The venom contains toxins that have evolved convergently in other venomous lineages

Venom systems have evolved on multiple occasions across the animal kingdom, and they can act as key adaptations to protect animals from predators []. Consequently, venomous animals serve as models for a rich source of mimicry types, as non-venomous species benefit from reductions in predation risk by mimicking the coloration, body shape, and/or movement of toxic counterparts []. The frequent evolution of such deceitful imitations provides notable examples of phenotypic convergence and are often invoked as classic exemplars of evolution by natural selection. Here, we investigate the evolution of fangs, venom, and mimetic relationships in reef fishes from the tribe Nemophini (fangblennies). Comparative morphological analyses reveal that enlarged canine teeth (fangs) originated at the base of the Nemophini radiation and have enabled a micropredatory feeding strategy in non-venomous Plagiotremus spp. Subsequently, the evolution of deep anterior grooves and their coupling to venom secretory tissue provide Meiacanthus spp. with toxic venom that they effectively employ for defense. We find that fangblenny venom contains a number of toxic components that have been independently recruited into other animal venoms, some of which cause toxicity via interactions with opioid receptors, and result in a multifunctional biochemical phenotype that exerts potent hypotensive effects. The evolution of fangblenny venom has seemingly led to phenotypic convergence via the formation of a diverse array of mimetic relationships that provide protective (Batesian mimicry) and predatory (aggressive mimicry) benefits to other fishes []. Our results further our understanding of how novel morphological and biochemical adaptations stimulate ecological interactions in the natural world.

Results and Discussion

2 Moland E.

Eagle J.V.

Jones G.P. Ecology and evolution of mimicry in coral reef fishes. 6 Cheney K.L. Multiple selective pressures apply to a coral reef fish mimic: a case of Batesian-aggressive mimicry. 7 Smith-Vaniz W.

Satapoomin U.

Allen G. Meiacanthus urostigma, a new fangblenny from the northeastern Indian Ocean, with discussion and examples of mimicry in species of Meiacanthus (Teleostei: Blenniidae: Nemophini). 8 Cheney K.L. Interspecific relationships in Blennies. 2 Moland E.

Eagle J.V.

Jones G.P. Ecology and evolution of mimicry in coral reef fishes. 6 Cheney K.L. Multiple selective pressures apply to a coral reef fish mimic: a case of Batesian-aggressive mimicry. 2 Moland E.

Eagle J.V.

Jones G.P. Ecology and evolution of mimicry in coral reef fishes. Figure 1 Examples of Mimetic Relationships Involving Meiacanthus and the Phylogenetic Relationship of Fangblennies Show full caption 2 Moland E.

Eagle J.V.

Jones G.P. Ecology and evolution of mimicry in coral reef fishes. 6 Cheney K.L. Multiple selective pressures apply to a coral reef fish mimic: a case of Batesian-aggressive mimicry. 7 Smith-Vaniz W.

Satapoomin U.

Allen G. Meiacanthus urostigma, a new fangblenny from the northeastern Indian Ocean, with discussion and examples of mimicry in species of Meiacanthus (Teleostei: Blenniidae: Nemophini). (A) Examples of venomous Meiacanthus fangblennies (red circles) serving as models in mimetic relationships with other non-venomous fangblennies (orange circles) and non-fangblenny species (black circles). These relationships include Batesian and aggressive mimicry []. Photos courtesy of Rudie Kuiter, Arthur Bos, Richard Smith (© Richard Smith | OceanRealmImages.com ), and K.L.C. ∗) indicate genera that contain at least one member known to mimic Meiacanthus fangblennies [ 2 Moland E.

Eagle J.V.

