Morphological differences between s

Morphological differences between species in the Synbranchiformes order are commonly used in systematic and biogeographical studies (Rosen & Rumney, 1972;Rosen & Greenwood, 1976; Favorito et al., 2005). However,many morphological traits can be subtle or ambiguous,which often makes it difficult to recognize and describe new species. Therefore, it is necessary to increase the number of tools and characteristics available for differentiating species from this group (Nakamoto et al., 1986; Foresti et al.,1992;Melilo et al., 1996; Sanchez & Fenocchio, 1996; Perdices et al., 2005; Torres et al., 2005; Nirchio et al., 2011; Carvalho et al., 2012). In the present study, several karyomorphs of S. marmoratus collected in distinct Brazilian river basins
were described. From these, sympatric karyomorphs were sampled in three distinct localities and the lack of reports of hybrids reinforces the hypothesis that exists as a species complex, which point the need of a deep taxonomic review
in this group.
The phylogenetic analyses evidenced the existence of five distinct groups (clades IA, IB, IC, ID and II) within S. marmoratus. However, these results suggest that such
grouping do not correspond to the five described karyomorphs reciprocally, indicating that not every karyomorph correspond to a unique species (e.g., karyomorph C), nor
a single species is represented by one karyomorph (e.g.,karyomorphs A and B). Therefore we propose the existence of, at least, five species within S. marmoratus complex.
Thus, karyomorphs D and E represent one species each;karyomorph C is split in two species; and karyomorph A and B represent one single species in initial stages of
differentiation. Although more detailed information concerning the geographic distribution of S. marmoratus specimens is needed, acquiring such data is often problematic; for example, these species are widely used as fisheries bait, which
can result in the widespread accidental introduction of these organisms into new environments. As a consequence of fish transposition, the specimens from karyomorph A sampled at Cáceres (Paraguay River basin) should be noted, as this karyomorph is positioned between two distinct branches of the dendrogram that includes specimens from the Parana River basin (Icém and Igaraçu do Tietê) (Fig. 4). Considering that many recreational fishermen frequent the Cáceres region, it is possible that these animals originated as bait fish from the Paraná River. Therefore, sample transposition
events can be very harmful and make biogeographical and historical studies in this group difficult.
The debate concerning the relationship between chromosomal rearrangements and speciation has been long and controversial (Trickett & Butlin, 1994; Rieseberg,2001; Noor et al., 2005; Hoffman & Rieseberg, 2008; Faria& Navarro, 2010). Although the data presented here are not strong enough to determine whether chromosomal alterations were the cause or consequence of speciation in Synbranchus, it was possible to demonstrate that within
subclade IB, two distinct karyomorphs (A and B) from nearby localities constitute the same haplotype and constitute a monophyletic group (Fig. 4). Namely, karyomorph B
contained a small pair of metacentric chromosomes,whereas karyomorph A lacked these chromosomes, a difference which most likely arose after the occurrence of a pericentric inversion in a submetacentric chromosome in karyomorph A (Fig. 3). Although small metacentric chromosomes can be observed in all other karyomorphs(with the exception of karyomorph A), the phylogenetic tree highlighted that this specific chromosome pair present in karyomorph B likely arose independently from the small metacentric chromosomes observed in the other samples,since this is a more parsimonious hypothesis than one claiming a common origin for these chromosomes at the base of the Synbranchus lineage with a more recent loss of these chromosomes in all karyomorph A lineages.

ผลลัพธ์ (อังกฤษ) 3:

在合鳃目物种之间的形态差异，常用的系统和生物地理学研究（罗森&Rumney，1972；罗森1976；&绿林，喜欢等人。，2005）。然而，许多形态特征可以是微妙的或模棱两可的，这往往使得它难以识别和描述新物种。因此，有必要增加工具和可鉴别的物种从这组特征数（中本聪等人。，1986；林中等人。，1992；Melilo等人。，1996；桑切斯，1996；&fenocchio，佩迪塞斯等人。，2005；托雷斯等人。，2005；nirchio等人。，2011；卡瓦略等，2012）。在目前的研究中，几个karyomorphs S.收集不同的巴西菖河流域
描述。从这些，同域karyomorphs在三个不同的地方，报道缺乏杂交的加强，作为一个物种存在复杂的假设采样，这一点深入的分类研究
本集团的需要。
系统发育分析证明五个不同的群体的存在（分支IA，IB，IC，ID和II）在美国鲉。然而，这些结果表明，这样的
分组不符合五所述karyomorphs相互，说明不是每个karyomorph对应于一个独特的物种（例如，karyomorph C），也不
单一物种是由一个karyomorph表示（例如，karyomorphs A和B）。因此，我们提出的存在，至少，在美国的五个物种。菖
复杂。因此，karyomorphs D和E代表每一个物种；karyomorph C是两种分裂；和karyomorph A和B代表在
分化初期单一的物种。虽然更详细的信息关于美国鲉标本的地理分布是必要的，获得这样的数据往往是有问题的；例如，这些物种被广泛用作渔业诱饵，这可能导致在新的环境中，这些生物的广泛的偶然引入。作为一个鱼换位后果的标本，在Cá谷神星karyomorph采样（巴拉圭流域）应注意，因为这karyomorph定位图，包括从巴拉那河流域标本两个不同分支之间（ICéM和igaraç你影响ê）（图4）。考虑到许多休闲渔民频繁CáCeres地区，很可能这些动物起源于饵料鱼从巴兰á河。因此，样本换位事件可以是非常有害的，生物地理和历史研究很难在这个组。
有关的染色体重排和形态之间的关系是长期的和有争议的辩论（赛&布特林，1994；2001；Rieseberg，努尔等人。，2005；霍夫曼，2008；法利亚&&Rieseberg，纳瓦罗，2010）。虽然这里给出的数据不足以确定染色体改变的原因或形态synbranchus后果，它可能表明，在
subclade IB，两种截然不同的karyomorphs（A和B）从附近的地区构成同一单倍型构成一个单系群（图4）。即，
karyomorph B包含一个小的双着丝粒染色体，而一个缺乏karyomorph这些染色体的差异，其中最有可能出现在发生在近端着丝粒染色体的臂间倒位在karyomorph一（图3）。虽然小的着丝粒染色体，可以观察到所有其他的karyomorphs（随着karyomorph一除外），系统进化树显示，这个特定的染色体对目前karyomorph B可能出现了独立的小的着丝粒染色体，其他样品中观察到的，由于这是一个更简洁的假设比一个声称共同的起源，这些染色体在synbranchus谱系的基础在所有这些染色体karyomorph一血统更近的损失。