Glikmanius occidentalis ( Leidy, 1859 )

Ginter, Michał, Ivanov, Alexander & Lebedev, Oleg, 2005, The revision of “ Cladodus ” occidentalis, a late Palaeozoic ctenacanthiform shark, Acta Palaeontologica Polonica 50 (3), pp. 623-631 : 624-627

Glikmanius occidentalis ( Leidy, 1859)

Figs. 1A, C–E , 2A, B .

Hybodus ; Prestwich 1840, pl. 41: 12. Cladodus occidentalis ; Leidy 1859: 3. cf. Cladodus mortifer ; Newberry and Worthen 1866: 22, pl. 1: 5. cf. Cladodus gracilis ; Newberry and Worthen 1866: 30, pl. 1: 17. Cladodus mortifer Newberry and Worthen, 1866 ; St. John 1870:

431–432. Cladodus mortifer Newberry and Worthen, 1866 ; St. John 1872: 239–240,

pl. 6: a, b, pl. 13: a–d. Cladodus occidentalis ; Leidy 1873: 311–312, pl. 17: 4–6. Cladodus lamnoides Newberry and Worthen, 1866 ; Trautschold 1874:

286–288, text−fig.; cf. pl. 28: 3c–e; non pl. 18: 3a, b. Cladodus occidentalis ; Woodward 1889: 24. Cladodus mortifer Newberry and Worthen, 1866 ; Newberry 1897: 285,

pl. 22: 2. Cladodus girtyi sp. nov.; Hay 1900: 98–100, fig. 2. Cladodus girtyi Hay ; Hay 1902: 268. Cladodus mortifer Newberry and Worthen, 1866 ; Hay 1902: 269. Cladodus occidentalis Leidy ; Hay 1902: 269. Cladodus occidentalis Leidy ; Eastman 1903: 168, pl. 2: 3, 8, 9. Cladodus sp. ; Stukenberg 1905: 110, pl. 13: 24. Cladodus sp. ; Pavlov 1914: 19, fig. 7. Cladodus occidentalis Leidy ; Branson 1916: 652–653, pl. 2: 23, 24. Ctenacanthus occidentalis ; Glikman 1964a: pl. 1: 5. Ctenacanthus occidentalis (Leidy) ; Glikman 1964b: pl. 3: 10–12. Cladodus occidentalis Leidy ; Zidek 1973: fig. 2. Cladodus sp. ; Case 1973: figs. 13–18. Symmorium reniforme Cope ; Williams 1985: 107, pl. 7: 2–13. Symmorium reniforme ; Mapes and Hansen 1984: fig. 2. cf. Symmorium sp. indet.; Goto et al. 1988: 292, fig. 2, pl. 1: 1. Symmorium reniforme ; Hansen and Mapes 1990: fig. 171. Symmorium reniforme Cope ; Zidek 1992: 152–153, fig. 7. cf. Symmorium reniforme Cope ; Mertiniene 1995: 148, figs. 1, 2. Symmorium reniforme Cope ; Hansen 1996: 291, fig. 21−5.1. Symmorium occidentalis [sic] (Leidy); Lebedev 1996: 394, fig. 7A, B. Ctenacanthus volgensis A. Minikh , sp. nov.; Minikh and Minikh 1996:

262, pl. 5.4−I: 1a, b.? Symmorium lamnoides Newberry and Worthen, 1866 ; Lebedev 2001:

pl. 41: 3. cf. Ctenacanthus artiensis Kozlov , sp. nov.; Kozlov 2000: 152–153, pl.

3: 4 [non fig. 5]. Symmorium reniforme Cope ; Lucas and Estep 2000: 22–23, fig. 6A–O. “ Symmorium ” occidentalis (Leidy) ; Malysheva et al. 2000: fig. 2A–C. “ Cladodus ” occidentalis Leidy ; Ginter 2002: fig. 1D–F. “ Cladodus ” occidentalis ; Elliott et al. 2004: 275–276, fig. 4J–M.

Original diagnosis (from Leidy 1859: 3).—“Enameled crown, when perfect, about an inch in length, demi−conical; the outer convex side provided with narrow oblique folds. Lateral denticles two, the outer one the larger. Base of the tooth reniform, with a breadth of about an inch, and the short diameter about 5 lines; lateral extremities provided with a pair of large ovoid tubercles, one above the inner margin, the other below the outer margin.”