Jones G.P. Ecology and evolution of mimicry in coral reef fishes. (B) Schematic topology of the relationship between different genera found in the tribe Nemophini (see also Figure S1 and Table S1 ) and the single most parsimonious timings for the origin of enlarged canine teeth (fangs) and venom. Numbers at nodes represent Bayesian posterior probabilities, and asterisks () indicate genera that contain at least one member known to mimic Meiacanthus fangblennies []. Fishes of the tribe Nemophini, known as fangblennies, represent a unique system for studying the adaptations underpinning the formation of mimetic relationships. This tribe consists of five genera: the venomous genus Meiacanthus and four non-venomous genera, of which Plagiotremus and Petroscirtes contain species that mimic the aposematic coloration and behavior of Meiacanthus [] ( Figure 1 A). A number of fangblenny models are mimicked by multiple sympatric fish species (see [] for a thorough overview), and although Batesian mimicry prevails in all such relationships, some members of the genus Plagiotremus also use mimicry in an aggressive manner, to gain access to larger fishes to feed on their scales and fins [] ( Figure 1 A). While other fangblennies (e.g., Aspidontus taeniatus) are known to mimic non-Meiacanthus models, such as the cleaner wrasse Labroides dimidiatus [], for the purposes of this study we focus only on mimetic relationships in which venomous Meiacanthus fangblennies are the models.

9 Hundt P.J.

Iglésias S.P.

Hoey A.S.

Simons A.M. A multilocus molecular phylogeny of combtooth blennies (Percomorpha: Blennioidei: Blenniidae): multiple invasions of intertidal habitats. 9 Hundt P.J.

Iglésias S.P.

Hoey A.S.

Simons A.M. A multilocus molecular phylogeny of combtooth blennies (Percomorpha: Blennioidei: Blenniidae): multiple invasions of intertidal habitats. We first reconstructed the evolutionary relationship of fangblennies by sequencing five molecular markers from representative Nemophini species ( Table S1 ). Our concatenated dataset (n = 36; 2,691 bp) produces a strongly supported tree topology ( Figure S1 ) largely consistent with that of Hundt et al. []. However, in our tree the venomous genus Meiacanthus forms a strongly supported sister clade to a monophyletic group containing the genera Aspidontus and Petroscirtes ( Figure 1 B), whereas in Hundt et al. [] Meiacanthus was found sister to Plagiotremus and Xiphasia without strong support. In our analysis, the remaining genera, Xiphasia and Plagiotremus, form a monophyletic group sister to that of Meiacanthus, Aspidontus and Petroscirtes.

Figure 2 Oral Morphology of the Canines and Venom System of Fangblennies (Tribe Nemophini) Show full caption Left column: lateral view of micro-CT scans. Red lines indicate the base of enlarged canines; yellow lines labeled TC indicate the tip of the canine. Middle column: rostral view of the lower jaw by stacking microscope. Right column: histology sections showing the oral cavity at 2× zoom. Annotations: C, canine; V, venom gland (Meiacanthus grammistes only). Note the smaller comparative fang size in the outgroup species Omobranchus anolius (tribe Omobranchiini). See also Figure S2 Figure 3 Morphology of the Meiacanthus Venom System Show full caption (A and B) Lateral view of micro-CT scans of M. grammistes showing the size of the enlarged venom-transmitting fangs (colored red) in mouth closed (A) and mouth open (B) positions (see also Figure S1 ). (C) 20× zoomed histological section of M. grammistes showing the anterior region of the venom gland with deep purple cells, a canine tooth, and enveloping connective tissue. Annotations in (C) and (D): C, canine; V, venom gland; IS, integumentary sheath; RC, replacement canine. (D) 20× zoomed histological section of M. reticulatus showing a depleted venom gland (posterior portion). (E and F) 3D reconstructions of histological sections from M. grammistes (E) and M. reticulatus (F), showing the venom glands (green) surrounding the base of the canine tooth (red) and entering the anterior groove of the canine. Note that the canine reconstructions are incomplete. We next used micro-computed tomography (microCT) scanning, stacking microscopy, and histology to provide a comprehensive overview of the oral morphology of fangblennies and their close relatives. Our comparative morphological analyses demonstrate that all fangblennies have enlarged canine teeth (fangs) on their lower jaw and buccal epithelium surface areas in comparison with their relatives ( Figures 2 3 A, 3 B, S1 , and S2 ). Histological analyses reveal that all members of the Nemophini have hollow fangs, and while Meiacanthus and Petroscirtes both have a maxillary sheath to accommodate the enlarged teeth, only Meiacanthus spp. possess anterior grooves for the transmission of venom. Similarly, only Meiacanthus spp. have venom glands ( Figures 2 3 C, and 3D). Three-dimensional reconstructions of histological sections of M. grammistes and M. reticulatus venom glands show that they surround the base of the fangs posteriorly and enter the anterior groove, an arrangement which presumably facilitates the transmission of venom from the venom gland into the target during biting ( Figures 3 E and 3F).

