Journal of Paleontology, 92(5), 2018, p. 804–837 Copyright © 2018, The Paleontological Society 0022-3360/18/0088-0906 doi: 10.1017/jpa.2017.153
Diversity and preserved shell coloration patterns of Miocene Conidae (Neogastropoda) from an exposure of the Gatun Formation, Colón Province, Panama
Jonathan R. Hendricks1,2,3
1Paleontological Research Institution, 1259 Trumansburg Road, Ithaca, New York, USA ⟨
jrh42@cornell.edu⟩ 2Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, New York, USA 3Department of Geological Sciences, Ohio University, Athens, Ohio, USA
Abstract.—Extant members of the neogastropod family Conidae (cone snails) are renowned for their often dazzling shell coloration patterns and venomous feeding habits. Many cone snail species have also been described from the fossil record, but to date have been little used to understand the evolutionary history of extant clades. The cone snail fauna of the Miocene Gatun Formation of Colón Province, Panama is especially important for understanding the temporal and biogeographic history of tropical American Conidae. Intensive, focused collecting from an exposure of the lower Gatun Formation (deposited ca. 11–10 Ma) resulted in the discovery of nearly 900 specimens of Conidae. Remarkably, many of these well-preserved specimens exhibit revealed coloration patterns when exposed to ultraviolet light. The fluorescing coloration patterns were used in conjunction with other features of shell morphology to differentiate species and, in most cases, evaluate their potential relationships to members of the extant tropical American fauna. Nine species are fully described from this locality, one of which is recognized as new: Conus (Stephanoconus) woodringi n. sp. At least one, and perhaps more, additional Conidae species are also present at the study locality. The diversity of this Conidae fauna is considered moderate relative to other recently analyzed tropical American fossil assemblages. The phylogenetic diversity of the assemblage, however, is noteworthy: six of the ten species can be confidently assigned to six different clades of extant Conidae, providing potentially useful calibration points for future phylogenetic studies.
http://zoobank.org/8fe00c31-8f3f-4514-85af-29068e468cd3
Introduction
The colorful and intricately patterned shells of cone snails (Fig. 1), which comprise the neogastropod family Conidae, have attracted the interest of naturalists and collectors for centuries. Besides having shells that are beautiful natural objects, cone snails are highly specialized venomous predators of worms, mollusks, or fish (e.g., Kohn, 1956; Duda et al., 2001; Olivera et al., 2014), and are ecologically important in tropical and subtropical marine habitats (e.g., Kohn 1959, 2001). The complex venoms (conopeptides) that they use to paralyze their prey are noteworthy for sometimes being dangerous to people (see Kohn, 2016), though they also hold significant pharmacological potential for treating varied human ailments (e.g., Vetter and Lewis, 2012;Gorson andHolford, 2016). Finally,with nearly 900 extant species (see below), cone snails are remarkably diverse and their relationships to each other are becoming better understood. Based on the branching topology of a newmolecular phylogenetic hypothesis for cone snails (Puillandre et al., 2014), Puillandre et al. (2015) divided extantmembers of the family into four genera: (1) the basal genus Profundiconus Kuroda, 1956, represented by 28 species (Marshall and Bouchet, 2016); (2) Californiconus
Tucker and Tenorio, 2009, represented by one living eastern Pacific species (Bouchet, 2011); (3) Conasprella Thiele, 1929, represented by 113 species (Marshall and Bouchet, 2017); and (4) the hyperdiverse genus Conus Linnaeus, 1758, represented by 755 species (Bouchet and Gofas, 2015). Puillandre et al. (2015) further divided Conasprella and Conus into subgenera corre- sponding with individual subclades; many of these subgenera correspond with genus-level rankings proposed earlier by Tucker and Tenorio (2009). Uribe et al. (2017) very recently published a phylogenetic analysis of mitochondrial genomic data and recognized two additional genus-level clades within the Conidae: Lilliconus Raybaudi Massilia, 1994 and Pseudolilliconus Tucker and Tenorio, 2009. Cone snails have a fossil record that extends back to the
early Eocene (Kohn, 1990; Röckel et al., 1995; Hendricks and Portell, 2008), and their shells are common constituents of many Miocene, Pliocene, and Pleistocene marine fossil deposits, especially in tropical America. Several of these cone snail faunas have received recent attention by paleontologists, including those of the Miocene (Landau et al., 2016) and early Pliocene (Landau and da Silva, 2010) of Venezuela, the late Miocene and early Pliocene of the Dominican Republic
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