Makaira teretirostris Rutimeyer, 1857

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 : 19-20

† Makaira teretirostris Rutimeyer, 1857

( Fig. 11 A)

1857 † Encheiziphius teretirostris Rutimeyer : 561, pl. i.

1871 † Brachyrhynchus teretirostris Rutimeyer ; Van Beneden: 495, pl. i – ii, figs 1, 2.

Emended diagnosis. This species is characterized by the following single autapomorphic character: rostrum cylindrical (or round in cross–section) with equal height and width at 0.5 L, giving it a characteristic conical aspect.

Holotype. Specimen is currently missing, and the exact point of collection is unknown; it is represented by a 520 mm nearly complete rostrum ( Van Beneden 1871, pl. 1).

Occurrence. Pliocene sandstones, Montpellier, France ( Roman 1922). Early Pliocene Zanclean, Sables ̀a Gryphaea virleti Formation ( Bianucci et al. 2008).

Remarks. The description here is based on a natural scale drawing of a nearly complete rostrum in ventral view accompanied by seven schematic drawings of cross-sections ( Fig. 12A) provided by Van Beneden (1871). In cross-section, the rostrum is nearly circular at 0.5 L and gradually tapers towards its distal end ( Fig. 12A). The distal tip is almost circular basally, becomes oval in the middle part and ends in a rounded point ( Fig. 12A). The distal tip has a globular shape, while the transverse outlines at 0.5 L and 0.25 L indicate a cylindrical rostrum in cross-section ( Fig. 12A; Supplemental file 1). The rostrum has two continuous, oval, small internal canals that are centrally aligned ( Fig. 12A). The H1 variable suggests large, whereas the CA1/AR1 ratio suggest small canals ( Table 3 ). In ventral view, there is a pronounced canal that is visible from the most proximal part of the rostrum to about half the distance of the specimen ( Fig. 12a). The measurements of † M. teretirostris , which were published by Van Beneden based on a cast ( L = 522 mm, W1 = 52 mm), differ from those of the natural size illustration ( Fig. 12A). The measurements taken from the original illustration are the same as those published by Rutimeyer (1857): L = 530 mm, W1 = 58 mm, D1 = 50 at the proximal end. By converting these measurements in ratios, five out of the six ratios of † M. teretirostris are in the range of the extant M. nigricans (see supplemental file 1 for unconverted values). The ratio D1/W1 is the only value that differs from those of M. nigricans as shown in the PCA, where † M. teretirostris falls outside of extant species representing an outlier ( Fig. 10A) and seemingly is unrelated to any extant species ( Fig. 10B). The ratio D1/ W1 = 0.88 indicates that the rostrum is rounder than oval at its base and represents the biggest value observed for these ratios in all studied specimens (Supplemental material 1).