A combined phylogenetic strategy illuminates the evolution of Goniodorididae nudibranchs (Mollusca, Gastropoda, Heterobranchia).

Goniodorididae is a family of small dorid nudibranchs distributed worldwide that feed on entoprocts, ascidians, and bryozoans. The evolutionary relationships between its taxa have been uncertain due to the limited taxa available for phylogenetic analyses; some genera being paraphyletic. The family includes a remarkable number of synonymized genera in which the species richness is unequally distributed, while some genera have dozens of species others are monospecific. Some clades are very uniform morphologically while others are considered highly variable. To increase backbone phylogenetic resolution a target enrichment approach of ultra-conserved elements was aimed at representative Goniodorididae species for the first time. Additionally, we increase species representation by including mitochondrial markers cytochrome c oxidase subunit I and ribosomal RNA 16S as well as nuclear Histone 3 and ribosomal RNA 18S from 109 Goniodorididae species, out of approximately 160 currently valid species. Maximum likelihood and Bayesian inference analyses were performed to infer the phylogeny of the family. As a result, two subfamilies and eleven genera were elucidated. The synonymized genera Bermudella, Cargoa, and Ceratodoris are here resurrected and a new genus, Naisdoris gen. nov., is described. The clades included taxa with shared prey preference, showing that trophic behavior could have driven species evolution and morphological uniqueness within the family Goniodorididae.

The first phylogenetic and species delimitation study of the nudibranch genus Gymnodoris reveals high species diversity (Gastropoda: Nudibranchia).

Nudibranchs are charismatic marine gastropods that lack a shell in the adult stage. While most nudibranchs feed on sessile animals such as sponges, bryozoans, and cnidarians, the nudibranch genus Gymnodoris Stimpson, 1855 evolved a more active and predatory lifestyle, including sea slug predation, cannibalism, and oddly enough, fish-fin parasitism. At the beginning of our work, no phylogenetic hypothesis existed for the genus, nor a clear picture of how Gymnodoris is related to other nudibranchs. Here we set out to reconstruct Gymnodoris phylogeny, investigate species diversity, and clarify the status of the genus name Analogium, which had been proposed for members of the genus with a linear gill filament arrangement. We present the first phylogenetic hypothesis for Gymnodoris, reconstructed by maximum likelihood and Bayesian inference using two mitochondrial and two nuclear loci, with gill filament arrangement plotted on the phylogeny. The backbone of the phylogeny remains unresolved with theseloci, however, we found that Gymnodoris comprises three main well-supported clades, which we refer to as the "subornata", "citrina" and "varied" clade, the latter two clades being comprised of several well-supported subclades. The sister group to Gymnodoris is a clade including the genera Vayssierea and Lecithophorus. Based on ABGD and PTP species delimitation methods, we conservatively estimate 65-70 species comprise our dataset. We further estimate that approximately 81% of the species we sampled are undescribed, and note that a linear gill filament arrangement has evolved multiple times within the genus. Gymnodoris is only monophyletic when the species with a linear gill arrangement are included. Therefore, at this time, we agree with the synonymy of Analogium striata with Gymnodoris striata by Rudman and Darvell (1990) and that the genus name Analogium is warranted as a junior synonym of Gymnodoris. Given the extensive undescribed diversity, and lack of resolution at some of the nodes in the phylogeny, patterns of diversification in diet are impossible to discern at this time and will require a large effort to both describe Gymnodoris species diversity and the diets of these candidate species.

A molecular phylogeny of Thuridilla Bergh, 1872 sea slugs (Gastropoda, Sacoglossa) reveals a case of flamboyant and cryptic radiation in the marine realm.

