RECONSIDERATION OF ONTOGENETIC CHANGES OF THE MAXILLULA IN THE SPECIES OF GENUS LOXOCONCHA SARS, 1866 (CRUSTACEA, OSTRACODA, PODOCOPIDA)

  • Le Doan Dung
  • Nguyen Thi Phuong

Tóm tắt

Ostracod maxillula is the fourth head appendage and it is the one of key indicators in taxonomy, phylogeny and evolution. So far, some reports on ontogenetic changes of the maxillula of the genus Loxoconcha have been already published. In previous study, it was shown that the general development and number of setae on the maxillula are identical between the two species (L. noharai Le & Tsukagoshi, 2014 and L. japonica Ishizaki, 1968) of this genus from the second (A-7) to the fourth instars (A-5), and the differences  between the two species appear in and after the fifth instar (A-4). In the present report, by observation of the maxillulan ontogenetic changes in Loxoconcha sesokoensis Le & Tsukagoshi, 2014, the differences in the general development and number of setae among three Loxoconcha species (i.e., L. noharai Le & Tsukagoshi, 2014; L. japonica Ishizaki, 1968 and L. sesokoensis Le & Tsukagoshi, 2014) can be found at the earlier instar, the fourth instar (A-5). This finding contributes to the more accurate understanding of ontogenetic changes of maxillula and the phylogeny in the genus Loxoconcha.

Keywords: Loxoconcha, chaetotaxy, maxillula, taxonomy, phylogeny.

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2019-10-18
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