10 Fry B.G.

Sunagar K.

Casewell N.R.

Kochva E.

Roelants K.

Scheib H.

Wüster W.

Vidal N.

Young B.

Burbrink F.

et al. The origin and evolution of the Toxicofera reptile venom system. Overlaying the presence or absence of (1) enlarged canine teeth and (2) venom glands onto the species phylogeny revealed a single most parsimonious explanation for the origin of each of these characters, namely, the combined presence of enlarged canines at the base of the tribe Nemophini, and venom glands at the base of the Meiacanthus radiation ( Figure 1 B). Therefore, unlike venomous snakes where the chemical weapon preceded the refined venom delivery dentition [], fangblennies evolved mechanical structures amenable for venom delivery prior to the origin of their toxic secretions.

11 Fishelson L. Histology and ultrastructure of the recently found buccal toxic gland in the fish Meiacanthus nigrolineatus (Blenniidae). 12 Martini F. The venom apparatus of the fanged blenny, Meiacanthus atrodorsalis. 13 Losey G.S. Predation protection in the poison-fang blenny, Meiacanthus atrodorsalis, and its mimics, Ecsenius bicolor and Runula laudandus (Blenniidae). 14 Losey G.S. Meiacanthus atrodorsalis: Field evidence of predation protection. 13 Losey G.S. Predation protection in the poison-fang blenny, Meiacanthus atrodorsalis, and its mimics, Ecsenius bicolor and Runula laudandus (Blenniidae). 13 Losey G.S. Predation protection in the poison-fang blenny, Meiacanthus atrodorsalis, and its mimics, Ecsenius bicolor and Runula laudandus (Blenniidae). Little is known about the fangblenny venom system, other than that enlarged canine teeth deliver venom into aggressors to prevent ingestion []. The defensive nature of the venom is perhaps best evidenced by observations of multiple predatory fishes ingesting M. atrodorsalis before “quivering of the head with distention of the jaws and operculi” occurred, followed by the fangblenny emerging from the mouth unharmed []. Furthermore, feeding experiments with M. atrodorsalis demonstrated that when their canine fangs were removed, fangblennies were readily consumed by predatory fish, whereas fangblennies with fangs intact were expelled and avoided in subsequent encounters [].

15 Smith W.L.

Stern J.H.

Girard M.G.

Davis M.P. Evolution of venomous cartilaginous and ray-finned fishes. 15 Smith W.L.

Stern J.H.

Girard M.G.

Davis M.P. Evolution of venomous cartilaginous and ray-finned fishes. 16 Bertelsen E.

Nielsen J. The deep sea eel family Monognathidae (Pisces, Anguilliformes). The oral venom system of Meiacanthus is exceptional among teleosts, as venom is typically delivered via the mechanical rupture of secretory cells associated with dorsal and/or opercular spines []. Indeed, the use of an oral venom system exclusively for defensive purposes is unusual in the animal kingdom. We suggest that the absence of large fin spines amenable for effective venom delivery in blenny ancestors, coupled with the enlargement of canine fangs, has facilitated the evolution of oral venom observed in Meiacanthus. Eels of the genus Monognathus are the only other fishes thought to have a venomous bite [], although they are thought to use their venom primarily for predatory purposes. Nonetheless, we note that ancestors of these fishes also lack large fin spines suitable for defensive purposes [], suggesting an element of constraint.

