east Spain. The new species is a small obconical sponge, which has coarse oxeas forming parallel rods that run the whole length of the specimens in the manner typical of the genus. The biostratigraphy and facies of the levels with Leptomitus conicus have been analysed. Palaeoecological information derived from associated trilobites, brachiopods and ichnofossils shows that L. conicus lived in a soft substrate of a sublittoral environment of low to low/moderate energy. According to established Cambrian palaeogeographical reconstructions, a tropical distribution is inferred for the genus Leptomitus. Based on body shape, wall structure and stratigraphical distribution, a phylogenetic tree of the various Leptomitus species is proposed, with a central stock of simple cylindrical sponges branching out to other morphs.

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    • "The eocrinoids from this locality were found in a thin level associated with the trilobites Eccaparadoxides asturia− nus (Sdzuy, 1968), Badulesia granieri (Thoral, 1935), Cono− coryphe (Parabailiella) languedocensis Thoral, 1946 and Condylopyge sp. The presence of both agnostoid and poli− meroid trilobites suggests open marine conditions; however, the sponge Leptomitus conicus is also present, which is typi− cal of soft substrates in low or moderately low energy condi− tions (García−Bellido et al. 2007). "
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    ABSTRACT: E. 2009. Middle Cambrian gogiid echinoderms from Northeast Spain: Taxonomy, palaeo− ecology, and palaeogeographic implications. Acta Palaeontologica Polonica 54 (2): 253–265. DOI: 10.4202/app.2008.0010 Gogia parsleyi Zamora sp. nov. and Gogia sp. are described from two different echinoderm assemblages, both from the middle Cambrian of the Murero Formation (Iberian Chains, NE Spain). Gogia parsleyi is reconstructed and described on the basis of fifteen complete or partial specimens and numerous isolated plates. It is characterised by spiralled brachioles, simple epispires, sometimes covered by stereomic domes or tiny cover plates, and by thecal plates arranged in subregular circlets. This gogiid population comprises juveniles, advanced juveniles and mature individuals. The material was found in the upper part of the Murero Formation (upper Caesaraugustian–lower Languedocian). Gogia sp. is represented by two almost complete specimens and several isolated plates from the lower part of the Murero Formation (lower Caesar− augustian). The genus Gogia was first described in Western Gondwana from the Languedocian (upper middle Cambrian) of France, but the material from Spain is older and represents the oldest record of this genus in Gondwana, suggesting an early migration from Laurentia. The gogiids are well preserved in two echinoderm Lagerstätten, which, together with other echinoderms, comprise the majority of the fossil fauna. Both levels are derived from obrution deposits produced in calm and open marine conditions, sometimes affected by sporadic storms. Their holdfast morphology suggests that these gogiids were low−tier suspension feeders, living attached to trilobite fragments in a soft, muddy environment.
    Acta Palaeontologica Polonica 06/2009; 54(2). DOI:10.4202/app.2008.0010 · 1.87 Impact Factor
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    ABSTRACT: Phacopid trilobites are among the most ubiquitous fossils within the Lower and Middle Devonian strata of Morocco, and display a diversity of form seen at no other point in the history of the family. The southern and southeastern margins of Morocco are ideal for studying the Phacopidae through this time interval, because rock units of this age are present in long, continuous exposures that are traceable for many kilometers along strike, only affected by low amplitude folding and minor faulting. Furthermore, the fossils themselves show articulation and preservation matched in few other localities (making complete, definitive descriptions possible), and are commercially mined by the local Berbers (making specimens available in large numbers). This study is of the phacopids, as they occur in correlatable strata from the three major Devonian basins in southern Morocco (the Tindouf, Tafilalt, and Ma'der basins), and shows that their presence is useful for correlation within and between these basins, as well as farther abroad. In the process, 11 new taxa of specific or subspecific rank are described, including a single new species of Reedops, a single new species of Boeckops, and 6 new species/subspecies of Phacops. (Three additional Phacops species from this region have been described recently in Chatterton et al., 2006, including Phacops smoothops, P. granulops, and P. lebesus). New information is also provided for Reedops bronni (Barrande, 1846), R. cephalotes hamlagdadianus Alberti, 1983, Pedinopariops (Hypsipariops) vagabundus Struve, 1990, Drotops megalomanicus megalomanicus Struve, 1990, and D. armatus Struve, 1995. Cladistic analysis of these taxa and other pertinent phacopids suggests the relationships of these taxa, and has implications for their higher-level taxonomic placement. The in-depth study of large numbers of Reedops and Phacops specimens, in a wide range of depositional settings, has also led to some insights into their life-modes, enrollment behaviours, sculpture, and coaptative devices.
    Geological Society of America Abstracts with Programs; 01/2006
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