The genus Thuridilla Bergh, 1872 comprises mostly tropical sap-sucking sea slugs species with flamboyantly coloured forms. However, the potential for cryptic or pseudocryptic species masked by convergent or polymorphic colour patterns has not been tested using molecular characters. In this study, we sampled 20 of the 23 recognized worldwide species and performed the most comprehensive molecular phylogenetic analysis of the genus to date using a multi-locus approach combining two mitochondrial (cytochrome c oxidase subunit I, 16S rRNA) and two nuclear (Histone H3, 28S rRNA) genes using maximum likelihood, maximum-parsimony and Bayesian criteria. Three molecular species delimitation methods (ABGD, GMYC, bPTP) and the morphology of radular teeth were additionally used to aid in species delimitation. Our analyses supported 35 species within Thuridilla, of which more than one-third (13) are part of a single radiation here named the Thuridilla gracilis (Risbec, 1928) species-complex. This complex includes T. gracilis, T. splendens (Baba, 1949), T. bayeri (Er. Marcus, 1965), and T. ratna (Er. Marcus, 1965), plus nine additional undescribed species. All 13 species are distinguishable by radular characters, external morphology and their DNA. The detection of this radiation led diversity of Thuridilla to be underestimated by about 25% and provides a new comparative system for studying the role of colour patterns in marine diversification.

Cryptic ecological and geographic diversification in coral-associated nudibranchs.

Coral reefs are among the most biologically diverse ecosystems of the world, yet little is known about the processes creating and maintaining their diversity. Ecologically, corallivory in nudibranchs resembles phytophagy in insects- a process that for decades has served as a model for ecological speciation via host shifting. This study uses extensive field collections, DNA sequencing, and phylogenetic analyses to reconstruct the evolutionary history of coral-associated nudibranchs and assess the relative roles that host shifting and geography may have played in their diversification. We find that the number of species is three times higher than the number previously known to science, with evidence for both allopatric and ecological divergence through host shifting and host specialization. Results contribute to growing support for the importance of ecological diversification in marine environments and provide evidence for new species in the genus Tenellia.

An integrative approach to the systematics of the Berthella californica species complex (Heterobranchia: Pleurobranchidae).

Berthella californica (W. H. Dall, 1900) is a widespread species of heterobranch sea slug distributed across the North Pacific Ocean, from Korea and Japan to the Galapagos Islands. Two distinct morphotypes are observed in B. californica, which differ in external coloration, egg-mass morphology and geographic distribution (with the exception of a small range overlap in Southern California). Molecular and morphological data obtained in this study reveals that these two morphotypes constitute distinct species. The name B. californica (type locality: San Pedro, California) is retained for the southern morphotype, whereas the name Berthella chacei (J. Q. Burch, 1944) (type locality: Crescent City, California) is resurrected for the northern morphotype. Moreover, molecular phylogenetic analyses recovered B. californica as sister to Berthellina, in a well-supported clade separate from Berthella, suggesting that the classification of B. californica may need additional revision.

Flexible colour patterns obscure identification and mimicry in Indo-Pacific Chromodoris nudibranchs (Gastropoda: Chromodorididae).

Chromodoris is a genus of colourful nudibranchs that feed on sponges and is found across the Indo-Pacific. While this was once the most diverse chromodorid genus, recent work has shown that the genus should be restricted to a monophyletic lineage that contains only 22 species, all of which exhibit black pigmentation and planar spawning behaviour. Earlier phylogenies of this group are poorly resolved and thus additional work is needed to clarify species boundaries within Chromodoris. This study presents a maximum-likelihood phylogeny based on mitochondrial loci (COI, 16S) for 345 Chromodoris specimens, including data from 323 new specimens and 22 from GenBank, from across the Indo-Pacific. Species hypotheses and phylogenetic analysis uncovered 39 taxa in total containing 18 undescribed species, with only five of 39 taxa showing stable colour patterns and distinct morphotypes. This study also presents the first evidence for regional mimicry in this genus, with C. colemani and C. joshi displaying geographically-based variation in colour patterns which appear to match locally abundant congenerics, highlighting the flexibility of these colour patterns in Chromodoris nudibranchs. The current phylogeny contains short branch lengths, polytomies and poor support at interior nodes, which is indicative of a recent radiation. As such, future work will employ a transcriptome-based exon capture approach for resolving the phylogeny of this group. In all, this study included 21 of the 22 described species in the Chromodoris sensu stricto group with broad sampling coverage from across the Indo-Pacific, constituting the most comprehensive sampling of this group to date. This work highlights several cases of undocumented diversity, ultimately expanding our knowledge of species boundaries in this group, while also demonstrating the limitations of colour patterns for species identification in this genus.