Description of the holotype, specimen ANSP 8394, from the upper Coal Measures of Manhattan, Kansas, by Leidy (1873: 311; see Fig. 1A ).—“The specimen has lost one−half of its base, a large portion of its principal cusp, and the points of the lateral cusps, but sufficient remains to give us a correct idea of the form of the perfect tooth.

The base of the tooth is oblong in outline, with the inner [= lingual] border somewhat angular and the outer [= labial] one concave. Its upper inner surface slopes from the cusps, and near its margin, a short distance from the extremities, supports a pair of oval tubercles. Similar protuberances occupy a position beneath the base externally.

The median or principal cusp of the tooth is elongated demiconical, with acute lateral edges. The inner convex surface of the cusp at its base exhibits sharp, oblique folds or striae. The outer less convex or nearly flat surface is smooth, except a few vertical wrinkles at its base.

The lateral denticles on each side of the principal cusp are two, of which the outer is the larger.

In its perfect condition the tooth has approximated 1 1/ 4 inches in length and about 1 inch in breadth at base.” Description based on additional material.— As evident from the literature and museum collections, numerous teeth of G. occidentalis were studied in Russia, USA, and England before and after the descriptions by Leidy (1859, 1873). Still more are yet unpublished. Based on all the material that was available to us, and especially, the specimens from the Moscovian of central Russia, from the Kazanian of the Uralian Foredeep, and from various Pennsylvanian formations of central and southwestern USA, we were able to add several details to the above characteristics of this species.

The lingual rim of the base seems to be “angular” in the holotype only because of partial abrasion. In most other specimens the lingual torus is trapezoidal indeed, but with the angles definitely rounded. In the type specimen, the basolabial projections differ in shape and size from the buttons. The former are smaller, with almost flat basal surfaces, whereas the surface of the buttons is more rounded. However, it was noted from several specimens that the buttons and projections can be almost equal in diameter. The buttons are not always circular, but they can be oval; usually they are situated rather close to the lingual rim ( Fig. 2B 1 ). On the aboral surface, a mesio−distal furrow occurs lingually to the basolabial projections.

The median cusp is relatively wide, with almost parallel lateral edges in the middle part ( Fig. 1C ). The lingual face of the median cusp is considerably convex, covered with moderate, subparallel, vertical, only slightly curved cristae ( Fig. 2A ). The labial face is deeply depressed basally, then becomes almost flat to slightly convex near the tip. The sculpture of the labial face is specific (see especially Glikman 1964b: pl. 3: 10): the cristae which begin at the basal depression, close to the midline, first turn slightly outwards, but at the midpoint of the cusp they become vertical and then turn back inward, parallel to the edges of the narrowing cusp, and gradually fade. The cristae which start at the base but in more outward position, are almost vertical and intersect the lateral edges of the median cusp rather soon. The uppermost part of the cusp on both labial and lingual sides is smooth ( Figs. 1C , 2A ).

The outer lateral cusps can be quite robust, but usually rather short. It appears that in all known specimens of this species, there is no more than one intermediate cusplet in the crown. A feature, characteristic of the whole genus, but particularly typical of G. occidentalis , must be emphasised here: because of the great depth of the basolabial indentation, framed by two projections, the intermediate cusplets are not in line with the median and outermost cusps, but are substantially displaced labially ( Figs. 1D , 2B 1 ).

Remarks.— The long synonymy list reflects the complex history of understanding this species, from the mid−19 th century up to recent times. Probably the first specimen representing this species, from the Coal Measures of Coalbrook Dale in England, was illustrated by Prestwich (1840: pl. 41: 12), under the name of Hybodus . No description of the tooth is provided and the woodcut, although very good, is slightly simplified. The artist drew an undivided basolabial rim, without any sign of basolabial projections, therefore the tooth looks like Cladodus bellifer . However, the original which is available for investigation at The Natural History Museum, London (P.7364), clearly shows an outline of a basolabial projection, typical of Glikmanius , on the preserved side of the base ( Fig. 1E ).

