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Leptophoca proxima
Taxonomy
Prophoca proxima was named by Van Beneden (1876) [No type specimen number listed by Van Beneden (1876). Koretsky (2001) lists the lectotype. IRSN = Institute Royal des Sciences Naturelles de Belgique, Brussels, Belgium]. Its type specimen is IRSN 1146 Ct. M 279, a limb element (humerus), and it is a 3D body fossil. Its type locality is Vieux-Dieu, which is in a Langhian/Serravallian open shallow subtidal sandstone in the Berchem Formation of Belgium.
It was recombined as Leptophoca proxima by Ray (1976), Dewaele et al. (2017), Berta et al. (2018), Kienle and Berta (2019), Berta et al. (2022), Rule and Park (2024).
It was recombined as Leptophoca proxima by Ray (1976), Dewaele et al. (2017), Berta et al. (2018), Kienle and Berta (2019), Berta et al. (2022), Rule and Park (2024).
Synonyms
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Synonymy list
| Year | Name and author |
|---|---|
| 1874 | Prophoca proxima Vanden Broeck p. 199 |
| 1876 | Prophoca proxima Van Beneden p. 802 |
| 1898 | Prophoca proxima Trouessart p. 382 |
| 1904 | Prophoca proxima Trouessart p. 285 |
| 1906 | Leptophoca lenis True p. 836 figs. Plate LXXV |
| 1922 | Prophoca proxima Kellogg p. 116 |
| 1922 | Leptophoca lenis Kellogg p. 123 |
| 1930 | Leptophoca lenis Hay p. 562 |
| 1947 | Monatherium (Leptophoca) lenis Friant p. 6 |
| 1947 | Prophoca proxima Friant p. 7 |
| 1976 | Leptophoca proxima Ray p. 394 |
| 2001 | Prophoca proxima Koretsky p. 61 |
| 2001 | Leptophoca lenis Koretsky p. 62 |
| 2003 | Leptophoca lenis Deméré et al. p. 49 figs. Fig. 3.3 |
| 2008 | Leptophoca lenis Koretsky and Barnes p. 547 |
| 2012 | Leptophoca lenis Koretsky et al. p. 5 |
| 2017 | Leptophoca proxima Dewaele et al. p. 25 |
| 2018 | Leptophoca proxima Berta et al. p. 210 figs. Fig. 2 |
| 2019 | Leptophoca proxima Kienle and Berta |
| 2022 | Leptophoca proxima Berta et al. p. 7 figs. Table 1.1 |
| 2023 | Leptophoca lenis Hafed et al. |
| 2024 | Leptophoca proxima Rule and Park p. 10 figs. Table 2 |
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If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.
†Leptophoca proxima Van Beneden 1876
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Invalid names: Leptophoca lenis True 1906 [synonym]
Diagnosis
| Reference | Diagnosis | |
|---|---|---|
| I. A. Koretsky et al. 2012 (Leptophoca lenis) | Phocine of medium size. Greater trochanter of femur
higher than head, its proximal part wider than its distal; distinct lesser trochanter located far below distal border of greater trochanter; trochanteric fossa deep, wide, and overhang- ing medioproximally; head large in relation to size of femur; minimum width of diaphysis situated proximally. | |
| L. Dewaele et al. 2017 | Large phocine, similar in size to large E. barbatus. The humerus of Leptophoca proxima differs from all other phocines in the following unique combination of characters: lesser tubercle of humerus small not reaching the proximal level of the humeral capitulum (also present in Praepusa vindobonensis, Prophoca rousseaui and
S. sintsovi); intertubercular groove wide and shallow (also present in C. cristata, E. barbatus and Prophoca rousseaui); relatively straight posterior margin of the humeral capitulum; deltopectoral crest extending along the proximal two-third of humerus (also present in C. maeotica, Phoca vitulinoides, Prae. vindobonensis, Prophoca rousseaui and S. sintsovi); deltopectoral crest terminating abruptly, distally, but less abrupt than in extant Phocinae (also present in Prophoca rousseaui); deltopectoral crest mediolaterally thin; lateral epicondyle thin and strongly projecting posteriorly; deep and well-outlined coronoid fossa (also present in Phoca spp. and Pusa spp.) Koretsky (2001) presented a diagnosis of the cranium and mandible of Leptophoca proxima (as Leptophoca lenis). However, this diagnosis is based on isolated skulls and skull fragments and mandibles. Without any supported association to Leptophoca proxima, i.e., association with the humerus, the designation of any cranial or mandibular specimen to Leptophoca proxima remains doubtful. Therefore, we acknowledge the diagnosis by Koretsky (2001), but neither accept nor reject it. Similarly, Koretsky (2001) tentatively assigned a significant number of isolated postcranial bones to Leptophoca proxima. However, given the abundance of humeri from the Calvert Formation and other formations of the Chesapeake Group (Neogene of the mid-Atlantic coastal plain, Delaware, Maryland, North Carolina, and Virginia) assigned to Leptophoca proxima, it can relatively safely be assumed that other phocine bones that have been found in relatively large numbers in the Chesapeake Group, such as femora and tibiae, can be related to Leptophoca proxima as well. Nevertheless, no femora or tibiae from the Neogene of Belgium can be assigned to Leptophoca proxima. Hence, because the current study focuses on material from Belgium, neither the femur nor the tibia of Leptophoca proxima will be treated in detail here. |
Measurements
No measurements are available
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| Source: f = family, c = class, uc = unranked clade | |||||
| References: Carreño and Cronin 1993, Nowak 1991, Gingerich 2003, Hendy et al. 2009 | |||||
Age range: base of the Burdigalian to the top of the Pliocene or 20.45000 to 2.58000 Ma
Collections (33 total)
| Time interval | Ma | Country or state | Original ID and collection number |
|---|---|---|---|
| Burdigalian | USA (Delaware) | Leptophoca lenis (18579) | |
| Burdigalian | Netherlands (Noord-Brabant) | Leptophoca amphiatlantica (123486) | |
| Langhian | USA (Virginia) | Leptophoca lenis (28368) | |
| Langhian | USA (Maryland) | Leptophoca lenis (18516 45506 70818 71615 71809) Leptophoca lenis, Leptophoca amphiatlantica (70823) | |
| Langhian - Serravallian | Belgium (Antwerpen) | Prophoca proxima (type locality: 51680) | |
| Langhian - Serravallian | Belgium | Prophoca proxima (59123) | |
| Serravallian | USA (Virginia) | Leptophoca lenis (55690 57111 71798 71806 126605 187324) Leptophoca lenis, Leptophoca amphiatlantica (45508) | |
| Serravallian | USA (Maryland) | Leptophoca lenis (49945 70828 70835 70836 70843 70854 88577 88578 88581 88582) | |
| Tortonian | Belgium (Antwerpen) | Prophoca proxima (52049 66960) | |
| Tortonian | USA (Maryland) | Leptophoca amphiatlantica (123487) | |
| Tortonian - Messinian | Belgium (Antwerpen) | Prophoca proxima (67022) | |
| Pliocene | USA (North Carolina) | Leptophoca lenis (123861) |