Molecular phylogeny of Glossodoris (Ehrenberg, 1831) nudibranchs and related genera reveals cryptic and pseudocryptic species complexes.

Chromodorid nudibranchs (Chromodorididae) are brightly coloured sea slugs that live in some of the most biodiverse and threatened coral reefs on the planet. However, the evolutionary relationships within this family have not been well understood, especially in the genus Glossodoris. Members of Glossodoris have experienced large-scale taxonomic instability over the last century and have been the subject of repeated taxonomic changes, in part due to morphological characters being the sole traditional taxonomic sources of data. Changing concepts of traditional generic boundaries based on morphology also have contributed to this instability. Despite recent advances in molecular systematics, many aspects of chromodorid taxonomy remain poorly understood, particularly at the traditional species and generic levels. In this study, 77 individuals comprising 32 previously defined species were used to build the most robust phylogenetic tree of Glossodoris and related genera using mitochondrial genes cytochrome c oxidase subunit I and 16S, and the nuclear gene 28S. Bayesian inference, maximum likelihood, and maximum parsimony analyses verify the most recent hypothesized evolutionary relationships within Glossodoris. Additionally, a pseudocryptic and cryptic species complex within Glossodoris cincta and a pseudocryptic complex within Glossodoris pallida emerged, and three new species of Doriprismatica are identified.

Dating and biogeographical patterns in the sea slug genus Acanthodoris Gray, 1850 (Mollusca, Gastropoda, Nudibranchia).

Recent studies investigating vicariance and dispersal have been focused on correlating major geological events with instances of taxonomic expansion by incorporating the fossil record with molecular clock analyses. However, this approach becomes problematic for soft-bodied organisms that are poorly represented in the fossil record. Here, we estimate the phylogenetic relationships of the nudibranch genus Acanthodoris Gray, 1850 using three molecular markers (16S, COI, H3), and then test two alternative geologically calibrated molecular clock scenarios in BEAST and their effect on ancestral area reconstruction (AAR) estimates employed in LAGRANGE. The global temperate distribution of Acanthodoris spans multiple geological barriers, including the Bering Strait (∼5.32 Mya) and the Baja Peninsula (∼5.5 Mya), both of which are used in our dating estimates. The expansion of the Atlantic Ocean (∼95-105 Mya) is also used to calibrate the relationship between A. falklandica Eliot, 1905 and A. planca Fahey and Valdés, 2005, which are distributed in southern Chile and South Africa respectively. Phylogenetic analyses recovered strong biogeographical signal and recovered two major clades representing northern and southern hemispheric distributions of Acanthodoris. When all three geological events are applied to the calibration analyses, the age for Acanthodoris is estimated to be mid-Cretaceous. When the expansion of the Atlantic Ocean is excluded from our analyses, however, Acanthodoris is estimated to be much younger, with a divergence time estimate during the Miocene. Regardless of divergence estimates, our AAR suggests that Acanthodoris may have origins in the Atlantic Ocean with the Atlantic acting as a dispersal point to the northeastern Pacific. These results suggest that Acanthodoris exhibits a rare instance of western trans-arctic expansion. This study also shows that northeast Pacific specimens of A. pilosa should be regarded as A. atrogriseata and that A. serpentinotus should be regarded as a synonym of A. pina.

Family matters: The first molecular phylogeny of the Onchidorididae Gray, 1827 (Mollusca, Gastropoda, Nudibranchia).

