The adrenergic-induced ERK3 pathway drives lipolysis and suppresses energy dissipation.

Obesity-induced diabetes affects >400 million people worldwide. Uncontrolled lipolysis (free fatty acid release from adipocytes) can contribute to diabetes and obesity. To identify future therapeutic avenues targeting this pathway, we performed a high-throughput screen and identified the extracellular-regulated kinase 3 (ERK3) as a hit. We demonstrated that ß-adrenergic stimulation stabilizes ERK3, leading to the formation of a complex with the cofactor MAP kinase-activated protein kinase 5 (MK5), thereby driving lipolysis. Mechanistically, we identified a downstream target of the ERK3/MK5 pathway, the transcription factor FOXO1, which promotes the expression of the major lipolytic enzyme ATGL. Finally, we provide evidence that targeted deletion of ERK3 in mouse adipocytes inhibits lipolysis, but elevates energy dissipation, promoting lean phenotype and ameliorating diabetes. Thus, ERK3/MK5 represents a previously unrecognized signaling axis in adipose tissue and an attractive target for future therapies aiming to combat obesity-induced diabetes.

Triazolo[4,5-d]pyrimidin-5-amines based ERK3 inhibitors fail to demonstrate selective effects on adipocyte function.

Extracellular signal-regulated kinase 3 (ERK3 also designated MAPK6 - mitogen-activated protein kinase 6) is a ubiquitously expressed kinase participating in the regulation of a broad spectrum of physiological and pathological processes. Targeted inhibition of the kinase may allow the development of novel treatment strategies for a variety of types of cancer and somatic pathologies, as well as preserving metabolic health, combat obesity and diabetes. We chose and synthesized three triazolo [4,5-d]pyrimidin-5-amines proposed previously as putative ERK3 inhibitors to assess their selectivity and biological effects in terms of metabolic state impact in living cells. As it was previously shown that ERK3 is a major regulator of lipolysis in adipocytes, we focused on this process. Our new results indicate that in addition to the previously identified lipolytic enzyme ATGL, ERK3 also regulates hormone-sensitive lipase (HSL) and monoglyceride lipase (MGL). Moreover, this kinase also promotes the abundance of fatty acid synthase (FASN) as well as protein kinase cAMP-activated catalytic subunit alpha (PKACα). To investigate various effects of putative ERK3 inhibitors on lipolysis, we utilized different adipocyte models. We demonstrated that molecules exhibit lipolysis-modulating effects; however, the effects of triazolo [4,5-d]pyrimidin-5-amines based inhibitors on lipolysis are not dependent on ERK3. Subsequently, we revealed a wide range of the compounds' possible targets using a machine learning-based prediction. Therefore, the tested compounds inhibit ERK3 in vitro, but the biological effect of this inhibition is significantly overlapped and modified by some other molecular events related to the non-selective binding to other targets.

Design of Fluorescent Carbon Dots (CDs) for the Selective detection of Metal-Containing Ions.

The pollution caused by heavy metals (HMs) may occur through both natural processes and anthropogenic activities and is found in complex media. The purpose of this review is to summarize the state-of-art of fluorescent CDs and the sensing applications in a systematic manner. This review intends to provide clues on the origin on the observed selectivity in chemiluminiscence sensors, which was until now a stated but unaddressed question, and still remains open for debate. Indeed, it is tempting to think that CDs possessing functional groups with soft bases at the surface are able to detect soft metal acids, while the opposite is to be suspected for hard acid-base pairs. However, the literature shows several examples where this trend does not hold. We found that such observation is explained by the involvement of dynamic quenching, which does not involve the formation of a non-fluorescent complex, as in the case of static quenching. We have provided an interpretation of published data that was not provided by the original authors and offer guidelines to enable the design of CDs to target ions in solution.

57Fe Mössbauer and DFT study of the electronic and spatial structures of the iron(II) (pseudo)clathrochelates: the effect of ligand field strength.

