Adeonella adae ( Neviani, 1891 )
publication ID |
https://doi.org/ 10.1080/00222931003760061 |
persistent identifier |
https://treatment.plazi.org/id/FB2D9A7D-A45E-EE34-FE57-FB98795FAEF7 |
treatment provided by |
Felipe |
scientific name |
Adeonella adae ( Neviani, 1891 ) |
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Adeonella adae ( Neviani, 1891) View in CoL
( Figures 3C View Figure 3 , 8 View Figure 8 )
Smittia Adae Neviani, 1891: 127 View in CoL , pl. 4, fig. 7
Microporella (Diporula) Adae (Smittia) : Neviani, 1896a: 118; 1896b: 25, fig. 8; 1900a: 364; 1900b: 181, pl. 2, fig. 8.
Adeonella polystomella: Rosso, 1989b: 178 View in CoL , pl. 2, figs. 1,2.
Examined material
Early Pleistocene: Monte dell’Apa (central Sicily): five fragments from sample 2b, C concretions on shelf soft-bottoms. PMC. R.I.Ps.B6a; Furnari Unit in the Barcellona Pozzo di Gotto Basin (north-east Sicily), presumably deposited in mid-to-deep circalittoral environments: a total of five fragments from samples MCE 4 and MCE 134. PMC. R.I.Ps.B6b.
Description
Branches ribbon-like, 2 mm wide with nine or ten zooidal rows on each side; wider (3 mm and about 15 zooidal rows) proximally to bifurcations. Autozooids usually elongate hexagonal to rhomboidal ( Figure 8B–E View Figure 8 ), with a rounded distal portion and a narrow, proximal termination; marginal rows consisting of larger subrectangular zooids. Frontal shield finely granular and flat but intumescent in the best-preserved specimens, pierced by large pores, the peripheral ones often elongated and aligned along a row. Primary orifice with a narrow sinus sometimes visible through the spiramen ( Figure 8D View Figure 8 ). Secondary orifice semicircular to transversely elliptical, rarely with a blunt proximal process. Spiramen orbicular but variable in size; separated from the secondary orifice by a stout bridge, usually flanked by two pores ( Figure 8D View Figure 8 ). A single, small peristomial avicularium presumably present on a few zooids situated just distolaterally to the spiramen and proximally directed. A large frontal avicularium is usually present in the proximal third of each zooid, except for the marginal rows, the rostrum blunt triangular, rarely somewhat spathulate ( Figures 8C,F View Figure 8 ), distally or distolaterally directed. Smaller round-to-triangular, variably oriented frontal avicularia, usually located at the lateral and/or proximal angles in the markedly diamond-shaped zooids, seem to develop on senescent zooids, whose orifices are becoming occluded by calcification ( Figure 8E,F View Figure 8 ). Vicarious avicularia and gonozooids seemingly absent.
Measurements
ZL: 571 ± 31.11, 500–625 (2, 17); ZW: 370 ± 52.77, 294–469 (2, 17); sOL: 69 ± 9.23, 56–82, (2, 14); sOW: 115 ± 6.73, 106–128 (2,14); fAL: 121 ± 16.94, 88–147 (2, 13); fAW: 84 ± 9.01, 77–100 (2, 6).
Remarks
Although examination of Neviani’s type material was hampered, Adeonella adae features are well depicted in fig. 8 by Neviani (1891), reproduced on Figure 8A View Figure 8 . The species is well characterized by the presence of its proximally located and distally directed frontal avicularium. This feature is unique within the Mediterranean species, and is reminiscent only of the Recent A. gibba Hayward and Cook, 1983 from South Africa. Nevertheless, in this latter species, which differs also in several other characters, the proximal avicularium is located distally to the spiramen. A relatively long frontal avicularium has been figured also for some specimens ascribed to A. polystomella from Messinian layers cored in the Gulf of Gabes by Moissette (1997: pl. 3, fig. 3) but, although variably inclined, it is always proximally directed.
Distribution
Adeonella adae View in CoL seems to be restricted to the Pleistocene of Italy. It is known from northern localities, in the “clays” cropping out near Livorno (Tuscany: Neviani 1891; 1896 a, 1900a), and from some southern sites, including Spilinga ( Neviani 1896b; 1900b) in Calabria, and Furnari (near Messina: Messina 2003; Di Geronimo et al. 2005) and Gela ( Rosso, 1989b), in Sicily. Specimens are always rare and originate from sandy sediments, carbonate to silici-bioclastic in composition, which were presumably deposited in shallow circalittoral environments.
R |
Departamento de Geologia, Universidad de Chile |
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Genus |
Adeonella adae ( Neviani, 1891 )
Rosso, Antonietta & Novosel, Maja 2010 |
Adeonella polystomella: Rosso, 1989b: 178
Rosso A 1989: 178 |
Microporella (Diporula)
Neviani A 1896: 118 |
Neviani A 1896: 25 |
Smittia Adae Neviani, 1891: 127
Neviani A 1891: 127 |