Recent investigations into the evolution of the Onchidorididae using morphological based methods have resulted in low support for relationships among genera. This study aims to determine if molecular data corroborates recent morphological interpretations of the evolution of Onchidorididae. Five genetic markers: 16S, 18S, 28S, cytochrome c oxidase 1 (COI) and histone 3 (H3), were sequenced from 32 species comprising Onchidorididae and five other families, three from Phanerobranchia and two from Cryptobranchia. Phylogenies were estimated using maximum likelihood, and Bayesian inference analyses; with both yielding similar topologies. Molecular analyses resulted in high support for the monophyly of the suctorian clade and the placement of the genera within Onchidorididae. However, the Onchidorididae forms a paraphyletic grouping due to the recovery of the Goniodorididae and the Akiodorididae nested within family. In addition, the placement of Corambe as the most derived member of Onchidorididae is contradicted by the present study. Rather it is sister to a large clade that includes Acanthodoris and the species traditionally placed in Onchidoris and Adalaria, now defined as Onchidorididae. We have chosen to maintain Corambidae as a distinct taxon (including Corambe and Loy), sister to Onchidorididae. We also maintain Goniodorididae, Akiodorididae and Calycidoridae (including Calycidoris and Diaphorodoris), which along with the Onchidorididae and Corambidae comprise the suctorian superfamily Onchidoridoidea. Ancestral character reconstruction also suggests that the formation of a gill pocket, a character that currently defines the Cryptobranchia, may have evolved multiple times from an ancestor that lacked the ability to retract its gills into a fully formed gill pocket. The diversity of gill morphology displayed by the Onchidoridoidea will help give new insight into the evolution of this complex character within the Nudibranchia.

Phylogeny of the family Aglajidae (Pilsbry, 1895) (Heterobranchia: Cephalaspidea) inferred from mtDNA and nDNA.

The family Aglajidae includes several species of benthic, carnivorous cephalaspidean sea slugs, which generally lack a radula, have an internal shell, a posterior shield with short to moderate caudal lobes, and sensory cilia present on the head. The present study reports a phylogenetic analysis of the Aglajidae based on the mitochondrial genes 16S and CO1 and the nuclear gene H3, including 160 specimens of 54 species, that confirms the monophyly of Aglajidae as well as most taxonomically established genera, with some exceptions. Although support values are low for some clades, the analysis recovered the following clades within the Aglajidae: Odontoglaja, Nakamigawaia, and Melanochlamys. Chelidonura appears to be paraphyletic and the monophyly of a Chelidonura-Navanax-Aglaja clade is strongly supported in the Bayesian analysis, plus three of the four individual gene trees (COI, COI without 3rd codon positions, 16S and H3). However, the relatively low levels of support in the maximum likelihood analyses prevent us from proposing the synonymization of Navanax and Aglaja with Chelidonura. Melanochlamys is the sister clade of Chelidonura+Aglaja+Navanax. Odontoglaja is basal to the rest of the Aglajidae, confirming previous hypotheses on the loss of the radula in Aglajidae. Nakamigawaia and Melanochlamys are monophyletic, and should be maintained as valid. The monophyly of Philinopsis is strongly supported in the Bayesian analysis and in three of the four individual gene trees. Further research on this group is necessary to further affirm the monophyly of Chelidonura+Aglaja+Navanax and Philinopsis. Based on the results of this phylogenetic analysis, a reclassification of the taxonomy of Aglajidae is probably necessary. Additional genes should provide more information and probably fully resolve this situation. The present molecular study (including ABGD species delineation analyses) suggests the existence of previously undetected species complexes that require additional study to determine the extent of undocumented biodiversity.

Going further on an intricate and challenging group of nudibranchs: description of five novel species and a more complete molecular phylogeny of the subfamily Nembrothinae (Polyceridae).

Nembrothinae is a colourful subfamily of nudibranch polycerids, which despite its large size and striking appearance, needs to be more thoroughly studied. The available scientific information about this subfamily is very recent, and pictures of living undescribed species become available every day. Nevertheless, the lack of associated material for morphological, anatomical, and molecular analysis results in scarce additional studies. In this paper, five novel species are described: Roboastra ernsti sp. nov., Roboastra nikolasi sp. nov., Tambja brasiliensis sp. nov., Tambja crioula sp. nov., and Tambja kava sp. nov. In addition, Tambja divae (Marcus, 1958), a species previously known only from the original description, is redescribed and additional data and comments on Tambja cf. amakusana Baba, 1987 and Tambja marbellensis Schick and Cervera, 1998 are provided. Molecular data (H3, COI and 16S genes) for all these novel species and some additional ones were obtained and included in a previous molecular database. Maximum-likelihood, maximum-parsimony and Bayesian analyses were carried out. The phylogeny presented here has revealed Nembrothinae to be an intricate and challenging group of nudibranchs to study. Intermediate missing species seem to be critical to understanding the evolutionary relationships within this group.