2 (PLA 2 ), proenkephalin, and neuropeptide Y ( Figure 4 The Bioactivity of Venom from the Fangblenny Meiacanthus grammistes Show full caption (A) Reduced SDS-PAGE profile of extracted venom. 2 -specific fluorescent substrate. Venom PLA 2 activity is comparable to that of the snakes Parias hageni (Hagen’s pit viper) and Tropidolaemus wagleri (Wagler’s pit viper) (∗p ≤ 0.01; unpaired t test). See also 2 . (B) Fangblenny venom (0.5 and 1.0 μg) exhibits dose-dependent phospholipase activity via the cleavage of a PLA-specific fluorescent substrate. Venom PLAactivity is comparable to that of the snakes Parias hageni (Hagen’s pit viper) and Tropidolaemus wagleri (Wagler’s pit viper) (p ≤ 0.01; unpaired t test). See also Figure S3 and Table S2 for information on fangblenny PLA ∗∗∗∗p ≤ 0.0001, ∗∗∗p ≤ 0.001, ∗∗p ≤ 0.01, ∗p ≤ 0.05; one-way ANOVA with a Dunnett post-test) in HEK cells expressing δ-subtype opioid receptors (C), which was blocked by the non-selective opioid receptor antagonist naloxone (50 μM) (p ≤ 0.0001, two-way ANOVA with a Sidak post-test) (D). See also (C and D) Fangblenny venom (10.0, 1.0, and 0.1 μg/ml) significantly inhibits cAMP production (p ≤ 0.0001,p ≤ 0.001,p ≤ 0.01,p ≤ 0.05; one-way ANOVA with a Dunnett post-test) in HEK cells expressing δ-subtype opioid receptors (C), which was blocked by the non-selective opioid receptor antagonist naloxone (50 μM) (p ≤ 0.0001, two-way ANOVA with a Sidak post-test) (D). See also Figure S4 (E and F) Venom (50 μg protein/kg i.v.; n = 3) causes a single depressor effect on the mean arterial blood pressure of the anaesthetized rat (E) but has no significant effect on heart rate (50 μg protein/kg i.v.; n = 3) (F). (G and H) Fangblenny venom (2.5 μg protein/ml, n = 4) induces a significant decrease (∗p ≤ 0.01; unpaired t test) in the indirect twitches in the CBCNM preparation over 60 min (G) but has no effect on the responses to the exogenous agonists acetylcholine (ACh; 1 mM), carbachol (CCh; 20 μM), and potassium chloride (KCl; 40 mM) (H). All data points represent mean ± SEM. To investigate the toxin composition of fangblenny venom, we constructed transcriptomes from the venom gland of M. atrodorsalis and tissue from the corresponding location in the non-venomous species Plagiotremus tapeinosoma, and we performed proteomic analyses on venom extracted from M. grammistes ( Figure 4 A). Putative toxins were identified by their abundant expression in the venom gland transcriptome and their absence, or low-level expression, in the control transcriptome, coupled with their detection in secreted venom. While many of the proteomic matches were to genes encoding constitutive housekeeping proteins, we found three toxin types, none of which have been previously reported from fish venom, that exhibit characteristics consistent with venom-specific roles: group X phospholipases A(PLA), proenkephalin, and neuropeptide Y ( Figure S3 ).

2 s were detected in both transcriptomes, the expression level observed in the P. tapeinosoma control transcriptome was extremely low (0.04%). In contrast, both PLA 2 and neuropeptide Y were heavily expressed in the venom gland transcriptome, with single contigs representing the third and fourth most abundant annotated contigs (1.30% and 1.00% respectively; th most abundant). Proenkephalin and neuropeptide Y were both found to be expressed in the M. atrodorsalis venom gland transcriptome, identified proteomically in M. grammistes venom, and completely absent from the P. tapeinosoma control transcriptome, strongly suggesting venom-specific roles. Although genes encoding group X PLAs were detected in both transcriptomes, the expression level observed in the P. tapeinosoma control transcriptome was extremely low (0.04%). In contrast, both PLAand neuropeptide Y were heavily expressed in the venom gland transcriptome, with single contigs representing the third and fourth most abundant annotated contigs (1.30% and 1.00% respectively; Table S2 ), whereas proenkephalin exhibited a more moderate expression level (0.15%; 69most abundant).

