Description of two new epigean species of the genus Hyalella S.I. Smith, 1874 (Crustacea: Amphipoda: Hyalellidae) from Jalisco, Mexico

Abstract Two new species of Hyalella S.I. Smith, 1874 are described from state of Jalisco, Mexico. Hyalella marysolae sp. nov. can be identified by the presence of small projections or carinae on pleonites 1−2, with the first antenna being composed of 12 articles and the second antenna being composed of 15 articles. The first maxilla bearing 2−3 distal pappose setae, and the propodus in male first gnathopod is hammer-shaped. Conversely, in H. morronei sp. nov., dorsal projections or carinae are absent on pleonites 1−2, with the first antenna being composed of 10 articles and the second antenna of 14 articles. The first maxilla always bears two distal pappose setae, and the propodus in male first gnathopod is hatchet-shaped. Both species are distinguishable from other Hyalella species found in Mexico by the second antenna. In these two species, the second antenna is approximately half as long as the total body length, and the peduncle comprises 14 −15 articles; whereas, in other Mexican species, it is shorter and composed of maximum 12 articles. Here, we add two species to the four previously described in Mexico as it is necessary to increase the knowledge of the alpha taxonomy of this group of crustaceans and compensate for the biodiversity of the genus being underestimated.

摘要 本文记述了产自墨西哥哈利斯科州的透明钩虾属（Hyalella S.I. Smith, 1874）2个新种。玛丽索透明钩虾（Hyalella marysolae sp. nov.）可通过以下特征鉴别：第1-2腹节具小突起或隆脊，第一触角由12节构成，第二触角由15节构成；第一小颚具2-3根端位刷毛状刚毛，雄性第一螯足掌节呈锤形。莫龙透明钩虾（Hyalella morronei sp. nov.）则与之相反：第1-2腹节无背突起或隆脊，第一触角由10节构成，第二触角由14节构成；第一小颚始终具2根端位刷毛状刚毛，雄性第一螯足掌节呈斧形。两种新种均可通过第二触角与墨西哥已报道的其他透明钩虾属物种相区分：二者的第二触角长度约为体长的一半，柄部由14-15节构成；而墨西哥其他物种的第二触角更短，最多仅由12节构成。本次研究在墨西哥此前已记载的4个透明钩虾属物种基础上新增2个新种，以期深化对这类甲壳动物阿尔法分类学（alpha taxonomy）的认知，并填补该属生物多样性研究被低估的空白。