Review of Baeolidia, the largest genus of Aeolidiidae (Mollusca: Nudibranchia), with the description of five new species.

This paper discusses the systematics of the aeolid genus Baeolidia Bergh, 1888. To date, this monophyletic genus is the most diverse within Aeolidiidae with sixteen valid species. Excluding Baeolidia cryoporos Bouchet, 1977, the genus is restricted to the Indo-Pacific and Eastern Pacific. Species of Baeolidia show a huge intrageneric variability in several morphological characters. Only oral glands, if present, may distinguish Baeolidia from other aeolidiids genera. Aeolidiella occidentalis Bergh, 1875, Aeolidiella faustina Bergh, 1900 and Spurilla orientalis Bergh, 1905 are transferred to Baeolidia but they are considered nomina dubia. Five new species, Baeolidia rieae sp. nov., Baeolidia variabilis sp. nov., Baeolidia lunaris sp. nov., Baeolidia gracilis sp. nov. and Baeolidia scottjohnsoni sp. nov. are described.

Battle of the bands: systematics and phylogeny of the white Goniobranchus nudibranchs with marginal bands (Nudibranchia, Chromodorididae).

Species identities of Goniobranchus nudibranchs with white bodies and various marginal bands have long been problematic. In this study, specimens of these Goniobranchus nudibranchs from the Philippines, Peninsular Malaysia, Japan, Papua New Guinea, and Madagascar were analyzed and molecular data were obtained in order to re-examine the relationships between species within this "white Goniobranchus with marginal bands" group. The analyses clearly recovered six species groups corresponding to the described species Goniobranchusalbonares, G.preciosus, G.rubrocornutus, G.sinensis, and G.verrieri as well as one new species, G.fabulus Soong & Gosliner, sp. nov. Notably, G.preciosus, G.sinensis, G.rubrocornutus, G.verrieri, and G.fabulus Soong & Gosliner, sp. nov. exhibit color variation and polymorphism, suggesting that some aspects of color patterns (e.g., presence or absence of dorsal spots) may not always be useful in the identification of species in the "white Goniobranchus with marginal bands" group, whereas other features such as gill and rhinophore colors and the arrangement and colors of the mantle marginal bands are more diagnostic for each species.

Molecular phylogeny and evolution of symbiosis in a clade of Indopacific nudibranchs.

Previous efforts at understanding the evolution of the genus Phyllodesmium, based on morphological analyses, have been plagued by poorly supported phylogenies (Ortiz and Gosliner, 2008; Moore and Gosliner, 2009, in press). It has been suggested (Moore and Gosliner, 2009) that a molecular phylogeny might provide more insight into this history than can be easily discovered using morphological data. In this study, 658bp of the cytochrome c oxidase subunit I gene (CO1), 441bp of the mitochondrial large ribosomal subunit (16S) gene, and 328bp of a protein-coding nuclear gene (histone 3) were sequenced for 18 species of Phyllodesmium and six outgroup species. A total of 464 parsimony informative sites were used for parsimony, maximum likelihood, and Bayesian inference of phylogeny analyses. All three analyses produced similar topologies, with the exception of a single difference within the parsimony analysis. Bootstrap values and posterior probabilities provided strong support at many shallow nodes, and the monophyly of Phyllodesmium was supported in every case. Three distinct clades of Phyllodesmium are evident in this analysis. One of these represents the majority of asymbiotic taxa. Phyllodesmium poindimiei, an asymbiotic species, is clearly a member of a symbiotic clade and appears to have secondarily lost its symbiotic relationship with zooxanthellae. There was moderate support confirming similar topological trends seen in earlier morphological phylogenies, including the hypothesis that symbiotic species associating with zooxanthellae have evolved more recently than non-symbiotic species. Despite the inclusion of a presumably conservative nuclear locus, some deep nodes are still unresolved or are not well supported. Future inclusion of additional taxa and more slowly evolving loci will likely improve resolution of these deeper nodes. The subsequent phylogeny supports previous hypotheses by Rudman (1991), Kempf (1991) and Burghardt et al. (2008b) that evolution of more complex digestive gland structures is related to increased complexity of symbiosis with zooxanthellae and greater efficiency of photosynthetic activity. Our phylogeny also demonstrates that this symbiosis has evolved only once in Phyllodesmium and that azooxanthellate species are sister, rather than basal, to zooxanthellate species.

