Department of Entomology, University of California, Riverside, CA, USA.
Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, TN, USA.
J Med Entomol. 2022 Jul 13;59(4):1217-1235. doi: 10.1093/jme/tjac057.
Tabanus variegatus F. 1805 has been called by the name Tabanus sulcifronsMacquart 1855 for over 80 yr; T. variegatus is one of the most common large horse flies attacking livestock in much of the southeastern U.S. Morphological, ecological, and molecular evidence indicates that T. variegatus is a distinct species, and we redescribe the female and describe the male. The Fabricius holotype, heavily damaged after over nearly 220 yr, is nevertheless taxonomically sound. Morphology (size, color, palp shape, and r5 wing cell shape) can usually distinguish T. variegatus from T. sulcifrons, but some specimens remain difficult to separate, especially in and west of the Mississippi River Valley. Using geometric morphometric analyses of the wing vein arrangement and palp shape the two species are significantly different. The wings of T. variegatus females also have more microsetae and sometimes a "frosty" appearance. Where they are common and sympatric, as in eastern Tennessee, they are temporally separated such that T. variegatus flies later (August-October) than T. sulcifrons (June-August), minimizing opportunity for gene flow. Museum specimens allow the approximate range of T. variegatus to be compared with that of T. sulcifrons s.l.; T. variegatus is particularly abundant from the coast of the Carolinas and Georgia east to central Tennessee and south to about central Alabama. DNA evidence (COI gene) recovers T. variegatus and T. sulcifrons s.s. in separate clades. Further studies on the T. sulcifrons complex are needed to fully resolve the range of both species, assess the degree of genetic substructuring, and examine relationships with other members of the T. sulcifrons complex.
斑虻属杂色亚种 F. 1805 已被误称为斑虻属凹刻亚种 Macquart 1855 长达 80 余年；该种虻是美国东南部大部分地区攻击牲畜的最常见的大型马蝇之一。形态学、生态学和分子证据表明，斑虻属杂色亚种是一个独特的物种，我们重新描述了雌性并描述了雄性。法比乌斯模式标本在经历了近 220 多年后严重受损，但在分类学上仍然是合理的。形态（大小、颜色、触须形状和 r5 翅室形状）通常可以区分斑虻属杂色亚种和斑虻属凹刻亚种，但有些标本仍然难以区分，特别是在密西西比河流域及其以西地区。使用翅膀脉序排列和触须形状的几何形态分析表明，这两个物种有显著差异。斑虻属杂色亚种雌性的翅膀也有更多的微刚毛，有时呈现出“霜状”外观。在它们共同存在和共存的地方，例如在田纳西州东部，它们的时间上是分开的，使得斑虻属杂色亚种的飞行时间较晚（8 月至 10 月），而斑虻属凹刻亚种的飞行时间较早（6 月至 8 月），从而最大限度地减少基因流的机会。博物馆标本允许将斑虻属杂色亚种的大致范围与斑虻属凹刻亚种 s.l.的范围进行比较；从卡罗来纳州和佐治亚州的海岸向东到田纳西州中部，再向南到阿拉巴马州中部，斑虻属杂色亚种特别丰富。DNA 证据（COI 基因）在单独的分支中回收了斑虻属杂色亚种和斑虻属凹刻亚种 s.s.。需要对斑虻属凹刻亚种复合体进行进一步研究，以充分确定两个物种的范围，评估遗传亚结构的程度，并研究与斑虻属凹刻亚种复合体其他成员的关系。
