New Data on the Systematics of Lynxes

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New Data on the Systematics of Lynxes

CAT NEWS
Issue 16, Spring 1992

by Rosa Garcia-Perea*

I conducted a morphological study of the genus Lynx based on a large sample, 488 specimens, consisting of skins, skulls and postcranial skeletons, and representing the four extant species of the genus (sensu Werdelin, 1981). Criteria for age and sex estimation were identified, based on tooth replacement, annual growth layers of cementum, rates of sutures, synchondroses and epiphyseal cartilages ossification, as well as on biometrical variables. The development of these characters was then analyzed with respect to age. Once the samples were classified by age and sex, morphological and mensural differences between the species were described, and variation within and between populations was analyzed, as sample sizes permitted.

A principal focus of my research involved a reevaluation of the taxonomic status of the Iberian lynx. Despite the evidence presented by Werdelin (1981, 1990) and Garcia-Perea et al. (1985), the specific status of the Iberian lynx is not generally accepted. Although Honacki et al. (Mammal Species of the World, 1982), listed it as a separate species, they included the comment: "Probably a race of Lynx". More recently, three authoritative taxonomic references (Tumlison, 1987; Sokolov, 1988; and Corbet and Hill, 1991) treated the Iberian population as a member of the Eurasian species. Clearly, there has not been enough published data to convince mammalogists that the Iberian lynx is a good species.

My own findings (1991), as summarized below, support recognition of four recent species: two living in the Palaearctic, Lynx lynx (Eurasian lynx) and Lynx pardinus (Iberian lynx); and two living in the Nearctic, Lynx canadensis (Canadian lynx) and Lynx rufus (bobcat).

Study of the cranium and postcranial skeleton revealed that the processes associated with postnatal development are very similar for all populations studied, but the chronology is not always the same. For example, Lynx pardinus matures faster in postcranial development, reaching the adult condition in proportions and degree of ossification at least six months earlier than Lynx lynx. This observation suggests the existence of a heterochronic change associated with the speciation process that resulted in the separate species. In contrast to the other species, samples of L. pardinus also exhibit a unique ossification pattern of the presphenoidal synchondrosis.

In qualitative morphological features, L. pardinus possesses the highest number of unique traits (10 of 30 coded) among the four species. Some characters traditionally used for distinguishing the two Palaearctic species (for example, presence of m1 metaconid, relative position of hypoglossal and posterior lacerate foramina) are inadequate for complete separation. I discovered one cranial character, the structure of the maxillary bone in relation to inferior oblique muscle fossa, that discriminates 100% of the individuals of the two Palaearctic species. This character is also useful to discriminate between the two Nearctic species.

Four well-defined pelage patterns were identified based on variation in size and arrangement of spotting (types A to D). Type A (large spots arranged in longitudinally oblique rows) is almost identical for L. pardinus and L. lynx, being very common in the Carpathian, Balkan and Caucasian populations of lynxes. Based on cranial traits and size, these populations clearly belong to L. lynx, but because of the frequency of occurrence of type A markings, authors have either assigned them to pardinus (e.g. Chappuis and Bologa, 1929; Djulic and Tortic, 1960; Dinnik, 1914) or included the Iberian population in lynx (e.g. Corbet and Hill, 1980; Tumlison,1987).

Another factor that confuses the taxonomic issue of Iberian and Eurasian lynxes is their present-day allopatric distributions. However, both forms were sympatric in southwestern Europe without evidence of intermediate forms during the Pleistocene (see, for example, Boule and Villeneuve, 1927; Dubois and Stehlin, 1933; Zeuner, 1959). By the 18th century, the two species had become allopatric due to the contraction of their ranges and population sizes (Kratochvil et al., 1967)

Based on external appearance and osteological features, many authors have considered Lynx canadensis as a close relative of L. lynx, and some have even viewed them as conspecific (Kurten and Rausch, 1959; Corbet and Hill, 1980; Tumlison, 1987; among others). The greatest difficulty of this issue concerns the allopatric occurrence of Canadian and Eurasian lynxes, but in this case, there is no fossil evidence of sympatry, nor has evidence of transitional forms in the area of Beringea been found (Kurten and Anderson, 1980).

Nevertheless, the number of qualitative character differences between the two species is similar to that observed in the other species of lynx. For these reasons, I regard Lynx lynx and Lynx canadensis as distinct species.