2 s hydrolyze ester bonds of glycerophospholipids to produce fatty acids and lysophospholipids, and they are common constituents in animal venoms (e.g., bees, scorpions, snakes [ 17 Six D.A.

Dennis E.A. The expanding superfamily of phospholipase A(2) enzymes: classification and characterization. 2 s has not been previously described from any venom, they are known to promote inflammatory pathology [ 18 Hanasaki K.

Arita H. Biological Functions of Group X secretory PLA2. 19 Watanabe K.

Fujioka D.

Saito Y.

Nakamura T.

Obata J.E.

Kawabata K.

Watanabe Y.

Mishina H.

Tamaru S.

Hanasaki K.

Kugiyama K. Group X secretory PLA2 in neutrophils plays a pathogenic role in abdominal aortic aneurysms in mice. 2 activity and causes dose-dependent cleavage of a PLA 2 -sepecific substrate ( 2 activity of fangblenny venom with those of two viperid snakes (Tropidolaemus wagleri and Parias hageni) known to have venom PLA 2 s [ 20 Wang Y.M.

Liew Y.F.

Chang K.Y.

Tsai I.H. Purification and characterization of the venom phospholipases A2 from Asian monotypic crotalinae snakes. 21 Malhotra A.

Creer S.

Harris J.B.

Thorpe R.S. The importance of being genomic: Non-coding and coding sequences suggest different models of toxin multi-gene family evolution. 2 is likely a biologically relevant venom toxin. Secreted PLAs hydrolyze ester bonds of glycerophospholipids to produce fatty acids and lysophospholipids, and they are common constituents in animal venoms (e.g., bees, scorpions, snakes []). Although the group X class of PLAs has not been previously described from any venom, they are known to promote inflammatory pathology []. Using a fluorescence in vitro enzyme assay, we demonstrated that fangblenny venom exhibits considerable PLAactivity and causes dose-dependent cleavage of a PLA-sepecific substrate ( Figure 4 B). To put these results into biological context, we compared the PLAactivity of fangblenny venom with those of two viperid snakes (Tropidolaemus wagleri and Parias hageni) known to have venom PLAs []. We found comparable levels of substrate cleavage between the different venoms ( Figure 4 B), suggesting that fangblenny PLAis likely a biologically relevant venom toxin.

22 Lord J.A.

Waterfield A.A.

Hughes J.

Kosterlitz H.W. Endogenous opioid peptides: multiple agonists and receptors. 23 Moore 3rd, R.H.

Dowling D.A. Effects of intravenously administered Leu- or Met-enkephalin on arterial blood pressure. 24 Plotnikoff N.P.

Faith R.E.

Murgo A.J.

Herberman R.B.

Good R.A. Methionine enkephalin: a new cytokine--human studies. 25 Zhang Y.

Xu J.

Wang Z.

Zhang X.

Liang X.

Civelli O. BmK-YA, an enkephalin-like peptide in scorpion venom. Proenkephalin encodes multiple 5-aa peptides known as met-enkephalins, which are endogenous opioid hormones that function by interacting with opioid receptors and induce transient analgesia, hypotension, and inflammatory responses []. To test for opioid activity, we screened fangblenny venom against human embryonic kidney 293 (HEK) cells expressing μ-, κ-, and δ-subtype opioid receptors. The δ and μ, but not κ, displayed significant inhibition of cAMP production in the presence of fangblenny venom, with the greatest reduction seen with the δ cell line ( Figures 4 C and S4 ). To confirm that the inhibition of cAMP observed in the δ and μ cells was mediated through the opioid receptors, we used naloxone, a non-selective opioid receptor antagonist, to block receptor activity. We find that the inhibited production of cAMP caused by fangblenny venom was largely blocked by naloxone in cells expressing δ-subtype opioid receptors, but not in those expressing μ ( Figures 4 D and S4 ). These results demonstrate that, in a similar manner to those identified from the venom of the scorpion B. martensii [], enkephalin peptides found in Meiacanthus induce physiological effects via their interaction with δ-subtype opioid receptors.

