Bollmannia propensa, Schwarzhans & Aguilera, 2024

Schwarzhans, Werner W. & Aguilera, Orangel A., 2024, Otoliths of the Gobiidae from the Neogene of tropical America, Swiss Journal of Palaeontology (13) 143 (1), pp. 1-129 : 34-35

publication ID	https://doi.org/10.1186/s13358-023-00302-5
persistent identifier	https://treatment.plazi.org/id/492D87AA-FF8A-FFC6-0236-FF506782FE78
treatment provided by	Felipe
scientific name	Bollmannia propensa
status	sp. nov.

Treatment

Bollmannia propensa n. sp.

Figure 19a–e View Fig

Holotype NMB P15523 View Materials ( Fig. 19a View Fig ), Messinian , Onzole FM, Ecuador, PPP 3314 .

Paratypes 5 specimens: 1 specimen Tortonian, Pacific Panama, Darien, Yaviza FM PPP 1620 ( NMB P15527 View Materials ) ; 2 specimens Tortonian , Ecuador, Angostura FM , 1 specimen PPP 3480 ( NMB P15526 View Materials ) , 1 specimen PPP 3465 ( NMB P15528 View Materials ; 2 specimens same data as holotype ( NMB P15524-25 View Materials ).

Referred specimens 18 specimens: 3 specimens Tortonian, Pacific Panama, Yaviza FM , 1 specimen PPP 1620 , 2 specimens PPP 1566 ; 3 specimens Tortonian, Ecuador, Angostura FM , 1 specimen PPP 3439 , 2 specimens PPP 3465 ; 3 specimens Messinian, Ecuador, Onzole FM PPP 3314 ; 9 specimens Messinian, Pacific Panama, Darien, Chucunaque FM , 6 specimens PPP 1576 , 3 specimens PPP 1578 .

Etymology From propensus (Latin) = inclined, skewed, referring to the parallelogram-like shape of the otolith.

Diagnosis OL:OH = 1.2–1.3. Maximal size 4.6 mm (holotype). Predorsal rim rounded or depressed; postdorsal region slightly elevated. Preventral projection and postdorsal projection strong giving otolith a parallelogram-like shape. Dorsal rim irregularly undulating or slightly crenulated. Sulcus large; OL:SuL = 1.65–1.85. Subcaudal iugum long, wide.

Description Otolith size up to 4.6 mm in length (holotype). OH:OT = 3.1–3.4 (one specimen of Fig. 19d View Fig OH:OT = 2.7). Predorsal angle low, slanted or depressed, postdorsal angle slightly expanded. Postdorsal projection projecting well beyond postventral angle, slightly bent outward; preventral angle distinctly projecting; both resulting in parallelogram-like otolith shape. Ventral rim straight, horizontal. Anterior rim inclined, posterior rim inclined, with variable, broad and shallow or no indentation at its middle. Ventral rim smooth, dorsal rim irregularly undulating or slightly crenulated.

Inner face flat in vertical direction and distinctly bent in horizontal direction. Sulcus sole-shaped with moderate ostial lobe and narrow cauda, moderately deepened, inclined at 12–15°. Caudal tip rounded, slightly bent upward. OL:SuL= 1.65–1.85. Subcaudal iugum long, wide. Dorsal depression wide, rather indistinct and close to sulcus with moderately developed crista superior. Ventral furrow distinct, relatively distant from ventral rim of otolith. Outer face nearly flat with moderate subcentral umbo (only one specimen with strongly convex outer face— Fig. 19d View Fig ), few radial furrows on dorsal field close to otolith margin.

Discussion Bollmannia propensa is easily recognized by its parallelogram-like shape, thin appearance and distinctly bent inner face in horizontal direction. It appears to be restricted to the late Miocene of the East Pacific. It resembles most the extant B. umbrosa ( Fig. 19f View Fig ) but differs in the more slender shape (OL:OH = 1.2–1.3 vs 1.1– 1.15) and the distinctly expanded postdorsal projection.