| Summary: | 碩士 === 國立臺灣海洋大學 === 環境生物與漁業科學學系 === 98 === Abstract
Hippidae belongs to the Infraorder Anomura, Order Decapoda, Class Malacostraca, Subphylum Crustacea. There are two genera and six species of hippid crabs of Taiwan in this study, including Hippa adactyla Fabricius, 1787, H. admirabilis (Thallwitz, 1892), H. marmorata (Hombron & Jacquinot, 1846), H. ovalis (A. Milne-Edwards, 1862), H. truncatifrons (Miers, 1878) and Mastigochirus gracilis (Thallwitz, 1892). H. marmorata is a new record from Taiwan. The morphological characters, identification keys, line drawings and color photographs of these species are provided as useful information for the studies in the future. There are approximately 27 known hippid species in the world. The hippids from Taiwan is about 22.2 % of the world or 35.2 % of the Indo-West Pacific. The hippid diversity of Taiwan is the highest in the Indo-West Pacific.
The reproductive ecology of H. ovalis from the intertidal zone near the estuary of Nan-ao River, Yilan County was studied. A total of 2029 specimens (1317 females and 712 males) of H. ovalis were collected from November, 2008 to December, 2009. Carapace length of female ranged from 9.2 to 36.9 mm, with mean carapace length 21.8±3.6 mm. Carapace length of male ranged from 11.0 to 26.1 mm, with mean carapace length was 18.8±2.0 mm. There is significantly difference (p < 0.05) in the ratios of carapace length and carapace width, carapace length and body weight between the sexs according to the analysis of covariance. The monthly sex ratios were significant difference (p < 0.05) from 1:1 in Chi-square test. Females outnumbered males in each monthly sample. H. ovalis are multiple spawners and reproduce all year round. Its main reproductive season is from May to October, with a peak in June and July. The fecundity and mean egg diameter (non-eyed) were 660 to 16817 eggs and 527±28 μm, respectively. The carapace length at first sexual maturity of female was around 18.1 mm, and male was around 16.0 mm. The reproductive activity of H. ovalis was significantly affected by air temperature from the multiple regression analysis. H. ovalis were parasitized by Halysiorhynchus macrocephalus (Shipley & Hornell, 1906) larva which belongs to the Phylum Platyhelminthes, Class Cestoda, Order Trypanorhyncha, Family Mixodigmatidae. H. macrocephalus is a new record from Taiwan. There is no evidence showing that how the parasite affected the reproduction of its host, H. ovalis.
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