Maorichelys wiffeni n. gen. n. sp., una nueva tortuga marina del Eocene de Nueva Zelanda (Testudines: Dermochelyidae).
Palabras clave: Chelonii, Dermochelyidae, Maorichelys wiffeni n. gen. n. sp., humero, taxonomia, Nueva Zelanda, Eoceno.
MAORICHELYS WIFFENI N. GEN. N. SP., A NEW SEA TURTLE FROM THE EOCENE OF NEW ZEALAND (CHELONII: DERMOCHELYIDAE)
ABSTRACT: From the South Island of New Zealand a new Eocene genus of a sea turtle Maorichelys wiffeni n. gen. n. sp., is erected. The holotype, a fragment of a humerus, is described and compared in its features to the known species of the same age.
Key words: Chelonii, Dermochelyidae, Maorichelys wiffeni n. gen. n. sp., humerus, taxonomy, New Zealand, Eocene.
Fossil turtles from New Zealand are described by FORDYCE (1981) from Palaeogene, and by WIFFEN (1981) from the Late Cretaceous, which was correctly determined as Protostegidae/Chelospharginae indet., and FORDYCE (1991) in review.
From the neighbouring Australia KEAR (2003) listed Notochelone costata (Owen, 1882) from the Lower Cretaceous (Upper Albian) deposits of Queensland. The holotype specimen (AM F67326) is a partially preserved carapace (OWEN, 1882). KEAR & LEE (2005) described a well preserved large-bodied basal protostegid chelonioid Bouliachelys suteri, from the Early Cretaceous (Albian) of Australia. This indicates that early sea turtles were both larger and more diverse than previously thought. GAFFNEY (1981; 1991) reviewed Notochelone costata and Cratochelone berneyi Longman, 1915 (Albian of Queensland also), which belong to the Desmatochelyidae, but dermochelyids has been hitherto unknown from Australia.
The present humerus OU 22021 from New Zealand was described first by KOHLER (1994) and was put preliminarily into the genus Psephophorus. Although the specimen does not come from the type locality of Psephophorus terrypretchetti, it was used for the original description of the type material (KOHLER, 1995, 1996). Taking into account the geologic age, however, some features of OU 22021 show another relationship. This admits possibilities of a stratigraphic use.
[FIGURE 1 OMITTED]
GENERAL REMARKS ON EOCENE DERMOCHELYID HUMERI
The following genera of Dermochelyidae hitherto were described. Species with known humeri printed in boldface (see also KARL, 2002):
1. Arabemys Tong, Buffetaut, Thomas, Roger, Halawani, Memesch & Lebret, 1999, type species: Arabemys crassiscutata Tong et al. 1999 (dermal placoids known only).
2. Cosmochelys Andrews, 1920, type species: Cosmochelys dolloi Andrews, 1920 (only dermalplacoids and ribs known).
3. Dermochelys Blainville, 1816, type species: Dermochelys coriacea (Linnaeus, 1766) (all bone elements known).
4. Eosphargis Lydekker, 1889, type species: Eosphargis gigas (Owen, 1880), Eosphargis breineri Nielsen, 1959 (skull, trunks, girdles, extremities, dermal elements known).
5. Mesodermochelys Hirayama & Chitoku, 1996, type species: Mesodermochelys undulatus Hirayama & Chitoku, 1996 (nearly all bone elements known, see also HIRAYAMA & CHITOKU, 1996 and HIRAYAMA & NIKIDA, 1998).
[FIGURE 2 OMITTED]
6. Psephophorus H. v. Meyer, 1847, type species: Psephophorus polygonus H. v. Meyer, 1847, other species: Psephophorus scaldii Van Beneden, 1871, Psephophorus rupeliensis Van Beneden, 1887, Psephophorus calvertensis Palmer, 1909, Psephophorus eocaenus Andrews, 1901, [Psephophorus oregonensis Packard, 1940, Psephophorus terrypretchetti Kohler, 1995, Psephophorus pseudotracion Gervais, 1849], syn. Pseudosphargis Dames, 1894 (Pseudosphargis ingens (Koenen, 1891) (skull, trunks, girdles, extremities, dermal placoids known).
