Aneta Arct, Szymon M. Drobniak, Edyta Podmokła, Lars Gustafson, Mariusz Cichoń
Benefits of extra-pair mating may depend on environmental conditions—an experimental study in the blue tit (Cyanistes caeruleus)
Behavioral Ecology and Sociobiology July 2013
Extra-pair mating constitutes a relatively common reproductive strategy in many socially monogamous bird species. This strategy may considerably improve reproductive success of males, but female benefits from extra-pair matings still remain unclear and empirical evidence is scarce. This may be because genetic benefits of extra-pair mating are not always revealed. It is possible that they are shown only in unfavourable environmental conditions and hence problems arise with detecting differences between within- and extra-pair offspring whose performance is measured under favourable conditions. In order to test this prediction, we manipulated environmental conditions by altering brood sizes of blue tits and compared phenotypic characteristics of within- and extra-pair offspring in mixed-paternity broods. We found that extra-pair young exhibited a higher response to phytohemagglutinin in comparison to within-pair young, but this was only observed among nestlings from experimentally enlarged broods. These results indicate that genetic benefits may interact with the environment, and thus benefits of extra-pair mating are likely to become visible only when conditions are relatively unfavourable.
Gen Del Raye, Salvador J. Jorgensen, Kira Krumhansl, Juan M. Ezcurra, and Barbara A. Block
Travelling light: white sharks (Carcharodon carcharias) rely on body lipid stores to power ocean-basin scale migration
Proc. R. Soc. B September 7, 2013 280 1766 20130836; doi:10.1098/rspb.2013.0836 1471-2954
Many species undertake long-distance annual migrations between foraging and reproductive areas. Such migrants depend on the efficient packaging, storage and utilization of energy to succeed. A diverse assemblage of organisms accomplishes this through the use of lipid reserves; yet, it remains unclear whether the migrations of elasmobranchs, which include the largest gill breathers on Earth, depend on such a mechanism. We examine depth records from pop-up satellite archival tags to discern changes in buoyancy as a proxy for energy storage in Eastern Pacific white sharks, and assess whether lipid depletion fuels long-distance (approx. 4000 km) migrations. We develop new algorithms to assess body condition, buoyancy and drift rate during drift dives and validate the techniques using a captive white shark. In the wild, we document a consistent increase in drift rate over the course of all migrations, indicating a decrease in buoyancy caused by the depletion of lipid reserves. These results comprise, to our knowledge, the first assessment of energy storage and budgeting in migrating sharks. The methods provide a basis for further insights into using electronic tags to reveal the energetic strategies of a wide range of elasmobranchs.
Scott D. Sampson, Eric K. Lund, Mark A. Loewen, Andrew A. Farke, and Katherine E. Clayton
A remarkable short-snouted horned dinosaur from the Late Cretaceous (late Campanian) of southern Laramidia
Proc. R. Soc. B September 7, 2013 280 1766 20131186; doi:10.1098/rspb.2013.1186 1471-2954
The fossil record of centrosaurine ceratopsids is largely restricted to the northern region of western North America (Alberta, Montana and Alaska). Exceptions consist of single taxa from Utah (Diabloceratops) and China (Sinoceratops), plus otherwise fragmentary remains from the southern Western Interior of North America. Here, we describe a remarkable new taxon, Nasutoceratops titusi n. gen. et sp., from the late Campanian Kaiparowits Formation of Utah, represented by multiple specimens, including a nearly complete skull and partial postcranial skeleton. Autapomorphies include an enlarged narial region, pneumatic nasal ornamentation, abbreviated snout and elongate, rostrolaterally directed supraorbital horncores. The subrectangular parietosquamosal frill is relatively unadorned and broadest in the mid-region. A phylogenetic analysis indicates that Nasutoceratops is the sister taxon to Avaceratops, and that a previously unknown subclade of centrosaurines branched off early in the group’s history and persisted for several million years during the late Campanian. As the first well-represented southern centrosaurine comparable in age to the bulk of northern forms, Nasutoceratops provides strong support for the provincialism hypothesis, which posits that Laramidia—the western landmass formed by inundation of the central region of North America by the Western Interior Seaway—hosted at least two coeval dinosaur communities for over a million years of late Campanian time.
Philippe J. R. Kok, Monique Hölting, Raffael Ernst
A third microendemic to the Iwokrama Mountains of central Guyana: a new “cryptic” species of Allobates Zimmerman and Zimmerman, 1988 (Anura: Aromobatidae)
Organisms Diversity & Evolution July 2013
The aromobatid frog Allobates amissibilis sp. nov. is described from a very limited area in the Iwokrama Mountains at elevations between 160 and 950 m, in central Guyana, South America. The new taxon is diagnosed from other Allobates species by morphology, bioacoustics, and genetics, and can be distinguished readily from known congeners by cryptic colouration, small size (16.3–17.8 mm snout-vent length), absence of distinct dorsal pattern in living adult individuals, presence of a distinctly enlarged tubercle on each eyelid, diffuse broad oblique lateral stripe extending from groin to about midbody length, sexually dimorphic throat colouration (pinkish grey, suffused with dark pigment in male, immaculate cream to yellow in female), belly cream to yellow in both sexes, and distinct vocalisation formed by calls of usually 9–12 notes emitted between silent intervals of usually ca. 2–6 s, with a dominant frequency ranging from 5,064 to 5,845 Hz. The new species is the third microendemic reported from the Iwokrama Mountains together with the caecilian Caecilita iwokramae and the lizard Gonatodes timidus. We recommend considering the conservation status of the new species as Data Deficient, and highlight that environmental impact assessments are needed to refine its IUCN threat status.
