Makaira fierstini, Gracia & Correa-Metrio & Carvalho & Velez-Juarbe & P̆rik & & Kri, 2022

Gracia, Carlos De, Correa-Metrio, Alex, Carvalho, Monica, Velez-Juarbe, Jorge, P ̆ rik, Tom ́ a ̆ s, , Carlos Jarami & Kri, nd Jurgen, 2022, Towards a unifying systematic scheme of fossil and living billfishes (Teleostei, Istiophoridae), Journal of Systematic Palaeontology (2091959) 20 (1), pp. 1-36 : 14-15

† Makaira fierstini sp. nov.

( Figs 5D–F, 6)

Diagnosis. † Makaira fierstini sp. nov. is characterized by the following autapomorphy (autapomorphic characters indicated by an asterisk): in lateral view, lateral planes are present at the level of the triangular process of the premaxillaries that extend up to half of its total height$. Makaira fierstini sp. nov. can also be differentiated by the following combination of characters: the rostrum is straight along its entire length; prenasals never contact each other in dorsal view; denticles cover the entire lateral and ventral surfaces; large internal canals present.

Derivation of name. Named in honour of the late Harry Fierstine (1932–2021) in recognition of his contributions to our understanding of the fossil record of marlins and billfishes.

Holotype. USNM 358534, a nearly complete rostrum, 794 mm long.

Occurrence. Late Miocene (12.0–9.2 Ma), lower Gatun Formation ( Collins et al. 1996; Hendy 2013). Sabanitas, Colon, Panama at 43 ǫ 38 Ɩ 19.39 ʺ N + 675 m, 116 ǫ 14 Ɩ 28.86 ʺ W + 1600 m, ( Fierstine 1999a). The type locality is not accessible anymore, as it is currently a housing development.

Remarks. The rostrum of † Makaira fierstini sp. nov. ( USNM 358534) is almost complete. The premaxillaries and prenasals are well preserved, whereas the nasals are poorly preserved ( Fig. 5D–F). The estimated total length is 794 mm, of which 45 mm of the distal tip, however, are missing ( Fierstine 1999a). The rostrum is slender and has an oval outline in cross-section at 0.5 L and 0.25 L distances ( Fig. 7G). In dorsal view, the prenasals never contact each other or the premaxillaries ( Figs 5D, 7G). In lateral view, the rostrum is completely straight with no detectable distal curvature ( Fierstine 1999a). The premaxillaries are laterally planar at their proximal ends and occupy half of the total lateral height ( Fig. 5F). The rostral morphology indicate that the distal tip is slender and pointed (Supplemental material Fig. S1B). In ventral view, the premaxillaries begin to be separated at 483 mm from their distal tips ( VSPM) ( Fig. 5E). The nasals are only partially preserved ( Fig. 5D, E). The internal canals are in a medial position, centrally aligned and have oval cross-sections ( Fierstine 1999a). † Makaira fierstini sp. nov. has proportionally large internal canals (Table 4). The statistical analysis ( Fig. 10) indicates that the rostrum morphology of † M. fierstini sp. nov. is close in morphology to M. nigricans and Is. indica ( Fig. 10), but it differs from them in its extremely long rostrum, shorter narial aperture, the possession of large internal canals ( Table 3 ) and by having planar premaxillaries that occupy half of the lateral height in its proximal part ( Figs 5D–F, 7G).