Huracan schneideri (Sellards, 1916)

Jiangzuo, Qigao, Flynn, John J., Wang, Shiqi, Hou, Sukuan & Deng, Tao, 2023, New Fossil Giant Panda Relatives (Ailuropodinae, Ursidae): A Basal Lineage of Gigantic Mio-Pliocene Cursorial Carnivores, American Museum Novitates 2023 (3996), pp. 1-72 : 8-11

Huracan schneideri (Sellards, 1916)

Agriotherium schneideri: Sellards, 1916: 98 .

Hyaenarctos gregoryi: Frick, 1921 .

Hyaenarctos gregori: Frick, 1926: 74 .

Agriotherium schneideri: Stock, 1950: 2 .

Agriotherium schneider :- Miller et al., 1996: 570.

Agriotherium schneideri (in part): Hunt, 1998: 184.

TYPE SPECIMEN: USNM 8838 , mandible from Upper Bone Valley , Florida ( fig. 5 ) .

HYPODIGM: In addition to the holotype, the following specimens from Upper Bone Valley are also referred to this taxon— UF 18528 (isolated I1 or I2), UF 206887 , UF/FGS 3892 , UF 21227 (three M1s), UF 203158 , UF 133944 (two M2s), UF 47482 (p4), UF 17485 , UF 21226 (two m2s) .

EMENDED DIAGNOSIS: Large ailuropodine bear with distinct hypercarnivorous features. Mandible with premasseteric fossa always present; anterior premolars single rooted; P4 longer than M1, with variably subdivided hypocone; M2 anteroposteriorly short; p4 with weak anterior and posterior cingulid cusps and medial ridge; m1 with elongated paraconid, distinct metaconid, moderate mesoconid, and weak posterior entoconid.

DIFFERENTIAL DIAGNOSIS: Differs from Huracan coffeyi in H. schneideri by having smaller size, wider M2 with proportionally shorter talon, p4 with weaker anterior accessory cusp and stronger medial ridge, m1 with weaker mesoconid and smaller posterior entoconid, m2 with weaker and more posteriorly located metaconid and poorly subdivided entoconid; differs from Huracan qiui in H. schneideri by having distinctly shorter M1 and M2.

OCCURRENCE: Known from the latest Hemphillian NALMA (Hh4), from the Upper Bone Valley in Polk and Hillsborough Counties of Florida, the site of the holotype of “ A. ” schneideri (now the holotype specimen of the genotype species, Huracan schneideri ). At that time, species of Huracan occurred in North America in the southern part of the United States, and in Yepomera in Chihuahua and Rinconada in Guanajuato, both in Mexico ( Stock, 1950; Miller and Carranza-Castaóeda, 1996). A single lower m1 was found in Tehuichila in Hidalgo, Mexico, but it is of uncertain age ( Frick, 1926). Hyaenarctos gregoryi was erected based on several isolated teeth from the Mount Eden local fauna, California ( Frick, 1921), of Hh4 age ( Albright, 2000). These teeth are either broken or heavily worn, so their taxonomic assignment is unclear, but judging from the wide M1, these teeth could represent H. schneideri . A mandible that was recently found from Sedgwick County, Kansas also belongs to this species ( Everhart and Hawkins, 2020).

The absence of records in the more northern part of North America is probably biased by the paucity of fossil localities of similar age. Blancan records, consisting of a single M2 from the early Blancan Ringold Formation in Washington ( Martin, 2013) and a broken mandible from the Middle Blancan Glenns Ferry Formation that produces the Hagerman local fauna in Idaho ( Samuels et al., 2009), are insufficient to definitively diagnose the specimens to species, and thus are here regarded as Huracan cf. H. schneideri .

DESCRIPTION: New material of H. schneideri from the type locality of Upper Bone Valley, Florida is mainly represented by several isolated teeth. Nevertheless, these teeth show stable differences relative to those of Huracan coffeyi from Hh3.

Upper dentition: A single upper incisor (UF 18528) represents I1 or I2. The medial ridge is subdivided. A lateral ridge of the main cusp is slightly subdivided.

Three isolated M1s are added to the hypodigm for this species. UF 206887 ( fig. 6 : E5) is square in shape. M1 width across the metacone is significantly wider than that across the paracone. The most striking character of M1 is its strongly concave anterior border. The parastyle and metastyle are probably absent (but cannot be determined with certainty due to wear). The protocone is subdivided. UF/FGS 3892 and UF 21227 ( fig. 6 : E3) are similar in morphology and degree of wear. Both of these teeth are more heavily worn than is UF 206887. The width across the metacone is only slightly wider than that across the paracone. The concavities in the anterior and buccal borders of UF/FGS 3892 and UF 21227 are weaker than in UF 206887.