7. Protosphargis Capellini, 1884, type species: Protosphargis veronensis Capellini, 1884, syn. Protosphargis capellini Negri, 1893 (only epithecal shell elements known).
Eocene dermochelyid humeri are only known from Eosphargis gigas, Eosphargis breineri, Psephophorus eocaenus and OU 22021. KOHLER (1994) compared and discussed with the cast of the holotype in the Egyptian Geological Museum only and excludes the Stuttgart material described by DACQUE (1912). That material figured here in plate 1, figure 3-2 shows the correct reconstruction made by DACQUE. The present structure of the humerus of Psephophorus eocaenus (figure 2-1) is not comparable with OU 22021 (figure 2-5). The humerus of Eosphargis breineri (figure 2-7) show a very high development of the crista-like structures of the insertion of musculus teres major which forms a unit crista and the crista deltopectoralis, but neither are not fused together. The humerus of Eosphargis gigas (figure 2-6) is relatively closer to OU 22021 because it shows a flat wrinkled crista-like insertion. All other dermochelyid humeri like Psephophorus rupeliensis (figure 2-2), Psephophorus scaldii (figure 2-3) and Psephophorus calvertensis (figure 2-8) present different stages of development from the simple muscle insertions to crista-like structures in progressive connection with the crista deltopectoralis (KARL, 1994). The very end of this evolutional process shows Dermochelys coriacea (figure 2-4). Psephophorus calvertensis possesses its own features of these structures and is a valid species. In the degree status stage of connection between the crista-like structures of insertion of the musculus teres major and the crista deltopectoralis Psephophorus calvertensis can be considered as a direct ancestor of Dermochelys coriacea. Psephophorus calvertensis is known from the Miocene of Calvert Cliffs in Maryland, USA (PALMER, 1909), and is the first occurrence of Dermochelys dermal placoids reported from the Pliocene to Early Pleistocene of North Carolina (KOHLER, 1994).
REDESCRIPTION OF PSEPHOPHORUS EOCAENUS ANDREWS, 1901
According KOHLER (1996) the detailed description by ANDREWS (1901) seems to be quite optimistic, but the original specimen may show some features better than the cast of the holotype (BMNH R 3017). Only the basic features, like the orientation of the deltopectoral crest, can be readily observed and the "... ulnar crest (is) more prominent than in Psephophorus scaldii and the radial crest [= lateral process] more oblique". In 1906 he described this further as: "The whole body is strongly compressed dorsi-ventrally. The head so far as preserved, is strongly convex and somewhat triangular in outline. The ulnar crest projects further beyond the head than in Psephophorus scaldii or in Sphargis [= Dermochelys]. Between the anterior thickening, which terminates on the head, and the posterior border the surface of the shaft is concave on the upper and lower faces of the bone, but the ventral concavity is deepest. The part of the bone above the radial process [lateral process] is considerably more elongated in proportion to its width than in Psephophorus scaldii and still more than in c. The radial prominence is very strongly developed, but is divided into two or more separate knobs, as in Psephophorus, and is continued on the ventral face of the bone obliquely backwards, so that if the line of its direction were continued it would pass through the end of the ulnar process; in both [= Dermochelys] and Psephophorus the ridge is placed more tranversely" (ANDREWS, 1906).
Now, KOHLER (1996) proposes that in "some publications, however, a reconstructed version of the humerus of P. eocaenus is figured as showing a crista deltopectoralis separated into distinct knobs (DACQUE, 1912; MULLER, 1968; Kan, 1994). This reconstruction stands in sharp contrast to the type description given by ANDREWS, with a sketch of the original humerus drawn by Y. Attia (cited by KOHLER, 1996) from the Egyptian Geological Museum in 1994 [figure 3-1 here], and with my own observations. Despite the damage in this area on the holotype (as examined on cast BMNH R 3017), it appears to me that ANDREW's description is correct".
