Spatial distribution and egg production in squat lobsters (Decapoda: Munididae, Munidopsidae) from the collection of the Museu de Zoologia of the Universidade de São Paulo, Brazil

ABSTRACT: Spatial distribution and egg production of squat lobsters is examined from specimens deposited in the collection of the Museu de Zoologia of the Universidade de São Paulo (MZUSP), Brazil. A total of 1,346 specimens of squat lobsters were analyzed, out of which 169 were ovigerous females. Ovigerous females contained ten species of Munididae (n = 165) and three of Munidopsidae (n = 4). Eleven of the thirteen studied species were distributed along the Brazilian coast, while two of the remaining species in other marine regions. The analysis of bathymetric distribution revealed the presence of four species on the continental shelf (< 200 m depth: M. spinifrons, M. pusilla, M. irrasa, M. flinti), two on the first layer of the continental slope (200-500 m: Munida forceps, A. longipes) and five distributed between 500 and 1,048 m (M. erinacea, M. constricta, M. valida, M. microphthalma, M. transtridens). Overall, species belonging to Munididae produced a higher number of eggs (554 ± 619 eggs) but of minor size (0.48 ± 0.120 mm) than species of Munidopsidae (13 ± 10 eggs; 1.12 ± 0.337 mm, respectively). Such tendency is consistent with the phylogeny of both clades whose common origin is reflected in morphological similarities both in larval and adult forms, but not in terms of the reproductive strategy that clearly separates the species belonging to these families. Results also demonstrated that egg size in squat lobsters is strongly associated with depth, which suggests the strong influence of habitat on the duration of larval development of these species.

摘要：本研究以巴西圣保罗大学动物学博物馆（MZUSP）馆藏标本为研究材料，对铠甲虾（squat lobsters）的空间分布与怀卵特征展开分析。本次研究共分析1346号铠甲虾标本，其中169号为抱卵雌性个体。这些抱卵雌性个体分属10种穆氏铠甲虾科（Munididae）物种（n=165）与3种拟铠甲虾科（Munidopsidae）物种（n=4）。本次研究涉及的13个物种中，11个分布于巴西沿海海域，剩余2个分布于其他海洋区域。

对水深分布的分析结果显示：4个物种栖息于大陆架（水深<200米：M. spinifrons、M. pusilla、M. irrasa、M. flinti），2个物种栖息于大陆坡上层（水深200~500米：Munida forceps、A. longipes），另有5个物种分布于500~1048米水深区间（M. erinacea、M. constricta、M. valida、M. microphthalma、M. transtridens）。

总体而言，穆氏铠甲虾科物种的怀卵量（554±619粒）显著高于拟铠甲虾科物种（13±10粒），但卵径更小（0.48±0.120毫米）；拟铠甲虾科物种的怀卵量与卵径分别为13±10粒与1.12±0.337毫米。该趋势与两个演化支的系统发育关系相符：二者的共同起源体现在幼体与成体的形态相似性上，但生殖策略差异显著，可明确区分这两个科的物种。本研究同时发现，铠甲虾的卵径与水深存在显著相关性，这暗示栖息环境对该类群幼体发育时长具有强烈影响。