Ariosoma mesohellenica, Agiadi & Koskeridou & Thivaiou, 2021

Agiadi, Konstantina, Koskeridou, Efterpi & Thivaiou, Danae, 2021, At the crossroads: early Miocene marine fishes of the proto-Mediterranean Sea, Fossil Record 24 (2), pp. 233-246 : 234

Ariosoma mesohellenica sp. nov.

urn:lsid:zoobank.org:act:4B603ED2-93BE-429E-

B4EC-8D5F45A9C24C registered on 21/7/2021

Fig. 3A–D

2004 Ariosoma balearicum (Delaroche, 1809) – Hoedemakers & Batllori, pl. 1, figs. 8–14.

Holotype

Figure 3A , AMPG ( V) 2361, Aquitanian, Felli section, level 11, Grevena Prefecture, Greece; OL, 3.40; OH, 2.80; CL, 2.49 mm; α, 4 ◦.

Paratypes

Two specimens, AMPG ( V) 2362–3, same data as holotype ; one specimen, AMPG ( V) 2364, Aquitanian , Felli section, level 12, Grevena Prefecture, Greece .

Etymology

After the MHB, where the type section sediments were deposited.

Diagnosis

Elongated otoliths with OL/OH of 1.16–1.26. The sulcus extends almost to the distal edge, with CL/OL of 0.58–0.74, and α between 2 and 6 ◦.

Description

Elongated, thick spindle-shaped otoliths with an elongated central sulcus that opens toward the dorsal rim through an intricate ostial channel. The ostial channel is placed almost at the proximal edge of the sulcus and is perpendicular to it. The dorsal depression is well expressed. The dorsal rim is curved in the distal part.

Distribution

Aquitanian of the western proto-Mediterranean and the MHB.

Remarks

These otoliths have a more elongated sulcus than Ariosoma balearicum otoliths, which almost reaches the posterior edge ( Fig. 3E–F ; Agiadi and Albano, 2020). Moreover, the dorsal extension is located more frontally, as it is in Ariosoma moravica (Sulc 1932) ( Nolf, 2013) . The otoliths assigned to A. balearicum from the lower–middle Miocene of Catalonia by Hoedemakers and Batllori (2005) also show a frontal positioning of the dorsal extension. In contrast through to A. moravica , the sulcus is more elongated, indicating that these specimens also should be placed in Ariosoma mesohellenica sp. nov. Furthermore, the specimens assigned to Ariosoma aff. balearicum by Steurbaut (1984) should not be placed within this species because their sulcus is much shorter and does not extend close to the distal rim. Similarly, the otoliths assigned by the same authors to Ariosoma globosum Steurbaut, 1984 are distinguished from those of A. mesohellenica because their sulcus does not extend toward the distal rim and their shape is pointed.

Figures

Figure 3. Photographs of the identified otoliths from the Felli section. (A–D) Ariosoma mesohellenica sp. nov.: (A) holotype, AMPG(V) 2361, inner face and dorsal view; Felli 11; (B) paratype, AMPG(V) 2364, Felli 12; (C–D) paratypes, 2362 and 2363, Felli 11. (E–F) Ariosoma balearicum (Delaroche), Holocene, Israel. (G–H) Gnathophis elongatus sp. nov., Felli 11: (G) holotype, AMPG(V) 2365, inner face and ventral view; (H–J) paratypes, AMPG(V) 2366–2368. (K–L) Gnathophis saubriguensis (Steurbaut): (K) Felli 11, (L) Felli 12; (M– O) Spicara cf. gossei: (M) inner face and ventral view; Felli 11, (N–O) Felli 12. (C), (H), (K), (L), and (M) have been mirrored to facilitate comparison.