The bobcat and the Canadian lynx were found to share certain character similarities that do not appear in the Palaearctic species (for example, the shape of the posterior edge of the palate, absence of porosity in presphenoid bone). This character information contradicts the general belief that the Canadian lynx is more closely related to the Eurasian lynx than to the others (Kurten and Rausch, 1959; Werdelin, 1987). A re-examination of the phylogenetic relationships among the members of this genus is therefore warranted.

The results of my study support the specific recognition of the Iberian lynx, whose correct name should be Lynx pardinus (Articles 30 and 31 of International Code of Zoological Nomenclature, 1985), since I accept the generic usage of Lynx. The Iberian lynx warrants attention as one of the most endangered species of cats. I urge the development of captive-rearing programmes and its reintroduction into strictly protected areas.

* Address until August 1992:
Division of Mammals, MRC 108,
National Museum of Natural History,
Washington D.C. 20560, USA

After August 1992:
Museo Nacional de Ciencias Naturales,
C/ J. Gutierrez Abascal 2, 28006 Madrid, Spain

References

Boule, M. and J. Villeneuve. 1927. La grotte de l'Observatoire à Monaco. Archs. Inst. Paleontol., 1: 1-133 pp.

Chappuis, P. and V. Bologa. 1929. Fauna Ardealului, Banatului si parlitor ungurene in lumina cercetarilor mai recente in Transilvania Banat. Crisana, Maramures 1918-1925. Klausenburg, 1.

Corbet, G.B. and J.E. Hill. 1980. A World List of Mammalian Species.1st Ed. British Museum (Natural History) - Cornell University Press. London. 226 pp.

Corbet, G.B. and J.E. Hill. 1991. A World List of Mammalian Species. 3rd Ed. Natural History Museum Publications - Oxford University Press. London. 243 pp.

Dinnik, N.Y. 1914. Animals of the Caucasus. II. Carnivora. Tiflis.

Djulic, B. and M. Tortic. 1960. Verzeichnis der Saugetiere Jugoslawiens. Saugetierkundl. Mitteil., 8: 1-11.

Dubois, A. amd H.G. Stehlin. 1922. La grotte de Cotencher, station mousterienne. Mem. Soc. Paleont. Suisse (52, 53).

Garcia-Perea, R. 1991. Variabilidad Morfológica del Género Lynx Kerr, 1792 (Carnivora: Felidae). Tesis Doctoral. Ed. Universidad Complutense. Madrid. 555 pp.

Garcia-Perea, R.J. Gisbert and F. Palacios. 1985. Review of the biometrical and morphological features of the skull of the Iberian lynx, Lynx pardina (Temminck, 1824). Saugetierk. Mitt., 32: 249-259.

Honacki, J.H.; K.E. Kinman and J.W. Koeppl, Eds. 1982. Mammal species of the World. A taxonomic and geographic reference. Allen Press Inc. and The Association of Systematic Collections. Lawrence, Kansas.

I.C.Z.N. 1985. International Code of Zoological Nomenclature adopted by the XX General Assembly of the IUBS. International Trust for Zoological Nomenclature and British Museum (Nat. Hist.). London. 338 pp.

IUCN. 1990. Red List of Threatened Animals. IUCN - The World Conservation Union. 228 pp.

Kratochvil, J. et al.. 1967. History of the distribution of lynx in Europe. Acta Sc. Nat. Brno, 2 (4): 50 pp.

Kurten, B. and E. Anderson. 1980. Pleistocene Mammals of North America. Colombia University Press. New York.

Kurten, B. and R. Rausch. 1959. Biometric comparisons between North American and European Mammals. II. A comparison between the northern lynxes of Fennoscandia and Alaska. Acta Arctica, 11: 1-44.

Rodriguez, A. and M. Delibes. 1990. El lince ibérico (Lynx pardina) en España. Distribución y problemas de conservación. Ed. Instituto Nacional para la Conservación de la Naturaleza. 116 pp.

Sokolov, W.E. 1988. Dictionary of Animal Names in Five Languages. Mammals. Russky Yazyk Publishers. Moscow. 350 pp.

Tumlison, R. 1987. Felis lynx Linnaeus, 1758. Mammalian Species, No. 269: 1-8.

Werdelin,L. 1981. The evolution of lynxes. Ann. Zool. Fennici, 18: 37-71.

Werdelin, L. 1990. Taxonomic Status of the Pardel Lynx. Cat News, 13: 18.

Zenner, F.E. 1959. The pleistocene period. Its climate, chronology and faunal successions. 2nd Ed. London.

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