We can consider that the original type material from ANDREWS is much damaged and eroded (see figure 3-1), but he also described the knob-like muscle insertions. DACQUE (1912) founded the diagnosis of that species on much better material (plate 1) and gave the high end reconstruction of its habitus (figure 3-2).
[FIGURE 3 OMITTED]
The observations on DACQUE'S original material in 1994 shows us the accuracy of her reconstruction (figure 3-2). The prominence of the knob-like muscle insertions are clearly demonstreable:
SMNS no Thickness Thickness Difference (ex coll. at corpus at knob Markgr. 1904) 11243 a 16 27,5 11,5 11243 b 18 35 17 11243 c 23 35,5 12,5
According to earlier results (KARL, 1994) Psephophorus eocaenus is characterized by a very distinct processus radialis and two separated median tuberculi which are not in connection with a muscle insertion on the processus, and a foramen ectepicondylare which is situated outside the epicondylus. It is the only precise definition of that species.
[FIGURE 4 OMITTED]
Order Chelonii Brongniart, 1800 (Latreille, 1800)
Gigaorder Casichelydia Gaffney, 1975
Megaorder Cryptodira Gray, 1825
Parvorder Eucryptodira Gaffney, 1975
Suborder Polycryptodira Gaffney, 1984
Superfamily Chelonioidea Aggasiz, 1857
Family Dermochelyidae Gray, 1825
Maorichelys n. gen.
TYPE SPECIES: Maorichelys wiffeni, new species.
DISTRIBUTION: Eocene of South Pacific.
DIAGNOSIS: Processus minor nearly completely reduced, forming a knob; insertion of the musculus teres major forms an intertubercular hole; insertion of the musculus teres major forms a unit fused crista deltapectoralis which is fused with the crista lateralis.
Maorichelys wiffeni n. sp.
TYPE SPECIMEN: University of Otago-Dunedin, Paleontological collection, No. OU 22021 (figure 2-5, figure 3, plate 3).
LOCALITY: Boulder Hill near Dunedin (Otago): NZMS [New Zealand Mapping Series] 260 metric sheet 144 (1987): Grid reference: 054873: South Island of New Zealand (KOHLER, 1995).
HORIZON: Eocene, middle Bartonian (Wetzeliella hampdenensis Wilson, 1967), Burnside Formation, according to KOHLER, 1995.
ETYMOLOGY: Maori = with respect to the native people of New Zealand, chelys = Greek-a turtle; wiffeni = in honour of Joan Wiffen, affectionately known as "the Dragon Lady", who fervently maintains her passion and zeal for New Zealand's prehistoric flora and fauna, especially reptiles.
DIAGNOSIS: Same as the genus.
1. Processus minor well developed and contacts the caput humeri, present = 0, absent = 1;
2. processus minor nearly completely reduced and forms a knob, absent = 0, present = 1;
3. processus minor transformed to a processus radialis / lateralis, absent = 0, present = 1;
4. processus major higher than the caput numeri, present = 0, absent = 1;
5. insertion of the musculus teres major forms a rough fossa, absent = 0, present = 1;
6. insertion of the musculus teres major forms an intertubercular hole, absent = 0, present = 1;
7. insertion of the musculus teres major forms two tubercles or knobs, absent = 0, present = 1;
8. insertion of the musculus teres major forms two fused tubercles to cristae, absent = 0, present = 1;
9. insertion of the musculus teres major forms a unit fused crista deltapectoralis, absent = 0, present = 1;
10. crista deltopectoralis fused with crista lateralis, absent = 0, present = 1.