Combined experimental 57Fe Mössbauer and theoretical DFT study of a series of iron(II)-centered (pseudo)macrobicyclic analogs and homologs was performed. The field strength of the corresponding (pseudo)encapsulating ligand was found to affect both the spin state of a caged iron(II) ion and the electron density at its nucleus. In a row of the iron(II) tris-dioximates, passing from the non-macrocyclic complex to its monocapped pseudomacrobicyclic analog caused an increase both in the ligand field strength and in the electron density at the Fe2+ ion, and, therefore, a decrease in the isomer shift (IS) value (so-called "semiclathrochelate effect"). Its macrobicyclization, giving the quasiaromatic cage complex, caused a further increase in the two former parameters and a decrease in IS (so-called "macrobicyclic effect"). The trend of their IS values was successfully predicted using the performed quantum-chemical calculations and the corresponding linear correlation with the electron density at their 57Fe nuclei was plotted. A variety of different functionals can be successfully used for such excellent prediction. The slope of this correlation was found to be unaffected by the used functional. In contrast, the predictions of both the sign and the values of quadrupole splitting (QS) for them, based on the theoretical calculations of EFG tensors, were found to be a real great challenge, which could not be solved at the moment even in the case of these C3-pseudosymmetric iron(II) complexes with known XRD structures. The latter experimental data allowed us to deduce a sign of the QSs for them. The straightforwarded molecular design of a (pseudo)encapsulating ligand is proposed to control both the spin state and the redox characteristics of an encapsulated metal ion.

Precise Fingerprint Determination of Vibrational Infrared Spectra in a Series of Co(II) Clathrochelates through Experimental and Theoretical Analyses.

The energetic demands of modern society for clean energy vectors, such as H2, have caused a surge in research associated with homogeneous and immobilized electrocatalysts that may replace Pt. In particular, clathrochelates have shown excellent electrocatalytic properties for the hydrogen evolution reaction (HER). However, the actual mechanism for the HER catalyzed by these d-metal complexes remains an open debate, which may be addressed via Operando spectroelectrochemistry. The prediction of electrochemical properties via density functional theory (DFT) needs access to thermodynamic functions, which are only available after Hessian calculations. Unfortunately, there is a notable lack in the current literature regarding the precise evaluation of vibrational spectra of such complexes, given their structural complexity and the associated tangled IR spectra. In this work, we have performed a detailed theoretical and experimental analysis in a family of Co(II) clathrochelates, in order to establish univocally their IR pattern, and also the calculation methodology that is adequate for such predictions. In summary, we have observed the presence of multiple common bands shared by this clathrochelate family, using the B3LYP functional, the LANL2DZ basis, and effective core potentials (ECP) for heavy atoms. The most important issue addressed in this article was therefore related to the detailed assignment of the fingerprint associated with cobalt(II) clathrochelates, which is a challenging endeavor due to the crowded nature of their spectra.

Protein kinase D1 deletion in adipocytes enhances energy dissipation and protects against adiposity.

Nutrient overload in combination with decreased energy dissipation promotes obesity and diabetes. Obesity results in a hormonal imbalance, which among others activates G protein-coupled receptors utilizing diacylglycerol (DAG) as secondary messenger. Protein kinase D1 (PKD1) is a DAG effector, which integrates multiple nutritional and hormonal inputs, but its physiological role in adipocytes is unknown. Here, we show that PKD1 promotes lipogenesis and suppresses mitochondrial fragmentation, biogenesis, respiration, and energy dissipation in an AMP-activated protein kinase (AMPK)-dependent manner. Moreover, mice lacking PKD1 in adipocytes are resistant to diet-induced obesity due to elevated energy expenditure. Beiging of adipocytes promotes energy expenditure and counteracts obesity. Consistently, deletion of PKD1 promotes expression of the ß3-adrenergic receptor (ADRB3) in a CCAAT/enhancer binding protein (C/EBP)-α- and δ-dependent manner, which leads to the elevated expression of beige markers in adipocytes and subcutaneous adipose tissue. Finally, deletion of PKD1 in adipocytes improves insulin sensitivity and ameliorates liver steatosis. Thus, depletion of PKD1 in adipocytes increases energy dissipation by several complementary mechanisms and might represent an attractive strategy to treat obesity and its related complications.