26 Wu X.

Shao X.

Guo Z.-Y.

Chi C.-W. Identification of neuropeptide Y-like conopeptides from the venom of Conus betulinus. 27 Tatemoto K. Neuropeptide Y: history and overview. 23 Moore 3rd, R.H.

Dowling D.A. Effects of intravenously administered Leu- or Met-enkephalin on arterial blood pressure. 28 Fuxe K.

Agnati L.F.

Härfstrand A.

Zini I.

Tatemoto K.

Pich E.M.

Hökfelt T.

Mutt V.

Terenius L. Central administration of neuropeptide Y induces hypotension bradypnea and EEG synchronization in the rat. Neuropeptide Y provides another example of the same starting substrate being convergently utilized for a role in animal venom, having previously been identified in the cone snail Conus betulinus []. These peptides are relatively well conserved, are found widely distributed in nervous systems, and are crucial for the regulation of cardiovascular processes such as blood pressure []. Consequently, we assessed the bioactivity of fangblenny venom in in vivo cardiovascular assays. We found that M. grammistes venom caused a marked depressor effect on the mean arterial pressure of anaesthetized rats ( Figure 4 E), consisting of a transient depressor response followed by a sustained depressor response and resulting in a maximal decrease of 37% (±5%). Despite this potent hypotensive bioactivity, we found that M. grammistes venom had no significant effect on the heart rate of anaesthetized rats ( Figure 4 F). These results are highly suggestive in regards to neuropeptide Y and enkephalins: both peptides, detected here in fangblenny venom, have previously been demonstrated to significantly reduce blood pressure in vivo, without having any discernible effect on heart rate [].

29 Sivan G. Fish venom: pharmacological features and biological significance. 2 s found in snake venom have previously been described to cause neurotoxicity [ 30 Rigoni M.

Schiavo G.

Weston A.E.

Caccin P.

Allegrini F.

Pennuto M.

Valtorta F.

Montecucco C.

Rossetto O. Snake presynaptic neurotoxins with phospholipase A2 activity induce punctate swellings of neurites and exocytosis of synaptic vesicles. 31 Silva A.

Kuruppu S.

Othman I.

Goode R.J.A.

Hodgson W.C.

Isbister G.K. Neurotoxicity in Sri Lankan Russell’s viper (Daboia russelii) envenoming is primarily due to U1-viperitoxin-Dr1a, a pre-synaptic neurotoxin. Given prior reports of some fish venoms exhibiting neuronal bioactivity [], we next tested the neurotoxic effect of fangblenny venom in the chick biventer cervicis nerve muscle (CBCNM) preparation. M. grammistes venom exhibited a weak neurotoxic effect by causing a significant decrease in indirect twitches of the CBCNM over 60 min ( Figure 4 G) but did not inhibit responses to exogenous acetylcholine, carbachol, or potassium chloride, indicating a lack of activity at skeletal muscle nicotinic receptors ( Figure 4 H). It remains unclear which component(s) in fangblenny venom are responsible for causing this neurotoxic bioactivity, although we note that some PLAs found in snake venom have previously been described to cause neurotoxicity [].

29 Sivan G. Fish venom: pharmacological features and biological significance. 32 Church J.E.

Hodgson W.C. The pharmacological activity of fish venoms. 1 Casewell N.R.

Wüster W.

Vonk F.J.

Harrison R.A.

Fry B.G. Complex cocktails: the evolutionary novelty of venoms. 33 Harris R.J.

