Meland Kenneth, Mees Jan, Porter Megan, Wittmann Karl J
Department of Biology, University of Bergen, Bergen, Norway.
Flanders Marine Institute and Ghent University, Ostend, Belgium.
PLoS One. 2015 Apr 30;10(4):e0124656. doi: 10.1371/journal.pone.0124656. eCollection 2015.
The order Mysida (2 families, 178 genera, 1132 species) contains species across a broad range of habitats, such as subterranean, fresh, brackish, coastal, and surface to deep-sea habitats. The Stygiomysida (2 families, 2 genera, 16 species), however, are found primarily in subterranean waters, but always in waters with a marine influence. The Mysida and Stygiomysida body is divided into three main regions: cephalon, thorax, and abdomen. They are shrimp-like in appearance, containing morphological features earlier referred to as defining a "caridoid facies". The shrimp-like morphology was to some extent diagnostic for the historic Decapod taxon Schizopoda, containing the Nebalia, Mysida, Lophogastrida, and Euphausiacea. In 1904 the concept of Schizopoda was abandoned, and the Mysidacea (Mysida and Lophogastrida) along with Cumacea, Amphipoda, Isopoda, and Tanaidacea were placed in a new taxon, the Peracarida. Later discoveries of groundwater mysids led to the establishment of Stygiomysida, but placement to either Lophogastrida or Mysida remained unclear. The presence of oostegites and absence of podobranchiae, coupled with non-statocyst bearing uropods have been used to classify the Stygiomysida as a primitive Mysida family, comparable to Petalophthalmidae. On the other hand, equally suggestive characters, but for a Lophogastrida affiliation, was suggested for the archaic foregut characters and again, non-statocyst bearing uropods. With the inclusion of DNA sequence data of ribosomal genes, sister group relationships between Stygiomysida, Lophogastrida, and Mictacea within the Peracarida are observed, which supports a classification of the Stygiomysida as a separate order removed from the Mysida.
糠虾目（2科，178属，1132种）包含广泛栖息地中的物种，如地下、淡水、咸淡水、沿海以及从表层到深海的栖息地。然而，盲糠虾目（2科，2属，16种）主要发现于地下水域，但总是在受海洋影响的水域中。糠虾目和盲糠虾目的身体分为三个主要区域：头部、胸部和腹部。它们外观类似虾，具有一些形态特征，这些特征以前被认为是定义“类虾相”的特征。这种类似虾的形态在一定程度上是历史上十足目分类单元裂足亚目的诊断特征，裂足亚目包括叶虾属、糠虾目、宽虾目和磷虾目。1904年，裂足亚目的概念被摒弃，糠虾亚目（糠虾目和宽虾目）与涟虫目、端足目、等足目和异足目被归入一个新的分类单元——囊虾总目。后来对地下水糠虾的发现导致了盲糠虾目的建立，但它与宽虾目或糠虾目的归属仍不明确。育卵板的存在和 podobranchiae 的缺失，再加上无平衡囊的尾足，已被用于将盲糠虾目归类为一个原始的糠虾科，类似于花瓣虾科。另一方面，同样具有暗示性的特征，但表明与宽虾目有关联，是古老的前肠特征，同样还有无平衡囊的尾足。随着核糖体基因 DNA 序列数据的纳入，观察到了囊虾总目内盲糠虾目、宽虾目和微糠虾目之间的姐妹群关系，这支持将盲糠虾目分类为一个从糠虾目中分离出来的独立目。