Targeting ERK3/MK5 complex for treatment of obesity and diabetes.

Kinases represent one of the largest druggable families of proteins. Importantly, many kinases are aberrantly activated/de-activated in multiple organs during obesity, which contributes to the development of diabetes and associated diseases. Previous results indicate that the complex between Extracellular-regulated kinase 3 (ERK3) and Mitogen-Activated Protein Kinase (MAPK)-activated protein kinase 5 (MK5) suppresses energy dissipation and promotes fatty acids (FAs) output in adipose tissue and, therefore promotes obesity and diabetes. However, the therapeutic potential of targeting this complex at the systemic level has not been fully explored. Here we applied a translational approach to target the ERK3/MK5 complex in mice. Importantly, deletion of ERK3 in the whole body or administration of MK5-specific inhibitor protects against obesity and promotes insulin sensitivity. Finally, we show that the expression of ERK3 and MK5 correlates with the degree of obesity and that ERK3/MK5 complex regulates energy dissipation in human adipocytes. Altogether, we demonstrate that ERK3/MK5 complex can be targeted in vivo to preserve metabolic health and combat obesity and diabetes.

Phylogenomic resolution of the root of Panpulmonata, a hyperdiverse radiation of gastropods: new insight into the evolution of air breathing.

Transitions to terrestriality have been associated with major animal radiations including land snails and slugs in Stylommatophora (>20 000 described species), the most successful lineage of 'pulmonates' (a non-monophyletic assemblage of air-breathing gastropods). However, phylogenomic studies have failed to robustly resolve relationships among traditional pulmonates and affiliated marine lineages that comprise clade Panpulmonata (Mollusca, Gastropoda), especially two key taxa: Sacoglossa, a group including photosynthetic sea slugs, and Siphonarioidea, intertidal limpet-like snails with a non-contractile pneumostome (narrow opening to a vascularized pallial cavity). To clarify the evolutionary history of the panpulmonate radiation, we performed phylogenomic analyses on datasets of up to 1160 nuclear protein-coding genes for 110 gastropods, including 40 new transcriptomes for Sacoglossa and Siphonarioidea. All 18 analyses recovered Sacoglossa as the sister group to a clade we named Pneumopulmonata, within which Siphonarioidea was sister to the remaining lineages in most analyses. Comparative modelling indicated shifts to marginal habitat (estuarine, mangrove and intertidal zones) preceded and accelerated the evolution of a pneumostome, present in the pneumopulmonate ancestor along with a one-sided plicate gill. These findings highlight key intermediate stages in the evolution of air-breathing snails, supporting the hypothesis that adaptation to marginal zones played an important role in major sea-to-land transitions.

Diacylglycerol-evoked activation of PKC and PKD isoforms in regulation of glucose and lipid metabolism: a review.

Protein kinase C (PKC) and Protein kinase D (PKD) isoforms can sense diacylglycerol (DAG) generated in the different cellular compartments in various physiological processes. DAG accumulates in multiple organs of the obese subjects, which leads to the disruption of metabolic homeostasis and the development of diabetes as well as associated diseases. Multiple studies proved that aberrant activation of PKCs and PKDs contributes to the development of metabolic diseases. DAG-sensing PKC and PKD isoforms play a crucial role in the regulation of metabolic homeostasis and therefore might serve as targets for the treatment of metabolic disorders such as obesity and diabetes.

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.

Diet-driven ecological radiation and allopatric speciation result in high species diversity in a temperate-cold water marine genus Dendronotus (Gastropoda: Nudibranchia).