Two M2s are preserved. UF 203158 ( fig. 6 : E4) is large and wide. The talon is nearly absent, the buccal cingulum is weak, and there is a small transverse ridge between the paracone and protocone. UF 133944 ( fig. 6 : E2) represents a much smaller M 2 in a maxillary fragment. The talon is stronger in this tooth than in UF 203158, its lingual border is rounded, and the metaconule is not distinguishable from the protocone.

Lower dentition: The p4 UF 47482 ( fig. 7 : A2) has a triangular occlusal shape. A buccal concavity is present. The anterior accessory cusp is present but weak, whereas the posterior accessory cusp is well developed. A distinct medial ridge is present on the lingual side of the main cusp. The m1 is robust. A cingulid is only present on the buccal and lingual sides of the paraconid of m1. A strong buccal concavity is present between the trigonid and talonid, whereas only weak lingual concavities are present between the paraconid and protoconid and between the protoconid and metaconid. The mesoconid is present, but not well distinct. At the posterolingual side of the tooth, there are three cusps, representing the metaconid and a subdivided entoconid. The posterior entoconid is distinctly smaller than the anterior one. Two m2s are known. UF 17485 (m2 cast) also is robust. Its metaconid is located slightly posterior to the protoconid, and on its talonid the entoconid is small and not subdivided. UF 21226 ( fig. 7 : A4) is unusual in having a more posteriorly located and much weaker metaconid, and its entoconid also is very small and not subdivided.

Figures

FIG. 5. Holotype specimen of Huracan schneideri, USNM 8838, in A. lateral; B. medial; and C. dorsal views.

FIG. 6. Upper P4–M2 of Huracan and related taxa. A. Huracan qiui, HMV 2005, Wangjiashan. B. Huracan coffeyi, B1. AMNH F:AM 76006 (reversed), Quiburis Formation; B2. AMNH F:AM 145923 (reversed), Quiburis Formation; B3. AMNH F:AM 49372, Big Sandy Formation. C. Huracan roblesi (IVPP uncatalogued cast), Venta del Moro. D. Agriotherium africanum, Langebaanweg, D1. AMNH FM 105141 (cast of PQ-L 47137, reversed); D2. AMNH FM 105141 (cast of PQ-L 41404, reversed). E. Huracan schneideri, E1. IGM 6668 (cast), Rancho Viejo Beds; E2. UF 133944 (reversed); E3. UF 21227 (reversed); E4. UF 203158 (reversed); E5. UF 206887 (reversed), not all associated. F. Indarctos atticus, F1. IVPP FV 2107 (cast), Samos; F2. IVPP V 6893.10–12, Lufeng. G. Plithocyon teilhardi, AMNH FM 26594, Tunggur Formation. Each letter represents one species and each number represents one individual.

FIG. 7. Lower p4–m2 or m3 of Huracan and related taxa. A. Huracan schneideri: A1. IGM 6413 (cast), Rancho Viejo Beds; A2. UF 47482, Upper Bone Valley; A3. UF 53977, Upper Bone Valley; A4. UF 21226 (reversed), Upper Bone Valley, not all associated. B. Huracan coffeyi: B1. AMNH F:AM 146483; B2. AMNH F:AM 76013; B3. AMNH F:AM 146493; B4. AMNH F:AM 76023; B5. AMNH F:AM 146571; B6. AMNH F:AM 146488 (reversed); B7. AMNH F:AM 76021 (reversed); B8. AMNH F:AM 146481 (reversed); B9. AMNH F:AM 146490; B10. AMNH F:AM 76033 (reversed); B11. AMNH F:AM 146500; B12. AMNH F:AM 76031, not all associated. C. Indarctos cf. I. atticus: AMNH F:AM 22332, Baode. D. Agriotherium hendeyi: AMNH F:AM 76000, Quiburis Formation. E. Agriotherium africanum, Langebaanweg: E1. AMNH FM 105140 (cast of PQ-L45114, reversed); E2. AMNH FM 105148 (cast of PQ-L 50006); E3. AMNH FM 105149 (cast of PQ-L50007, reversed); E4. PQ-L 50446 (reversed); E5. PQ-L 50004, all not associated. F. Agriotherium palaeindicum: IVPP V 18411 (reversed), Xiaoxian. G. Plithocyon teilhardi: AMNH FM 26594, Tunggur Formation. Each letter represents one species and each number represents one individual.