Review of Chinese Ranatrinae (Hemiptera: Nepidae), with descriptions of four new species of Ranatra Fabricius

Abstract

ognized by the following set of characteristics: aquatic bugs with the antennae hidden under the head, strongly modified raptorial fore legs, and caudally with a single narrow respiratory siphon which cannot be retracted into the apex of the abdomen. There are two main forms of Nepidae. The first one consists of oval or elongate oval, dorsoventrally flattened insects. They keep their forelegs with a strongly thickened femur horizontally in front, and combined with the respiratory siphon indeed remind one of small scorpions. Linnaeus (1758) gave the name of Nepa (Latin: scorpion) to the water bugs with prominent raptorial fore legs. The second form consists of elongate bugs, usually with a subcylindrical body, which keep their forelegs with elongated moderately thickened femora vertically in front. Fabricius (1790) split these subcylindrical forms off from genus Nepa, and gave them the name of Ranatra which is considered to be a fantasy name derived from Rana (Latin: frog). Most Ranatrinae species have a subcylindrical body, hence their vernacular name is water stick insects. The Ranatrinae occurring in China can be distinguished from other taxa of Nepidae by the following diagnosis: with a subcylindrical body, and the width of head across eyes larger than the anterior width of pronotum (figs. 1-3). The family Nepidae contains about 250 species, and is represented in all zoogeographical regions with the highest species densities in tropical areas. The family can be divided into two groups. Some authors (e.g. Lundblad 1933, De Carlo 1951, 1964) consider these as separate families, namely Nepidae and Ranatridae. More recent authors (e.g. Lansbury 1972a, 1974, Schuh & Slater 1995, Polhemus 1995) recognize two subfamilies: Nepinae (with ten genera) and Ranatrinae (with four genera). We follow the latter modern classifications and treat Ranatrinae as a subfamily of Nepidae. The Nepinae contain the real water scorpions, which are flat, more or less oval forms with thickened front femurs. Three genera of this subfamily have been found in China so far. (1) The genus Nepa contains five species occurring in the temperate zone of the Northern Hemisphere, two species occur in the northern part of China. (2) The genus Telmatotrephes Stal, 1854 holds six species, three in South America and three in Asia, of which T. chinensis Lansbury, 1972b, the only Chinese species, is only known from the holotype from Fujian Province, SE China. (3) Finally, the genus Laccotrephes Stal, 1866 is widely distributed in the Old World tropics and subtropics with about 80 species . This is the dominant genus of Nepinae in China with seven recorded species, and is distributed