Statocyst content in Aeolidida (Nudibranchia) is an uninformative character for phylogenetic studies
Statocyst content in Aeolidida (Nudibranchia) is an uninformative character for phylogenetic studies
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Aeolidida(裸鳃亚纲)中的静囊含量对于系统发育研究来说是一个无信息的特征
DOI:
10.1093/mollus/eyab009
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发表时间:
2021
影响因子:
1.2
通讯作者:
Wägele
中科院分区:
文献类型:
--
作者:
Baumann;E.M.J.;Wägele
Morphological studies used to infer phylogenetic relationships rely on informative characters (Scotland, Olmstead & Bennett, 2003; Wiens, 2004). This means the characters should (1) carry some amount of phylogenetic information,(2) be specific for certain species, genera or families, and (3) not be randomly distributed. Statocysts were first described from heterobranchs in the 19th century (see review by Hoffmann, 1939) and have since been used in various morphological analyses (see Wägele & Willan, 2000). Statocysts have a spherical structure and the movement of the small, hard statoliths in these organs aids the animal’s orientation in space (eg Pelseneer, 1894; Crofts, 1937; Hoffmann, 1939; D’Asaro, 1966). Following Wägele & Willan (2000), statoliths can be clas-sified as otoliths (a statocyst containing a single statolith) or otoconia (statocysts containing multiple, small statoliths), as shown in Figure 1. While analysing histological slides of aeolid species, three character states were observed: the formerly used ‘single otolith’and ‘multiple otoconia’(Wägele & Willan, 2000), plus a third state, one characterized by both otoconia and otolith (s). Several studies have debated the usefulness of ‘statocyst content’(SC) as an informative morphological character. A taxonomic pattern in the distribution of SC has not been observed (Pelseneer, 1894; Ponder & Lindberg, 1997; Wägele & Willan, 2000). Moreover, different char-acter states of SC are known to occur even within the same genus. For these reasons, it is not clear whether SC is phylogenetically informative.The distribution of SC may not be taxonomically correlated. It may instead simply depend on the size of the statocyst, which in turn may depend on the size of the animal, or at least the size of the head region. To test this hypothesis, we measured the diameters of statocysts and the size of the head region (ie head area in crosssection) of several cladobranch species. The length of the animal was not considered, as it varies strongly within families and does not directly impact the amount of space within the head that can be occupied by statocysts. Whole specimens from 34 species (see Table 1; 1 member of Proctonotoidea and 33 members of Aeolidida) were preserved in formaldehyde/seawater, embedded in hydroxyethyl methacrylate (Kulzer® 7100), cross-sectioned (2.5 µm) and stained with toluidine blue. Histological slides from the
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DOI:
--
发表时间:
2000
期刊:
影响因子:
--
作者:
H. Wägele;R. Willan
通讯作者:
R. Willan
DOI:
--
发表时间:
--
期刊:
Mémoires couronnés et mémoires des savants étrangers, publiés par l'Académie royale des sciences, des lettres et des beaux-arts de Bruxelles. Collection in-4°
影响因子:
--
作者:
P. Pelseneer
通讯作者:
P. Pelseneer
DOI:
--
发表时间:
1937
期刊:
影响因子:
--
作者:
Doris R. Crofts
通讯作者:
Doris R. Crofts
影响因子:
0.9
作者:
D. Schillo;B. Wipfler;Nani Undap;Adelfia Papu;Nils Böhringer;Jan;F. Kaligis;R. Bara;T. Schäberle;G. König;H. Wägele
通讯作者:
H. Wägele