In 1859, Leidy’s brief, but clear description of the type specimen of Cladodus (now Glikmanius ) occidentalis , was published in the Proceedings of the Academy of Natural Sciences of Philadelphia. However, because he did not illustrate his new species, Leidy’s note apparently went unnoticed both by J. S. Newberry and O. H. St. John. Therefore, the latter used Newberry and Worthen’s (1866) name, “ C. ” mortifer , for the specimens he presented in his reports on Carboniferous vertebrates from Nebraska (St. John 1870, 1872). To clarify the priority situation, Leidy (1873) gave a longer description and illustrated his type specimen, synonymising “ Cladodus ” mortifer sensu St. John with “ C. ” occidentalis . That does not necessarily mean that the holotype of “ C. ” mortifer sensu Newberry and Worthen belongs in Glikmanius occidentalis , because the tooth is apparently lost and its drawing ( Newberry and Worthen 1866: pl. 1: 5) does not show diagnostic features.

Meanwhile, Trautschold (1874), evidently unaware of the discussion among American palaeontologists in the early 1870−s, described specimens of G. occidentalis from the vicinities of Moscow under another name from Newberry and Worthen’s (1866) paper, this time, “ Cladodus ” lamnoides (for photographic illustrations of Trautschold’s specimens, see Fig. 2A and Ginter 2002: fig. 1D–F). This mistake was noticed and corrected by Branson (1916: p. 653). From that time, until 1985, such forms were usually referred to as Cladodus occidentalis , with the exception of Glikman (1964a, b) who proposed the ctenacanth affinity of this species. Williams (1985) applied Cope’s (1893) name Symmorium reniforme to such teeth from the Pennsylvanian Black Shales. This unfortunate decision influenced many later authors for more than a decade, but the revision of the type material of S. reniforme ( Ginter 1998, 2002) definitely showed that teeth of the latter species are different in important aspects from those of G. occidentalis . They do have large median cusps and kidney−shaped bases, but such characters are insignificant, since they are typical of almost all cladodont sharks, with exception of Heslerodus and, perhaps, certain advanced stethacanthids.

It should be noted that one of the best collections of G. occidentalis teeth, from the Council Grove Group ( Lower Permian ) of Wabaunsee County, Kansas, is presented at Michael Everhart’s web page, http://www.oceansofkansas.com/ Leidy1859.html .

Distribution.—Pennsylvanian–Lower Permian marine deposits of USA (New Mexico, Arizona, Kansas, Indiana, Illinois, Ohio, Colorado); Pennsylvanian, Moscovian–Permian, Wordian (= Kazanian) of Russia (central and eastern Russian Platform, the Urals); Middle Permian of Japan (?).

Figures

Fig. 1. A. Glikmanius occidentalis (Leidy, 1859), holotype, specimen ANSP 8394, from the upper Coal Measures (Pennsylvanian) of Manhattan, Kansas, in lingual (A1), aboral (A2), and labial/aboral (A3) views. B. Glikmanius sp., specimen CM 44504B, from the Namurian E3, Bear Gulch, Montana, in lingual view. C–E. G. occidentalis. C. Specimen USNM 14107, from undetermined Carboniferous of Illinois, labial view. D. Specimen BMNH P.7043 (labelled as Cladodus impressus Woodward), from the Moscovian of Myachkovo, Moscow District, in lateral view. E. The first ever published specimen, BMNH P.7364, from the Chance Pennystone, Coal Measures of Donnington, Coalbrook Dale, Shropshire, UK, labial view. F, G. Glikmanius sp., photographs in aniseed oil, parts of occlusal view, specimen MP30−1, from the Serpukhovian of the Kalinovskie Vyselki Quarry, Moscow District. F. Lingual part of the base. G. Intermediate cusp. H. Lateral cusp.

Fig. 2. A, B. Glikmanius occidentalis (Leidy, 1859). A. Specimen PF 8240, from the Pennsylvanian black shales of the Hesler Quarry, Indiana, in oral/lingual view (same as Williams 1985: pl. 7: 7). B. Specimen PCh/425a, from the Moscovian of Myachkovo, Moscow District, in oral (B1) and aboral (B2) views. C. Glikmanius myachkovensis (Lebedev, 2001), specimen MB.f.9452.1, from the Moscovian of Myachkovo, in labial (C1), labial/aboral (C2), and aboral (C3) views.