Hoberg Eric P, Abrams Arthur, Pilitt Patricia A, Kutz Susan J
United States National Parasite Collection and Animal Parasitic Disease Laboratory, Agricultural Research Service, United States Department of Agriculture, BARC East, Building 1180, 10300 Baltimore Avenue, Beltsville, Maryland 20705, USA.
J Parasitol. 2012 Apr;98(2):355-64. doi: 10.1645/GE-2898.1. Epub 2011 Sep 23.
Collections to explore helminth diversity among free-ranging ungulates in the North American Arctic revealed the occurrence of a third male, or " davtiani ," morphotype for Teladorsagia boreoarcticus . Designated as T. boreoarcticus forma (f.) minor B, the males occurred with T. boreoarcticus f. major and T. borearcticus f. minor A in endemic populations of muskoxen (Ovibos moschatus wardi) and barrenground caribou (Rangifer tarandus groenlandicus) on Victoria Island, Nunavut, Canada, and in muskoxen and Peary caribou ( Rangifer tarandus pearyi ) on Banks Island, Northwest Territories, Canada. These specimens differ from conspecific morphotypes in the structure of the genital cone and Sjöberg's organ. Relative to T. boreoarcticus f. minor A, specimens of T. boreoarcticus f. minor B are consistently smaller, and mean dimensions for the bursa and spicules do not overlap. The robust spicules are similar in form, particularly in the relative length of the dorsal and ventral processes, but mean total length is substantially less in specimens of T. boreoarcticus f. minor B. Differences that distinguish the minor morphotypes of T. boreoarcticus parallel those demonstrated for the T. trifurcata and T. davtiani morphotypes in association with T. circumcincta sensu stricto. New host and geographic records include the 3 morphotypes of T. boreoarcticus in muskoxen and Peary caribou from Banks Island and in barrenground caribou from Victoria Island. Recognition of the ubiquitous nature of cryptic species emphasizes the need to effectively develop and use our collections-based resources and museum archives to build a robust understanding of the biosphere. Field inventory should include provisions for integrative approaches that preserve specimens suitable for comparative morphology, multi-faceted molecular investigations, and population genetics.
为探索北美北极地区自由放养有蹄类动物体内蠕虫多样性而进行的样本采集，发现了北方细颈线虫的第三种雄性形态，即“达夫蒂亚尼”形态。这种雄性形态被指定为北方细颈线虫小型B型，与北方细颈线虫大型型和北方细颈线虫小型A型一起，出现在加拿大努纳武特地区维多利亚岛的麝牛（Ovibos moschatus wardi）和北极驯鹿（Rangifer tarandus groenlandicus）的地方种群中，以及加拿大西北地区班克斯岛的麝牛和皮尔里驯鹿（Rangifer tarandus pearyi）中。这些样本在生殖锥和舍贝里氏器官的结构上与同种形态不同。相对于北方细颈线虫小型A型，北方细颈线虫小型B型的样本始终较小，且囊和交合刺的平均尺寸没有重叠。粗壮的交合刺在形态上相似，特别是背侧和腹侧突起的相对长度，但北方细颈线虫小型B型样本的平均总长度要短得多。区分北方细颈线虫小型形态的差异与在狭义环纹细颈线虫中发现的三叉细颈线虫和达夫蒂亚尼形态的差异相似。新的宿主和地理记录包括在班克斯岛的麝牛和皮尔里驯鹿以及维多利亚岛的北极驯鹿中发现的北方细颈线虫的3种形态。认识到隐性物种的普遍存在强调了有效开发和利用我们基于样本的资源和博物馆档案以深入了解生物圈的必要性。野外清查应包括采用综合方法的规定，以保存适合进行比较形态学、多方面分子研究和种群遗传学研究的样本。
