New non-native pseudocryptic Cyclorhipidion species (Coleoptera: Curculionidae: Scolytinae: Xyleborini) found in the United States as revealed in a multigene phylogeny

Pseudocryptic species, those that are difficult to diagnose using
traditional taxonomic methods, are serious impediments for recognizing the
introduction of non-native species. Rapid identification of species
facilitates a rapid response to newly introduced species which can lessen
their damaging effects. This situation is acute for known pest species
such as xyleborine ambrosia beetles which are difficult to identify given
minute morphological, often variable, diagnostic characters. These beetles
have been introduced into non-native temperate regions and have caused
economic and ecological havoc. In this study, we produced DNA-based
phylogenies using four genes for individuals of Cyclorhipidion bodoanum
(Reitter, 1913), C. distinguendum (Eggers, 1930), and C. pelliculosum
(Eichhoff, 1878) sampled from their introduced and native Asian ranges and
as well as other Cyclorhipidion species. In addition, we review subtle
morphological characters for diagnostic potential for these similar
species. Bayesian phylogenetic analysis produced well-resolved and
supported phylogeny that provided evidence for multiple introductions of
C. bodoanum and C. distinguendum into the US and the occurrence of
pseudocryptic species. The ambrosia beetles Cyclorhipidion tenuigraphum
(Schedl, 1953) and C. nemesis Smith & Cognato, sp. nov. are
reported in North America for the first time. We find that the pattern of
elytral interstrial setae is an unrealized source for the identification
of Cyclorhipidion species. This study resulted in the recognition of six
species adventive to the US with the revised status of C. californicum
(Wood, 1975). All species known from North American are diagnosed,
illustrated and a key is provided.

假隐存种（Pseudocryptic species），即难以通过传统分类学方法鉴定的物种，是识别外来物种引入的重大障碍。物种的快速鉴定有助于对新引入物种作出快速反应，从而减轻其危害。这种情况在已知害虫中尤为突出，例如材小蠹亚科食菌小蠹（xyleborine ambrosia beetles），因其形态诊断特征微小且常具变异性，难以鉴定。这些甲虫已被引入非原生温带地区，造成了经济和生态灾难。本研究中，我们利用四个基因对采自其引入地和亚洲原生地的Cyclorhipidion bodoanum（Reitter,1913）、C. distinguendum（Eggers,1930）、C. pelliculosum（Eichhoff,1878）个体及其他Cyclorhipidion属物种构建了基于DNA的系统发育树。此外，我们还评估了这些相似物种中具有鉴定潜力的细微形态特征。贝叶斯系统发育分析（Bayesian phylogenetic analysis）构建了分辨率高且支持度强的系统发育树，为C. bodoanum和C. distinguendum多次引入美国及假隐存种的存在提供了证据。食菌小蠹Cyclorhipidion tenuigraphum（Schedl,1953）和C. nemesis Smith & Cognato, sp. nov.首次在北美被报道。我们发现鞘翅行间刚毛（elytral interstrial setae）的形态模式是Cyclorhipidion属物种鉴定中尚未被利用的特征来源。本研究确认了6种引入美国的外来物种，并修订了C. californicum（Wood,1975）的分类地位。文中对北美已知的所有该属物种进行了鉴定、描述并提供了检索表。