Plesiochelys 0000000000; Osteopygis 1000100000; Allopleuron 1000010000; Gigantatypus 0000????00; Eochelone 1000100000; Caretta 1000100000; Eretmochelys 1000100000; Chelonia 1000100000; Lepidochelys 1000100000; Natador 1000100000; Puppigerus 1000100000; Desmatochelys 1000010000; Chelosphargis 1000010000; Archelon 0100010000; Corsochelys 1000000000; Mesodermochelys 1000000000; Psephophorus 0010001110; Eosphargis 0011010011; Maorichelys 0011010011; Dermochelys 0010000011
OUTTREE BY DOLMOVE- Interactive Dollo and Polymorphism Parsimony (Joseph FELSENSTEIN)
(Dermochelys, (Maorichelys, (Eosphargis, (Psephophorus, (Mesodermochelys, (Corsochelys, (Archelon, (Chelosphargis, (Desmatochelys, (Puppigerus, (Natador, (Lepidochelys, (Chelonia, (Eretmochelys, (Caretta, (Eochelone, (Gigantatypus, (Allopleuron, (Osteopygis, Plesiochelys)))))))))))))))))))
OUTTREE BY PARS-Discrete character parsimony algorithm, version 3.6a3, shows 5 trees in all found (Joseph FELSENSTEIN)
(((Dermochelys: 0.00, (Maorichelys: 0.00, Eosphargis: 0.00): 2.00): 1.00, Psephophorus: 2.00): 2.00, Gigantatypus: 0.00, (Archelon: 1.00, (Chelosphargis: 0.00, Desmatochelys: 0.00, Allopleuron: 0.00): 1.00): 1.00, (Mesodermochelys: 0.00, Corsochelys: 0.00, (Puppigerus: 0.00, Natador. 0.00, Lepidochelys: 0.00, Chelonia: 0.00, Eretmochelys: 0.00, Caretta: 0.00, Eochelone: 0.00, Osteopygis: 0.00): 1.00): 1.00, Plesiochelys: 0.00) [0.2000]
(((Dermochelys: 0.00, (Maorichelys: 0.00, Eosphargis: 0.00): 2.00): 1.00, Psephophorus: 2.00): 2.00, (Archelon: 1.00, Gigantatypus: 0.00, (Chelosphargis: 0.00, Desmatochelys: 0.00, Allopleuron: 0.00): 1.00): 1.00, (Mesodermochelys: 0.00, Corsochelys: 0.00, (Puppigerus: 0.00, Natador. 0.00, Lepidochelys: 0.00, Chelonia: 0.00, Eretmochelys: 0.00, Caretta: 0.00, Eochelone: 0.00, Osteopygis: 0.00): 1.00): 1.00, Plesiochelys: 0.00) [0.2000]
(((Dermochelys: 0.00, (Maorichelys: 0.00, Eosphargis: 0.00): 2.00): 1.00, Psephophorus: 2.00): 2.00, (Mesodermochelys: 0.00, Corsochelys: 0.00, (Chelosphargis: 0.00, Desmatochelys: 0.00, (Archelon: 1.00, Gigantatypus: 0.00): 1.00, Allopleuron: 0.00): 1.00, (Puppigerus: 0.00, Natador: 0.00, Lepidochelys: 0.00, Chelonia: 0.00, Eretmochelys: 0.00, Caretta: 0.00, Eochelone: 0.00, Osteopygis: 0.00): 1.00): 1.00, Plesiochelys: 0.00) [0.2000]
(((Dermochelys: 0.00, (Maorichelys: 0.00, Eosphargis: 0.00): 2.00): 1.00, Psephophorus: 2.00): 2.00, Gigantatypus: 0.00, (Mesodermochelys: 0.00, Corsochelys: 0.00, (Archelon: 2.00, Chelosphargis: 0.00, Desmatochelys: 0.00, Allopleuron: 0.00): 1.00, (Puppigerus: 0.00, Natador: 0.00, Lepidochelys: 0.00, Chelonia: 0.00, Eretmochelys: 0.00, Caretta: 0.00, Eochelone: 0.00, Osteopygis: 0.00): 1.00): 1.00, Plesiochelys: 0.00) [0.2000]
(((Dermochelys: 0.00, (Maorichelys: 0.00, Eosphargis: 0.00): 2.00): 1.00, Psephophorus: 2.00): 2.00, Archelon: 2.00, Gigantatypus: 0.00, (Mesodermochelys: 0.00, Corsochelys: 0.00, (Chelosphargis: 0.00, Desmatochelys: 0.00, Allopleuron: 0.00): 1.00, (Puppigerus: 0.00, Natador. 0.00, Lepidochelys: 0.00, Chelonia: 0.00, Eretmochelys: 0.00, Caretta: 0.00, Eochelone: 0.00, Osteopygis: 0.00): 1.00): 1.00, Plesiochelys: 0.00) [0.2000]
TREE BY TREEVIEW (Roderic Page) based on Outtree 2 by DOLMOVE (Joseph Felsenstein) without Gigantotypus.
