Systematics and phylogeny of the caryophyllidia-bearing dorids (Mollusca, Nudibranchia), with descriptions of a new genus and four new species from Indo-Pacific deep waters

Valdés, Ángel; Gosliner, Terrence M.

doi:10.1111/j.1096-3642.2001.tb00689.x

Cited by 33 publications

(45 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Among doridoidean nudibranchs, the Cryptobranchia were long thought to be a clade nested among phanerobranchs [e.g. in seminal analyses by Valdés and Gosliner (2001) and Valdés (2002a)], while actually phanerobranch lineages may split off a cryptobranch stemline (see Martynov et al 2009. The history of lineages that were assigned to and removed from the Cephalaspidea was reviewed by Brenzinger et al (2013b), and basal sacoglossan systematics by Kohnert et al (2013).…”

Section: The Thankless Task Of Presenting a Classification Of Opisthomentioning

confidence: 99%

Flashback and foreshadowing—a review of the taxon Opisthobranchia

et al. 2013

View full text Add to dashboard Cite

Opisthobranchia have experienced an unsettled taxonomic history. At the moment their taxonomy is in state of dramatic flux as recent phylogenetic studies have revealed traditional Opisthobranchia to be paraphyletic or even polyphyletic, allocating some traditional opisthobranch taxa to other groups of Heterobranchia, e.g. Pulmonata. Here we review the history of Opisthobranchia and their subgroups, explain their traditionally proposed relationships, and outline the most recent phylogenetic analyses based on various methods (morphology, single gene and multiple gene analyses, as well as genomic data). We also present a phylogenetic hypothesis on Heterobranchia that, according to the latest results, represents a consensus and is the most probable one available to date. The proposed phylogeny supports the Acteonoidea outside of monophyletic Euthyneura, the basal euthyneuran split into Nudipleura (Nudibranchia plus Pleurobranchoidea) and the recently established taxon Tectipleura. The latter divides into the Euopisthobranchia, containing most of the major traditional opisthobranch clades, and the Panpulmonata, with a mix of the former opisthobranch, putative allogastropod and pulmonate taxa. This "new euthyneuran tree" rejects the traditional taxa Opisthobranchia and Pulmonata, and, in particular, has profound implications for preconceived textbook scenarios of opisthobranch and pulmonate evolution, which must now be reconsidered. In the absence of systematic barriers, research communities-which have traditionally investigated marine and non-marine heterobranchs separately-need to interact and finally merge for the sake of science.

show abstract

Section: The Thankless Task Of Presenting a Classification Of Opisthomentioning

confidence: 99%

Flashback and foreshadowing—a review of the taxon Opisthobranchia

et al. 2013

View full text Add to dashboard Cite

show abstract

“…Indeed, several phylogenies of dorid nudibranchs have been proposed that utilize morphological characters exclusively (e.g. Gosliner and Johnson 1994;Gosliner 1996;Gosliner and Johnson 1999;Valdes and Gosliner 1999;Fahey and Gosliner 2001;Garovoy et al 2001;Valdes and Gosliner 2001;Dorgan et al 2002;Valdes 2002;Gosliner 2004). The phylogenetic trees derived from these analyses were not compared to trees developed from other data sets such as natural product chemistry or sperm ultrastructure.…”

Section: S] Faheymentioning

confidence: 99%

Comparison and cost benefit analysis of different data sets used for determining mollusc evolution: a case study of the cryptobranch nudibranch Halgerda (Mollusca: Gastropoda)

Fahey¹

2006

Rec West Aust Mus Sup

View full text Add to dashboard Cite

-Several approaches to examining the evolution of organisms have been tested over the past several decades. Specifically, morphological and molecular (DNA sequences) data sets are the most widely used methods to test a phylogenetic hypothesis. A cost benefit analysis of previously published studies of nudibranch mollusc phylogeny is presented. The previous studies utilized different types of data sets to derive hypotheses of relationships. The present cost benefit analysis examines the usefulness of the different data sets to verify an existing species level phylogeny. The existing hypothesis had been derived from morphological data only. Results of the present analysis indicate that two of the four data sets used, DNA sequence data and morphological characters, are the most effective when measured in terms of robustness of the resultant phylogeny and considering cost and time spent on the analysis. The other two data sets: sperm morphology and natural product chemistry were found to be valuable at higher taxonomic levels. Conclusions from the cost benefit analysis indicate that combinations of data can provide valuable insight into evolutionary relationships, allowing the researcher to further examine a hypothesis from various perspectives. Those perspectives include the molecular evolution of the organism, morphological character evolution, chemical evolution and reproductive evolution at a cellular level. Using a multidisciplinary approach to systematics reveals the complexities of evolution.