While the majority nudibranch clades are more species rich in the tropics, the genus Dendronotus is mainly represented in Arctic and boreal regions. This distribution pattern remains poorly understood. An integrative approach and novel data provided valuable insights into processes driving Dendronotus radiation and speciation. We propose an evolutionary scenario based on molecular phylogenetics and morphological, ecological, ontogenetic data, combined with data on complex geology and paleoclimatology of this region. Estimated phylogenetic relationships based on four molecular markers (COI, 16S, H3 and 28S) shows strong correlation with radular morphology, diet and biogeographical pattern. Ancestral area reconstruction (AAR) provides evidence for a tropical Pacific origin of the genus. Based on AAR and divergence time estimates we conclude that the evolution of Dendronotus has been shaped by different processes: initial migration out of the tropics, diet-driven adaptive radiation in the North Pacific influenced by Miocene climate change, and subsequent allopatric speciation resulting from successive closings of the Bering strait and cooling of the Arctic Ocean during the Pliocene-Pleistocene. At the same time, contemporary amphiboreal species appear to have dispersed into the Atlantic fairly recently.

A biting commentary: Integrating tooth characters with molecular data doubles known species diversity in a lineage of sea slugs that consume "killer algae".

Predicting biotic resistance to highly invasive strains of "killer algae" (Caulerpa spp.) requires understanding the diversity and feeding preferences of native consumers, including sea slugs in family Oxynoidae. Past studies reported low algal host specificity for Oxynoe (6 spp.) and Lobiger (4 spp.), but these taxonomically challenging slugs may represent species complexes of unrecognized specialists that prefer different Caulerpa spp. Here, we assess global diversity of these genera by integrating gene sequences with morphological data from microscopic teeth and internal shells, the only hard parts in these soft-bodied invertebrates. Four delimitation methods applied to datasets comprising mtDNA and/or nuclear alleles yielded up to 16 species hypotheses for samples comprising five nominal taxa, including five highly divergent species in Lobiger and five in Oxynoe. Depending on the analysis, a further four to six species were recovered in the O. antillarum-viridis complex, a clade in which mitochondrial divergence was low and nuclear alleles were shared among lineages. Bayesian species delimitation using only morphological data supported most candidate species, however, and integrative analyses combining morphological and genetic data fully supported all complex members. Collectively, our findings double the recognized biodiversity in Oxynoidae, and illustrate the value of including data from traits that mediate fast-evolving ecological interactions during species delimitation. Preference for Caulerpa spp. and radular tooth characteristics covaried among newly delimited species, highlighting an unappreciated degree of host specialization and coevolution in these taxa that may help predict their role in containing outbreaks of invasive algae.

Inhibition of PCSK9 does not improve lipopolysaccharide-induced mortality in mice.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a secreted protein that targets LDL receptors (LDLRs) for degradation in liver. Blocking the interaction of PCSK9 with the LDLR potently reduces plasma LDL cholesterol levels and cardiovascular events. Recently, it has been suggested that inhibition of PCSK9 might also improve outcomes in mice and humans with sepsis, possibly by increasing LDLR-mediated clearance of endotoxins. Sepsis is a complication of a severe microbial infection that has shared pathways with lipid metabolism. Here, we tested whether anti-PCSK9 antibodies prevent death from lipopolysaccharide (LPS)-induced endotoxemia. Mice were administered PCSK9 antibodies prior to, or shortly after, injecting LPS. In both scenarios, the administration of PCSK9 antibodies did not alter endotoxemia-induced mortality. Afterward, we determined whether the complete absence of PCSK9 improved endotoxemia-induced mortality in mice with the germ-line deletion of Pcsk9 Similarly, PCSK9 knockout mice were not protected from LPS-induced death. To determine whether low LDLR expression increased LPS-induced mortality, Ldlr-/- mice and PCSK9 transgenic mice were studied after injection of LPS. Endotoxemia-induced mortality was not altered in either mouse model. In a human cohort, we observed no correlation between plasma inflammation markers with total cholesterol levels, LDL cholesterol, and PCSK9. Combined, our data demonstrate that PCSK9 inhibition provides no protection from LPS-induced mortality in mice.

