Structure, biodiversity, and historical biogeography of nematode faunas inHolarctic ruminants: Morphological and molecular diagnoses for Teladorsagia boreoarcticus N-sp (Nematoda : Ostertagiinae), a dimorphic cryptic species in muskoxen (Ovibos moschatus)
Ep. Hoberg et al., Structure, biodiversity, and historical biogeography of nematode faunas inHolarctic ruminants: Morphological and molecular diagnoses for Teladorsagia boreoarcticus N-sp (Nematoda : Ostertagiinae), a dimorphic cryptic species in muskoxen (Ovibos moschatus), J PARASITOL, 85(5), 1999, pp. 910-934
Discovery of the ostertagiine nematode Teladorsagia boreoarcticus n, sp, in
muskoxen, Ovibos moschatus, from the central Canadian Arctic highlights th
e paucity of knowledge about the genealogical and numerical diversity of ne
matode faunas characteristic of artiodactyls at high latitudes across the H
olarctic. Teladorsagin boreoarcticus is a dimorphic cryptic species disting
uished from Teladorsagia circumcincta/Teladorsagia trifurcata in domestic s
heep by a 13% divergence in the ND-I region of mitochondrial DNA constant d
ifferences in the synlophe, and significantly longer esophageal valve, spic
ules, gubernaculum, and bursa. Teladorsagin boreoarcticus represents an arc
haic component of the North American fauna and may have a Holarctic distrib
ution in muskoxen and caribou. Recognition of T. boreoarcticus in muskoxen,
in part, corroborates hypotheses for the existence of a cryptic species co
mplex of Teladorsagia spp. among Caprinae and Cervidae at high latitudes an
d indicates the importance of climatological determinants during the late T
ertiary and Pleistocene on diversification of the fauna. Also reinforced is
the concept of the North American fauna as a mosaic of endemic and introdu
ced species. Discovery of a previously unrecognized species of Teladorsagia
has additional implications and clearly indicates that (I) our knowledge i
s incomplete relative to potentially pathogenic nematodes that could be exc
hanged among domestic and wild caprines; (2) we do not hale sufficient know
ledge of the fauna to understand the ecological control mechanisms (limitat
ions) on dissemination and host range, and (3) on understanding of historic
al and geographical influences on the genealogical diversity and distributi
on of nematode faunas in domestic and wild ruminants is requisite to define
the interface between agricultural and natural ecosystems across the Holar
ctic.