Vera-Silva Ana Luiza, Carvalho Fabrício Lopes, Mantelatto Fernando Luis
Laboratory of Bioecology and Crustacean Systematics (LBSC), Department of Biology, Faculty of Philosophy, Science and Letters at Ribeirão Preto (FFCLRP), University of São Paulo (USP), Avenida Bandeirantes 3900, 14040-901, Ribeirão Preto, São Paulo, Brazil.
Zootaxa. 2017 May 19;4269(1):44-60. doi: 10.11646/zootaxa.4269.1.2.
Macrobrachium jelskii is a freshwater shrimp endemic to South America, occurring in all major Brazilian basins. It is used in various activities, such as fishing, fishkeeping and even as food for humans and animals, and therefore its distribution is affected by anthropic influence. Misidentification of M. jelskii is recurrent because of its morphological similarity to some sympatric species such as M. amazonicum and M. acanthurus. Thus, the aim of this study is to redescribe M. jelskii, proposing some characteristics that allow for a clearer differentiation of this species when compared to other similar congeneric species that occur in South America. The informative characters were the size and the shape of the rostrum, the ratio of the carpus and chela, the ratio of the chela and carapace length and the shape of the carpus of the second pereiopod, as well as the ratio between the length of the internal pair of posterior spine of telson and median apex of the posterior margin of telson. Although the intraspecific variability is high, the combination of the characters mentioned herein, including a morphological key, is very useful and makes it easier to differentiate between these three species.
耶氏沼虾是一种南美洲特有的淡水虾，分布于巴西所有主要流域。它被用于各种活动，如捕鱼、观赏鱼养殖，甚至作为人类和动物的食物，因此其分布受到人类活动的影响。由于耶氏沼虾在形态上与一些同域物种（如亚马逊沼虾和棘刺沼虾）相似，其误认情况屡见不鲜。因此，本研究的目的是重新描述耶氏沼虾，提出一些特征，以便与南美洲其他相似的同属物种相比，能更清晰地鉴别该物种。具信息价值的特征包括额剑的大小和形状、腕节与螯的比例、螯与头胸甲长度的比例、第二对步足腕节的形状，以及尾节内后侧刺长度与尾节后缘中尖的比例。尽管种内变异性很高，但本文所述特征的组合，包括一个形态学检索表，非常有用，能更轻松地区分这三个物种。