Prey preference follows phylogeny: evolutionary dietary patterns within the marine gastropod group Cladobranchia (Gastropoda: Heterobranchia: Nudibranchia).

BACKGROUND: The impact of predator-prey interactions on the evolution of many marine invertebrates is poorly understood. Since barriers to genetic exchange are less obvious in the marine realm than in terrestrial or freshwater systems, non-allopatric divergence may play a fundamental role in the generation of biodiversity. In this context, shifts between major prey types could constitute important factors explaining the biodiversity of marine taxa, particularly in groups with highly specialized diets. However, the scarcity of marine specialized consumers for which reliable phylogenies exist hampers attempts to test the role of trophic specialization in evolution. In this study, RNA-Seq data is used to produce a phylogeny of Cladobranchia, a group of marine invertebrates that feed on a diverse array of prey taxa but mostly specialize on cnidarians. The broad range of prey type preferences allegedly present in two major groups within Cladobranchia suggest that prey type shifts are relatively common over evolutionary timescales. RESULTS: In the present study, we generated a well-supported phylogeny of the major lineages within Cladobranchia using RNA-Seq data, and used ancestral state reconstruction analyses to better understand the evolution of prey preference. These analyses answered several fundamental questions regarding the evolutionary relationships within Cladobranchia, including support for a clade of species from Arminidae as sister to Tritoniidae (which both preferentially prey on Octocorallia). Ancestral state reconstruction analyses supported a cladobranchian ancestor with a preference for Hydrozoa and show that the few transitions identified only occur from lineages that prey on Hydrozoa to those that feed on other types of prey. CONCLUSIONS: There is strong phylogenetic correlation with prey preference within Cladobranchia, suggesting that prey type specialization within this group has inertia. Shifts between different types of prey have occurred rarely throughout the evolution of Cladobranchia, indicating that this may not have been an important driver of the diversity within this group.

Species Selection Favors Dispersive Life Histories in Sea Slugs, but Higher Per-Offspring Investment Drives Shifts to Short-Lived Larvae.

For 40 years, paleontological studies of marine gastropods have suggested that species selection favors lineages with short-lived (lecithotrophic) larvae, which are less dispersive than long-lived (planktotrophic) larvae. Although lecithotrophs appeared to speciate more often and accumulate over time in some groups, lecithotrophy also increased extinction rates, and tests for state-dependent diversification were never performed. Molecular phylogenies of diverse groups instead suggested lecithotrophs accumulate without diversifying due to frequent, unidirectional character change. Although lecithotrophy has repeatedly originated in most phyla, no adult trait has been correlated with shifts in larval type. Thus, both the evolutionary origins of lecithotrophy and its consequences for patterns of species richness remain poorly understood. Here, we test hypothesized links between development mode and evolutionary rates using likelihood-based methods and a phylogeny of 202 species of gastropod molluscs in Sacoglossa, a clade of herbivorous sea slugs. Evolutionary quantitative genetics modeling and stochastic character mapping supported 27 origins of lecithotrophy. Tests for correlated evolution revealed lecithotrophy evolved more often in lineages investing in extra-embryonic yolk, the first adult trait associated with shifts in development mode across a group. However, contrary to predictions from paleontological studies, species selection actually favored planktotrophy; most extant lecithotrophs originated through recent character change, and did not subsequently diversify. Increased offspring provisioning in planktotrophs thus favored shifts to short-lived larvae, which led to short-lived lineages over macroevolutionary time scales. These findings challenge long-standing assumptions about the effects of alternative life histories in the sea. Species selection can explain the long-term persistence of planktotrophy, the ancestral state in most clades, despite frequent transitions to lecithotrophy.

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.

