Proparrella pusilla, 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 : 47-48

publication ID	https://doi.org/10.1186/s13358-023-00302-5
persistent identifier	https://treatment.plazi.org/id/492D87AA-FF85-FFCB-0236-FED0608EFE18
treatment provided by	Felipe
scientific name	Proparrella pusilla
status	sp. nov.

Treatment

Proparrella pusilla n. sp.

Figure 23q–r View Fig

Holotype NMB P15578 View Materials ( Fig. 23r View Fig ), Tortonian , Gatun FM, Atlantic Panama, PPP 2168 .

Paratypes 4 specimens: 3 specimens same data as holotype ( NMB P15579-81 View Materials ) ; 1 specimen, Messinian , Chucunaque FM , Pacific Panama, Darien, PPP 1576 ( NMB P15582 View Materials ) .

Referred specimens 5 specimens Messinian, Chucunaque FM , Pacific Panama, Darien , 2 specimens PPP 1576 , 3 specimens PPP 1578 .

Etymology From pusillus (Latin) = teeny, small, referring to the small size of the specimens of this species.

Diagnosis OL:OH = 1.03–1.08. Maximal size 1.4 mm. Otolith shape nearly quadratic with similarly high and projecting predorsal angle and postdorsal projection. Dorsal rim relatively low with weak concavity behind postdorsal angle. Sulcus long, narrow, with low ostial lobe and long, narrow, straight cauda; OL:SuL = 1.75–2.0; sulcus inclination angle 12–14°. Subcaudal iugum moderately long, narrow. Dorsal depression indistinct. Ventral furrow distinct, close to ventral rim of otolith.

Description Otolith size up to 1.4 mm in length (holotype). OH:OT = 2.7–2.9. Dorsal rim anteriorly straight, posteriorly slightly concave, with broadly rounded, nearly centrally positioned postdorsal angle. Predorsal angle projecting, high, at about the level and strength of postdorsal projection resulting in nearly symmetrical otolith outline. Preventral and postventral angles rounded, slightly recessed. Ventral rim straight, horizontal. Anterior and posterior rims nearly straight, slightly inclined downward. All rims smooth.

Inner face nearly flat. Sulcus sole-shaped, relatively deep, inclined at 12–14°; ostium moderately wide with moderate ostial lobe; cauda long, narrow, straight. OL:SuL = 1.75–2.0. Subcaudal iugum moderately long, narrow, sometimes rather indistinct. Dorsal depression shallow, indistinct. Ventral furrow distinct, regularly curved and relatively close to ventral rim of otolith. Outer face broadly convex, smooth.

Discussion Despite of its small size, the otoliths of P. pusilla are relatively constant in expression and are therefore believed to represent a small species rather than juvenile specimens. Te highly distinctive otolith outline and the relatively short sulcus distinguish it from its parallel occurring congener, P. darienensis .