Redescription of a forgotten nudibranch Miamira striata (Eliot, 1904) and review of the taxonomic status of the genus Orodoris (Nudibranchia: Chromodorididae: Miamirinae).

The genus Orodoris Bergh, 1875 is a small genus that together with Miamira Bergh, 1875, was considered as a junior synonym of Ceratosoma A. Adams Reeve, 1850. This decision was based on a morphological phylogenetic study conducted in 1999 that recovered the monophyly of the Ceratosoma. However, in 2012, molecular evidences led to the resurrection of Miamira, while Orodoris was retained as a junior synonym of Miamira with no further details. Here we revise the status of the genus Orodoris in light of the rediscovery of M. striata (syn. Orodoris striata Eliot, 1904). Our phylogenetic analysis revealed a close sister relationship between Miamira striata and Miamira miamirana Bergh, 1875 which nested within the Miamira clade. Therefore, to retain the monophyly of Miamira, the genus Orodoris should be maintained as a junior synonym of the former. This study proposes a neotype for M. striata and underscores the importance of reviewing historical taxonomic changes and investigating ancient descriptions prior to describing new taxa. Our study also confirms that Miamira magnifica Eliot, 1910 from the Indian Ocean and Miamira flavicostata Baba, 1940 from the Pacific Ocean represent two distinct, sister species.

The first molecular phylogeny of cladobranchian opisthobranchs (Mollusca, Gastropoda, Nudibranchia).

The first molecular phylogeny is presented for the highly diverse, opisthobranch molluscan Cladobranchia. This study, the most comprehensive for Cladobranchia to date, used new sequences of two mitochondrial and one nuclear genes for 95 specimens from 22 families and 38 genera with a species of Pleurobranchoidea as outgroup. Although our results do not resolve all the relationships within the Cladobranchia, there are significant findings that have implications for the systematics of the Cladobranchia. Cladobranchia represents a monophyletic group within the Nudibranchia with the exception of a clade containing species of Melibe. These species share a deletion of four codons in the COI gene that may account for their strong divergence from the remainder of the Cladobranchia. Bornellidae is the sister group to the rest of Cladobranchia, but this relationship is weakly supported. A series of well-supported clades within Cladobranchia show little structure as to their relationships to each other in the current analysis. The relationships of Tethys and Hancockidae to other Cladobranchia remain unresolved. Pseudobornella orientalis is here transferred to Dendronotus as D. orientalis. With this systematic change Bornellidae and Dendronotidae are now monophyletic. Lomanotus appears as the sister group to a monophyletic Aeolidida, but this relationship is not strongly supported. Scyllaeidae is monophyletic in this study with Scyllaea being sister taxon to Notobryon. The Proctonotidae are monophyletic and are clearly nested in the Cladobranchia. Dotoidae is monophyletic when Pinufius is included in this clade. Doriodomorpha is sister taxon to the Arminidae. Within Arminidae, Dermatobranchus and Armina, as they are presently constructed, are not monophyletic. There is an interesting potential sister group relationship between Dirona albolineata and Lemina millecra that requires additional exploration with expanded taxon sampling. In this study, Marianina rosea is nested within Tritoniidae, thus we consider Aranucidae, and its synonym Marianinidae, as a junior synonym of Tritoniidae to preserve the monophyly of Tritoniidae.

A tale of two genera: the revival of Hoplodoris (Nudibranchia: Discodorididae) with the description of new species of Hoplodoris and Asteronotus.