Arbuckle K. Tempo and mode of the evolution of venom and poison in Tetrapods. 13 Losey G.S. Predation protection in the poison-fang blenny, Meiacanthus atrodorsalis, and its mimics, Ecsenius bicolor and Runula laudandus (Blenniidae). 2 s), and perhaps also proinflammatory (PLA 2 s and/or enkephalins). The combination of these venom bioactivities therefore appears sufficient to effectively confer distastefulness and learned avoidance behaviors in piscine predators [ 13 Losey G.S. Predation protection in the poison-fang blenny, Meiacanthus atrodorsalis, and its mimics, Ecsenius bicolor and Runula laudandus (Blenniidae). Spine-delivered fish venoms are typically notoriously painful, and the primary pathology observed following envenomings is pain disproportionate to the wound []. Considering that such fish use their venom for defensive purposes, pain is an effective tool for deterring predators and invoking learned avoidance responses. Consequently, the use of pain-inducing molecules has evolved convergently in many other venomous lineages that use venom for defensive purposes []. However, when we subcutaneously injected fangblenny venom into the hindpaw of anaesthetized mice, we observed no evidence of behavioral characteristics consistent with pain (paw lifts, licks, shakes, and flinches) and no difference between envenomed and control animals. These data correlate with some reports of human bites by fangblennies being relatively painless []. Therefore, in contrast to the spine-delivered venom employed by most venomous fish, we find that the oral venom of the fangblenny does not induce immediate, substantial pain to mammals. While species-specific nociceptive effects are possible, our data suggest that this defensive venom is surprisingly multifunctional, being markedly hypotensive (via neuropeptide Y and/or enkephalins), weakly neurotoxic (unknown components, possibly PLAs), and perhaps also proinflammatory (PLAs and/or enkephalins). The combination of these venom bioactivities therefore appears sufficient to effectively confer distastefulness and learned avoidance behaviors in piscine predators [], perhaps irrespective of any potent nociceptive effect. Indeed, the pronounced hypotensive effects induced by venom peptides seem highly likely to affect the coordination and/or swim performance of envenomed fishes and therefore likely confer a fitness advantage to the fangblenny by facilitating escape from predators.

2 Moland E.

Eagle J.V.

Jones G.P. Ecology and evolution of mimicry in coral reef fishes. 6 Cheney K.L. Multiple selective pressures apply to a coral reef fish mimic: a case of Batesian-aggressive mimicry. 7 Smith-Vaniz W.

Satapoomin U.

Allen G. Meiacanthus urostigma, a new fangblenny from the northeastern Indian Ocean, with discussion and examples of mimicry in species of Meiacanthus (Teleostei: Blenniidae: Nemophini). 34 Cheney K.L.

Marshall N.J. Mimicry in coral reef fish: how accurate is this deception in terms of color and luminance?. 35 Smith-Vaniz W. The Saber-Toothed Blennies, Tribe Nemophini (Pisces: Blenniidae). 36 Johnson M.L.

Hull S.L. Interactions between fangblennies (Plagiotremus rhinorhynchus) and their potential victims: fooling the model rather than the client?. 2 Moland E.

Eagle J.V.

Jones G.P. Ecology and evolution of mimicry in coral reef fishes. 6 Cheney K.L. Multiple selective pressures apply to a coral reef fish mimic: a case of Batesian-aggressive mimicry. The evolution of venom in Meiacanthus fangblennies appears likely to have been a contributing factor to many other non-venomous fish coevolving similar aposematic color patterns and swimming behaviors, thus becoming Batesian mimics and benefiting from reduced predation pressures []. These putative mimics include other fangblennies (e.g., Petroscirtes breviceps and Plagiotremus spp.) and a variety of other distantly related fish (e.g., the combtooth blenny Escenius gravieri and the cardinalfish Cheliodipterus nigrotaeniatus) ( Figure 1 A). Moreover, the evolution of enlarged fangs in the tribe Nemophini appears to have also stimulated a unique micropredatory feeding strategy in the genus Plagiotremus as, to our knowledge, all species in this genus feed by attacking larger reef fishes to access dermal tissue, scales, mucus, and fins []. For a number of species, micropredation is facilitated by resembling venomous Meiacanthus fangblennies—mimicry provides increased access to these resources, and thus interactions between Meiacanthus and Plagiotremus represent one of the few described examples of Batesian-aggressive mimicry [].