A cryptic radiation of Caribbean sea slugs revealed by integrative analysis: Cyerce 'antillensis' (Sacoglossa: Caliphyllidae) is six distinct species.

Integrative studies have revealed cryptic radiations in several Caribbean lineages of heterobranch sea slugs, raising questions about the evolutionary mechanisms that promote speciation within the tropical Western Atlantic. Cyerce Bergh, 1871 is a genus comprising 12 named species in the family Caliphyllidae that lack the photosynthetic ability of other sacoglossans but are noted for vibrant colours on the large cerata (dorsal leaf-like appendages) that characterize many species. Two species are widely reported from the Caribbean: Cyerce cristallina (Trinchese, 1881) and Cyerce antillensis Engel, 1927. Here, we present an integrative assessment of diversity in Caribbean Cyerce. Four methods of molecular species delimitation supported seven species in samples from the Caribbean and adjacent subtropical Western Atlantic. Six delimited species formed a monophyletic lineage in phylogenetic analyses but were > 9% divergent at the barcoding COI locus and could be differentiated using ecological, reproductive and/or morphological traits. We redescribe C. antillensis, a senior synonym for the poorly known Cyerce habanensis Ortea & Templado, 1988, and describe five new species. Evolutionary shifts in algal host use, penial armature and larval life history might have acted synergistically to promote the rapid divergence of endemic species with restricted distributions in this radiation, substantially increasing global diversity of the genus.

Parallel changes in genital morphology delineate cryptic diversification of planktonic nudibranchs.

The relative roles of geographical and non-geographical barriers in the genesis of genetic isolation are highly debated in evolutionary biology, yet knowing how speciation occurs is essential to our understanding of biodiversity. In the open ocean, differentiating between the two is particularly difficult, because of the high levels of gene flow found in pelagic communities. Here, we use molecular phylogenetics to test the hypothesis that geography is the primary isolating mechanism in a clade of pelagic nudibranchs, Glaucinae. Our results contradict allopatric expectations: the cosmopolitan Glaucus atlanticus is panmictic, whereas the Indo-Pacific Glaucus marginatus contains two pairs of cryptic species with overlapping distributions. Within the G. marginatus species complex, a parallel reproductive change has occurred in each cryptic species pair: the loss of a bursa copulatrix. Available G. marginatus data are most consistent with non-geographical speciation events, but we cannot rule out the possibility of allopatric speciation, followed by iterative range extension and secondary overlap. Irrespective of ancestral range distributions, our results implicate a central role for reproductive character differentiation in glaucinin speciation-a novel result in a planktonic system.

The genus Pupa Röding, 1798 (Mollusca, Gastropoda, Acteonidae) in New Caledonia with notes on Recent species.

The study of newly collected, live specimens of Pupa (Acteonidae) from New Caledonia and French Polynesia, revealed the presence of six distinct species in this region, including an undescribed species. All these species are re-described and/or named using molecular and morphological evidence as well as a review of the literature and examination of photographs of the type material of described species. Moreover, a review of the literature and type material suggests the existence of six additional species from other geographic regions across the Indo-Pacific. Illustrations of all these species are provided as well as remarks on possible synonymies. This study is the first species-level review of this group using modern taxonomic techniques.

Seven new "cryptic" species of Discodorididae (Mollusca, Gastropoda, Nudibranchia) from New Caledonia.

The study of a well-preserved collection of discodorid nudibranchs collected in Koumac, New Caledonia, revealed the presence of seven species new to science belonging to the genera Atagema, Jorunna, Rostanga, and Sclerodoris, although some of the generic assignments are tentative as the phylogeny of Discodorididae remains unresolved. Moreover, a poorly known species of Atagema originally described from New Caledonia is re-described and the presence of Sclerodoristuberculata in New Caledonia is confirmed with molecular data. All the species described herein are highly cryptic on their food source and in the context of the present study the term "cryptic" is used to denote such species. This paper highlights the importance of comprehensive collecting efforts to identify and document well-camouflaged taxa.