Nudibranchs in the family Discodorididae are generally medium (~30mm) to large ( 50mm) in size, sometimes cryptic, and are found in almost every marine ecosystem around the world. The diversity and systematics of the genera within Discodorididae are poorly understood and have led to numerous taxonomic changes. Hoplodoris Bergh, 1880 has recently been considered a synonym of Asteronotus Ehrenberg, 1831; however, morphological and molecular phylogenetic analyses reveal a distinct separation between these two genera. Here we provide a re-description of the type species Hoplodoris desmoparypha as well as descriptions of four undescribed species of Asteronotus and Hoplodoris. Bayesian inference and maximum likelihood analyses of two mitochondrial and two nuclear genes were used to evaluate the phylogenetic positions of the new species and clarify the relationships between Asteronotus and Hoplodoris to the rest of the Discodorididae. Based on our results, Hoplodoris is removed from synonymy with Asteronotus. Descriptions for Asteronotus markaensis sp. nov., and Asteronotus namuro sp. nov. from the Red Sea, as well as Hoplodoris balbon sp. nov. and Hoplodoris rosans sp. nov. from the western Pacific are provided.

Adding stars to the Chromodoris (Nudibranchia, Chromodorididae) galaxy with the description of four new species.

This paper describes four new Chromodoris species: Chromodoris balat sp. nov., Chromodoris baqe sp. nov., Chromodoris kalawakan sp. nov., and Chromodoris quagga sp. nov. We were able to distinguish 44 species level lineages within Chromodoris, expanding the Indo-Pacific species from 39 species. The phylogeny presented here provides slightly greater resolution of species relationships than do previous studies of this genus. Layton et al. (2018), determined that variable color patterns made it difficult to differentiate in living specimens of distinct species, but we provide some additional stable color characters that potentially help resolve this issue, as well as additional internal features that are useful in species delimitation and correlate with the molecular phylogenetic analysis.

Glossing over cryptic species: Descriptions of four new species of Glossodoris and three new species of Doriprismatica (Nudibranchia: Chromodorididae).

Advances in molecular systematics have led to a rapid increase in the identification of cryptic and pseudocryptic species in organisms exhibiting diverse and complex coloration with complicated taxonomic histories. A recent molecular phylogenetic analysis of nudibranchs in the genus Glossodoris (Mollusca: Gastropoda: Heterobranchia: Chromodorididae) and related genera identifies multiple cryptic and pseudocryptic species complexes, one within Glossodoris pallida and three within Glossodoris cincta, and support for three new species of Doriprismatica. Morphological analyses of color pattern, radular structure, buccal mass, and reproductive system support these identifications. Descriptions for Glossodoris buko sp. nov., Glossodoris bonwanga sp. nov., Glossodoris andersonae sp. nov., Glossodoris acosti sp. nov., and what will retain the name Glossodoris sp. cf. cincta are provided here, in addition to descriptions for new species Doriprismatica balut sp. nov., Doriprismatica rossi sp. nov., and Doriprismatica marinae sp. nov.. Glossodoris pallida and G. buko exhibit extreme differences in radular structure in addition to a clear biogeographic split in range. Glossodoris bonwanga, G. andersonae, G. acosti and G. sp. cf. cincta, share morphological and geographic differences but these are not as pronounced as in G. pallida and G. buko. More detailed study of the G. cincta complex is necessary to resolve some remaining systematic challenges. Doriprismatica balut is clearly distinct from all other congeners based on molecular and morphological characters. In contrast, D. rossi and D. marinae are not strongly divergent genetically, but have major morphological divergences that clearly distinguish them.

Molecular and morphological systematics of Dolabrifera Gray, 1847 (Mollusca: Gastropoda: Heterobranchia: Aplysiomorpha).

Molecular and morphological data from newly collected specimens and a review of the literature and type material indicate that the widespread tropical sea hare Dolabrifera dolabrifera is a species complex of five genetically distinct taxa. The name Dolabrifera dolabrifera is retained for a widespread species in the Indo-Pacific tropics. Dolabrifera nicaraguana is endemic to the eastern Pacific. Dolabrifera ascifera, D. virens and a new species described herein are restricted to the tropical Atlantic, with partially overlapping ranges in the Caribbean region and St. Helena. The temperate Pacific species Dolabrifera brazieri is also distinct and endemic to temperate southeastern Australia and New Zealand. These species of Dolabrifera constitute highly divergent lineages and most contain unique internal anatomical characteristics, particularly in the male reproductive morphology and shell shape, making them relatively easy to identify upon dissection. However, externally all these species are extremely variable in colour pattern and morphology and are virtually indistinguishable. This is particularly problematic for identification in the Atlantic Ocean where three species co-occur in the Caribbean region.