show abstract

“…The genus Halgerda has been recently reviewed Gosliner, 1999, 2001;Valdés and Gosliner, 2001;Valdés, 2002) and shown to be monophyletic and most closely related to the genus Asteronotus. Discodoris has been shown to be more distantly related, although within the same clade of radula-bearing cryptobranch dorids.…”

mentioning

confidence: 98%

“…Healy and Willan (1991) provided a limited description of the sperm of Asteronotus cespitosus and a drawing of the acrosomal complex and nuclear apex, but other details such as the morphology of the midpiece and glycogen piece were not fully documented. Valdés and Gosliner (2001) provided a thorough analysis of both the caryophyllidia-bearing dorids and of the cryptobranch dorids (in press), concluding that Asteronotus was more closely related to Halgerda than to any other dorid. Gosliner (1999, 2001) presented the first phylogenetic analyses of Halgerda based on morphological data (radular, reproductive, and external morphological characters) using Asteronotus as an outgroup.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Sperm ultrastructure in the nudibranch genus Halgerda with reference to other discodorididae and to chromodorididae (mollusca: Opisthobranchia)

Fahey

Healy

2003

Journal of Morphology

View full text Add to dashboard Cite

Comparative sperm ultrastructure within the molluscan nudibranch genus Halgerda (Discodorididae) was examined for the first time using transmission electron microscopy (TEM), based on 17 of the 35 known species. In addition, observations on two other discodorids are made to facilitate outgroup comparison with Halgerda, including one species of Discodoris (D. boholiensis) and Asteronotus cespitosus (currently accepted as the closest sister taxon to Halgerda). Comparison was also made with some genera of the Chromodorididae in view of sperm similarities. Spermatozoa of all species examined were of the complex, helical, elongate ( approximately 300-400 micro m) type characteristic of most heterobranch gastropods. These cells exhibit the following discrete regions (in anteroposterior sequence) : an acrosomal complex (composed of a rounded, membrane-bound vesicle and a column-like pedestal); a solid, helical nucleus; an elongate, helical midpiece (composed of an axoneme and associated nine coarse fibers, an enveloping mitochondrial derivative of matrix, and paracrystalline materials and glycogen helix); an annular complex; and a short glycogen piece. Of these regions, the midpiece is by far the longest, occupying over 90% of the total sperm length. Comparison with other members of the radula-bearing cryptobranch dorids reveals several sperm similarities to other genera in the clade, particularly those of other Discodorididae and also with the Chromodorididae. Comparison with previously studied genera reveals noteworthy sperm differences within the Discodorididae. The most notable differences are the internal structure of the acrosomal pedestal (long and homogeneous in Halgerda, Discodoris; short and homogeneous in Asteronotus; long and finely striated in Rostanga; oblong with angular electron-lucent striations in Jorunna) and the internal structure of the glycogen piece. The pronounced helical keels of most Halgerda and Discodoris nuclei contrast with the weakly helical nucleus of Asteronotus. Sperm features alone do not provide a means of defining the genus Halgerda or the family Discodorididae nor do they support the monophyletic status of the caryophyllidia-bearing dorids. Important sperm characters such as the acrosome, nucleus, and midpiece can often still be determined from specimens that have been initially fixed in formalin, then stored in ethanol for extended periods of time (i.e., museum material). Of all sperm features, the mitochondrial derivative of the midpiece is the most resistant to long-term fixation : the survival of acrosomal, nuclear, and axonemal components is variable, presumably a factor of prefixation autolysis, varied primary fixation times and temperatures, formalin quality, and duration of alcohol storage.

show abstract

Systematics and phylogeny of the caryophyllidia-bearing dorids (Mollusca, Nudibranchia), with descriptions of a new genus and four new species from Indo-Pacific deep waters

Cited by 33 publications

References 32 publications

Flashback and foreshadowing—a review of the taxon Opisthobranchia

Flashback and foreshadowing—a review of the taxon Opisthobranchia

Comparison and cost benefit analysis of different data sets used for determining mollusc evolution: a case study of the cryptobranch nudibranch Halgerda (Mollusca: Gastropoda)

Sperm ultrastructure in the nudibranch genus Halgerda with reference to other discodorididae and to chromodorididae (mollusca: Opisthobranchia)

Contact Info

Product

Resources

About