Phosphatocopine ostracodes with preserved appendages from the Upper Cambrian of Sweden
DOI | 10.1111/j.1502-3931.1979.tb01234.x |
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Aasta | 1979 |
Ajakiri | Lethaia |
Köide | 12 |
Number | 1 |
Leheküljed | 1-27 |
Tüüp | artikkel ajakirjas |
Keel | inglise |
Id | 24114 |
Abstrakt
More than 400 specimens of phosphatocopine ostracodes. representing different moult stages of Vestrogothia. Falites and Hesslandona have been recovered, with body and appendage structures preserved in minute detail. from anthraconites in the Upper Cambrian of Sweden and drift boulders deriving from that area. The secondary phosphatization of these structures, leading to preservation. is extensively discussed. It comprises even the inner lamella, but the abdomen is not preserved. Hypostome and lower lip are well developed. The large antennula is composed of a basipodite with probably two podomeres and a long exopodite with up to 18 podomeres bearing long spines, forming a natatory organ, and a broad endopodite of two to three podomeres. The biramous organization of the antennula is a unique, most primitive feature of phylogenetic significance. The antennae and up lo four additional pairs of appendages are also biramous and similar to the antennulae, not yet differentiated for specialized functions. Only the last pair is uniramous, but a second branch may have developed in subsequent moult stages not represented in the material. The movement of food into the mouth was achieved by the endites of antennulae and antennae, a function transferred backwards to other appendages during the course of ostracode phylogeny and reflected in ontogenetic trends among Recent ostracodes. The phosphatocopines were nectobenthic, filtering plankton feeders.