In all five trees Maorichelys stands closer to the genus Eosphargis than the genus Psepbophorus of Dermochelys. Plesiochelys is a sister taxon for all taxa used. Other closely related groups are the Cheloniidae (Puppigerus, Natador, Lepidochelys, Chelonia, Eretmochelys, Caretta, Eochelone) and Osteopygis, Mesodermochelys and Corsochelys as well as the Protostegidae (Archelon, Chelosphargis, Desmatochelys) and Allopleuron. General remarks on phylogeny of chelonioidea see HIRAYAMA (1994). The position of Gigantatypus (type species G. salahi Kaddumi, 2006) in this tree is still unclear because the ventral side of the gigantic humerus (length 67 cm, greatest width 30 cm) is unknown, since it is hidden under sediment (KADDUMI, 2006).
The main result of this analysis is OU 22021, a member of its own genus and species, described here as Maorichelys wiffeni n. sp. The comparative character analysis of this specimen shows a clear relation to the genus Eosphargis, but not to Psephophorus, and therefore it cannot be included into the type specimen of Psephophorus terrypretchetti Kohler, 1995. Furthermore, the type location of OU 22021 is not identical with that of the aforementioned specimen. On this basis Psephophorus terrypretchetti Kohler, 1995 shows no more different features to other Psephophorus-species founded on dermal placoids.
Special thanks are due to the following persons (here listed alphabetically) for various support with material in the collections under their care, as well as for supplying us with information and pictures: Dr. Ronald Bottcher-Stuttgart, Dr. Sandra Chapman-London, Dr. Ewan Fordyce, Dunedin, Dr. Richard Kohler-Ravensburne, Dr. Rupert Wild-Stuttgart. Layout of plates were prepared by Dirk Urban-Erfurt. Lisa Staley M.A., Vancouver reads the manuscript and edits/refines the English.
(FECHA DE RECEPCION: 2006-07-23) (FECHA DE ADMISION: 2006-09-13)
BIBLID [0211-8327 (2007) 43 (1); 11-24]
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Hans-Volker KARL, Geoscience Centre of the University of Gottingen. Division Geo-Biology. Goldschmidt Str. 3. D-37077 Gottingen, Germany. Correo-e: firstname.lastname@example.org orhkarl @uni-goettingen.de
Gottfried TICHY, Department of Geography and Geology. Division Geology and Evolutionary Research. University of Salzburg. Hellbrunner Strasse 34, A-5020 Salzburg, Austria. Correo-e: Gottfried.Tichy@sbg.ac.at
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|Author:||Karl, Hans-Volker; Tichy, Gottfried|
|Publication:||Studia Geologica Salmanticensia|
|Date:||Jan 1, 2007|
|Next Article:||Reptiles fosiles (Reptilia: Chelonii, Crocodylia) del Oligoceno inferior marino de la cuenca de Weisselster (Alemania Central: Sajonia).|