The diverse Grania fauna (Clitellata : Enchytraeidae) of the Esperance area, Western Australia, with descriptions of two new species

Seven species of the marine enchytraeid genus Grania Southern, 1913 are described from sediments sampled during the 2003 International Workshop on the Marine Flora and Fauna of Esperance Bay and the Recherche Archipelago, on the southern coast of Western Australia. Two species are new to science, the euryhaline Tasmanian G. dolichura Rota and Erseus, 2000 represents a new record for the state, and the remaining four species were known from other parts of Western Australia. Grania quaerens sp. n. is recognized by having a high chaetal index (= 5 short chaetal foot), small coelomocytes, penial apparati with long whip-like terminal stylets, conspicuous spermathecae with ectally bulbous ducts, and ectally granulated ampullae housing sperm rings in their ental region. Grania sperantia sp. n. is readily distinguishable by the complete lack of lateral chaetae, a multiple-banded pattern of the clitellum, extremely long sperm funnels, and the intrasegmental location of the spermathecal pores. The latter new species and four others in the collection (G. bykane Coates, 1990, G. crassiducta Coates, 1990, G. dolichura, and G. ersei Coates, 1990) are remarkable in possessing the head organ, a sensory structure unique to Grania that was not noted previously in Western Australian species. When considering the whole genus, the geographic pattern of the head organ appears southern-centred: of the 17 species of Grania reported to possess it, as many as 13 inhabit the southern latitudes. The seventh species of the Esperance collection, G. vacivasa Coates and Stacey, 1993, is notable for the kind of items found in its gut and the unusual appearance of its pygidium.

滇西上地幔铅同位素演化模式及滇西富碱斑岩铅同位素组成的诠释

大量的Pb同位素数据资料表明，滇西上地幔铅具两阶段演化历史，但又不是很好地吻合Stacey-Kramers的两阶段模式。本文依据Stacey-Kramers建造两阶段模式的基本原理，结合滇西地区上地幔铅同位素组成资料，拟合出了能更好地反映滇西上地幔铅同位素演化历史的二阶段模式并应用此模式对滇西富碱斑岩及其相关岩石的铅同位素组成做出诠释。