Profundulidae

Hernández-Ávila, Sonia Gabriela, Hoagstrom, Christopher W. & Matamoros, Wilfredo A., 2024, Historical biogeography of North American killifishes (Cyprinodontiformes) recapitulates geographical history in the Gulf of México watershed, Zoological Journal of the Linnean Society 202 (2) : -

Profundulidae

The major node within Profundulidae 30.7–14.2 Mya ( Fig. 3 , node 5) separates Profundulus Hubbs, 1924 from Tlaloc Álvarez and Carranza, 1951 . Tlaloc occurs across the Chiapas Massif and adjacent highlands within the Río Grijalva drainage ( Miller 1955, Cashner and Echelle 2020). The Upper Río Grijalva flows northwest until making an abrupt turn northeast, suggesting capture from a north-flowing river, possibly the ancestral Río Uxpanapa or Tonalá. This capture could have been caused by uplift of the northwestern Chiapas Massif 30–25 Mya ( Witt et al. 2012) or head-cutting of the lower Río Grijalva during a period of extensive erosion 35–25 Mya ( Abdullin et al. 2016) and potentially explains the distinctiveness of the Upper Grijalva fish community ( Elías et al. 2020). Divergence of Tlaloc from Profundulus , which probably arose in an ancestral Río Coatzacoalcos ( Fig. 8 ), provides an estimate for timing of this capture ( Table 2 ).

Notably, Profundulus is now largely restricted to Pacific slope drainages ( Domínguez-Cisneros et al. 2023). Presuming that Miocene, upland Profundulus no longer tolerated high-salinity or coastal environments, rising sea levels could explain the rarity of Profundulus on the Gulf slope, as proposed for Herichthys Baird & Girard, 1854 ( Pérez-Miranda et al. 2020). During the Middle Miocene Climatic Optimum (MMCO) 17.0–13.8 Mya ( Miller et al. 2020b), seas inundated broad areas north and east of the Sierra Madre del Sur and Chiapas Massif ( Blakey and Ranney 2018). Our chronogram indicates that diversification within Profundulus occurred thereafter ( Fig. 3 ), potentially from one refugial population.

Figures

Figure 3. Phylogenetic relationships and divergence times among taxa within North American killifish families Cubanichthyidae, Cyprinodontidae, Fundulidae, Goodeidae, and Profundulidae recovered by Bayesian inference with five concatenated loci (three mitochondrial and two nuclear) and 130 species.Red dots depict nodes with posterior probabilities <95%. Green arrows show fossil calibration points and brown arrows show secondary calibration points (Table 1). Numbered nodes are associated with environmental and geologic events in our biogeographical synthesis (Table 2).

Figure 8. Early–Middle Miocene diversification of North American killifishes in the Gulf of México region.Phylogenetic nodes (Fig.3) are indicated as N5–N7, N9–N11, and N14–N17, showing hypothetical separations between lineages (for details, see main text, Table 2, and Figs 6, 7). The Early Miocene Red River followed the Sabine route to an independent delta, potentially the estuary of origin for subgenus Fundulus, with subgenus Zygonectes arising in the Mississippi River estuary to the east (N15). The Red River joined the Mississippi River in the Middle Miocene.A Guadalupe River drainage emerged to the west in the Early–Middle Miocene, potentially the estuary of origin for the Fundulus similis species group, which diverged from subgenus Fundulus (N16). Widespread, sustained tectonism across southwestern North America isolated western tributaries from the Gulf of México, becoming endorheic drainages, some of which evidently harboured killifishes. Owing to a long history of tectonic activity, the details of these ancient endorheic drainages are unknown.Break-up of the Oligocene Río Grande drainage (Fig. 7) isolated Wileyichthys inland from Lucania (N14). Break-up of the Oligocene Madrean River drainage (Fig. 7) isolated Empetrichthyinae from Goodeinae (N6). Further break-up of the Madrean River separated Goodeinae from Characodontini-Illyodontini (N7). In the southern Gulf, capture of the upper Río Grijalva from an ancestral Río Coatzacoalcos isolated Profundulus from Tlaloc (N5). In the western Gulf, inland immigration of cyprinodontids resulted in peripheral isolates Cualac in the Río Pánuco (N9) and Megupsilon in the Late Miocene Río San Fernando (N11). The base map is a reconstruction for 20 Mya (Early Miocene, used with permission ©2023 Colorado Plateau Geosystems Inc.). The narrowed Gulf Trough follows Popenoe (1990) for Early Miocene.Later sea-level rise flooded the trough and isolated the Ocala High as an island. Two putative dispersal events are illustrated: N10, cyprinodontid eastward coastal immigration, founding Jordanella floridae on the Ocala High; and N17, Fundulus inland immigration up the Mississippi River, founding Fundulus sciadicus–Plancterus on the Northern High Plains.