Fryer G
Philos Trans R Soc Lond B Biol Sci. 1977 Feb 25;277(952):57-128. doi: 10.1098/rstb.1977.0007.
Six species of atyid prawns, representing five genera, occur in streams on the West Indian island of Dominica (figures 1-6). The ecology and habits of each are described and the relation of features of gross morphology to ways of life noted. Xiphocaris elongata, the most primitive living atyid, is a lightly built prawn whose adult habits are related to life in quiet pools in streams. An agile species and an excellent swimmer, it picks up individual small food particles with specialized chelipeds (figures 18 and 19) that differ from those of all other atyids and manipulates them with mouthparts (figure 77) which, while highly complex, are more primitive than those described for any other member of the family. Atya innocous and A. scabra, representing perhaps the most specialized atyid genus, are very similar in gross morphology and are robustly built ambulatory species. A. innocous is common in a variety of situations: A. scabra is rare and has been found only in fast-flowing water. Both have chelipeds whose three distal segments are extremely specialized (figure 36) and whose propus and dactylus are armed with an exceedingly complex array of long, slender bristles. These can be used either as brushes for collecting finely particulate detritus (figures 58-60) or as filtering fans (figures 68 and 69) which, held passively in flowing water, extract suspended particles. The Atyidae is unique among the Malacostraca in having representatives that filter passively by means of the chelipeds. The bristles (figure 40) are extended (figure 49), not by muscles, of which there are none in the distal parts of the propus and none anywhere in the dactylus, but by hydraulic forces. The return of the bristles to rest is by means of a cuticular spring. Some of the bristles of A. innocous are armed distally with minute denticles (figures 41 and 42) that facilitate scraping and sweeping: no such are present in A. scabra. The difference is related to the relative importance of scraping in the two species: A. innocous scrapes frequently, A. scabra seldom. Finely particulate food is transferred and manipulated by the extremely complex oral machinery (figure 78). One of the most elaborate parts of this is a teaselling device in which components of the maxillae and first maxillipeds participate (figures 80 and 81). The feeding mechanism is described. Morphologically and functionally Micratya poeyi can be regarded as a miniature version of Atya. It can both sweep and filter. Potimirim glabra is rare in Dominica and its habits but little known. Morphologically it is similar to, but more primitive than, Micratya. Its cheliped bristles are clearly specialized for sweeping and show few signs of being used for passive filtration. Jonga serrei occupies a separate and well-defined niche in the quieter parts of streams. For this it shows many morphological specializations and lacks such attributes as stout claws and robust walking legs that are the hallmark of its relatives living in fast-flowing waters.
西印度群岛多米尼克岛上的溪流中有6种匙指虾，分属于5个属（图1 - 6）。文中描述了每种匙指虾的生态和习性，并指出了其总体形态特征与生活方式的关系。长指剑额虾（Xiphocaris elongata）是现存最原始的匙指虾，体型轻盈，成年后的习性与溪流中平静水潭的生活相关。它行动敏捷，是出色的游泳者，能用特化的螯足（图18和19）捡起单个小食物颗粒，这些螯足与其他所有匙指虾的不同，并用口器（图77）进行操作，口器虽然高度复杂，但比该科其他任何成员所描述的口器更为原始。无害阿蒂虾（Atya innocous）和粗糙阿蒂虾（A. scabra）可能代表了最特化的匙指虾属，它们在总体形态上非常相似，是体型健壮的行动性物种。无害阿蒂虾在多种环境中都很常见；粗糙阿蒂虾很稀少，仅在水流湍急的水中被发现。它们都有螯足，其远端的三个节极度特化（图36），螯掌和指节上装备着极其复杂的一系列细长刚毛。这些刚毛既可以用作收集细颗粒碎屑的刷子（图58 - 60），也可以用作过滤扇（图68和69），被动地置于流动水中时可提取悬浮颗粒。匙指虾科在软甲纲中独一无二，其代表物种通过螯足进行被动过滤。刚毛（图40）伸展（图49）并非借助肌肉，在螯掌远端部分没有肌肉，指节上任何部位都没有肌肉，而是借助液压。刚毛恢复到静止状态是通过表皮弹簧。无害阿蒂虾的一些刚毛远端有微小的小齿（图41和42），便于刮擦和清扫；粗糙阿蒂虾则没有。这种差异与两种虾刮擦的相对重要性有关：无害阿蒂虾频繁刮擦，粗糙阿蒂虾很少刮擦。细颗粒食物由极其复杂的口部器官转移和操作（图78）。其中最精细的部分之一是一种起绒装置，上颚和第一小颚参与其中（图80和81）。文中描述了摄食机制。从形态和功能上看，波氏小阿蒂虾（Micratya poeyi）可被视为阿蒂虾的微缩版。它既能清扫又能过滤。光滑波氏虾（Potimirim glabra）在多米尼克很稀少，其习性鲜为人知。在形态上它与小阿蒂虾相似，但比小阿蒂虾更原始。它的螯足刚毛明显特化用于清扫，几乎没有用于被动过滤的迹象。塞氏容加虾（Jonga serrei）在溪流较安静区域占据着一个独立且明确的生态位。为此它表现出许多形态特化，缺乏粗壮的爪子和强健的步足等特征，而这些特征是生活在水流湍急区域的同类的标志。