Zootaxa 3691 (1): 153–164 (18 Jul. 2013)
Description of Notoglanidium pembetadi new species (Siluriformes: Claroteidae) from the Kouilou-Niari River, Republic of the Congo
EMMANUEL VREVEN, ARMEL IBALA ZAMBA, VICTOR MAMONEKENE & TOM GEERINCKX
A new claroteid catfish, Notoglanidium pembetadi, is described from the Kouilou-Niari River basin (Republic of the Congo). This species can be distinguished from all other currently known Notoglanidium species as well as from the very similar Anaspidoglanis boutchangai, to which two specimens have erroneously been attributed in the past, by the following combination of characters: II, 10–13 dorsal-fin rays; long dorsal-fin base (21.1–24.4% SL); short predorsal distance (30.1–33.5% SL); and short prepelvic distance (40.1–45.4% SL).
Zootaxa 3691 (1): 165–191 (18 Jul. 2013)
Revision of Notoglanidium and related genera (Siluriformes: Claroteidae) based on morphology and osteology
TOM GEERINCKX, EMMANUEL VREVEN, MANUEL DIERICK, LUC VAN HOOREBEKE & DOMINIQUE ADRIAENS
Apart from the well-demarcated genera Auchenoglanis and Parauchenoglanis, Auchenoglanidinae, one of the two subfamilies of the African catfish family Claroteidae, suffers from poor resolution at the generic level. For the remaining genera, Notoglanidium, Liauchenoglanis, Platyglanis and Anaspidoglanis, generic discriminations are rudimentary. In addition, several included species are poorly defined and barely represented in scientific collections. Until now, no study has included morphological data for all currently known species, and for many species osteological data were non-existent. Molecular data for most species are lacking as well. Here, a comprehensive account of the morphology and osteology is given of all species included in these four genera. Using computed tomography (CT scanning) as well as clearing and staining, osteological characters were combined with biometric, meristic and other morphological data to revise the status of these genera and included species. Morphological and osteological data, submitted to a phylogenetic analysis, agree with metric and meristic data that all Liauchenoglanis, Platyglanis and Anaspidoglanis cannot be discerned from Notoglanidium; their genus and type species descriptions fail to be distinguished from Notoglanidium. Here their synonymy is proposed, resulting in a single valid genus, including nine species of which the validity is confirmed. A key to the genus and included species, as well as a diagnosis and description for each of them, are provided.
Zootaxa 3691 (1): 192–198 (18 Jul. 2013)
A new distinctively banded species of Panaqolus (Siluriformes: Loricariidae) from the western Amazon Basin in Peru
NATHAN K. LUJAN, SARAH STEELE & MIQUEL VELASQUEZ
Panaqolus albivermis is described as a new species based on four specimens from the San Alejandro River, a tributary of the upper Ucayali River in central Peru. Panaqolus albivermis is diagnosed from all other Panaqolus except P. maccus by having head, body, and fins with widely separated small white to yellow spots, vermiculations, and/or thin oblique bands on a black base (vs. exclusively small white to yellow spots on a black base in P. albomaculatus, generally broad oblique bands of alternating light to dark brown in P. changae, P. gnomus, P. purusiensis, and a uniformly dark gray to black body color in P. dentex, P. koko, and P. nocturnus); P. albivermis can be diagnosed from P. maccus by having a black base color (vs. brown), by having parallel dentary tooth cups (vs. acute intermandibular tooth cup angle), and by having a larger known adult body size (95.8 mm SL vs. 84.8).
N. Pelegrin, J.M. Chani, A.L. Echevarria, E.H. Bucher, Habitat degradation may affect niche segregation patterns in lizards, Acta Oecologica, Volume 51, August 2013, Pages 82-87, ISSN 1146-609X, http://dx.doi.org/10.1016/j.actao.2013.06.006.
Lizards partition resources in three main niche dimensions: time, space and food. Activity time and microhabitat use are strongly influenced by thermal environment, and may differ between species according to thermal requirements and tolerance. As thermal characteristics are influenced by habitat structure, microhabitat use and activity of lizards can change in disturbed habitats. We compared activity and microhabitat use of two abundant lizard species of the Semi-arid Chaco of Argentina between a restored and a highly degraded Chaco forest, to determine how habitat degradation affects lizard segregation in time and space, hypothesizing that as activity and microhabitat use of lizards are related to habitat structure, activity and microhabitat use of individual species can be altered in degraded habitats, thus changing segregation patterns between them. Activity changed from an overlapped pattern in a restored forest to a segregated pattern in a degraded forest. A similar trend was observed for microhabitat use, although to a less extent. No correlation was found between air temperature and lizard activity, but lizard activity varied along the day and among sites. Contrary to what was believed, activity patterns of neotropical diurnal lizards are not fixed, but affected by multiple factors related to habitat structure and possibly to interspecific interactions. Changes in activity patterns and microhabitat use in degraded forests may have important implications when analyzing the effects of climate change on lizard species, due to synergistic effects.
The effect of premedication with ketamine, alone or with diazepam, on anaesthesia with sevoflurane in parrots (Amazona aestiva)
de Paula VV, Otsuki DA, Auler JO, Nunes TL, Ambrósio AM, Fantoni DT
BMC Veterinary Research 2013, 9:142 (17 July 2013)
Premedication is rarely used in avian species. The aim of this study was to evaluate the effect of premedication on the quality of sevoflurane induction and anaesthesia in parrots. We hypothesised that premedication would facilitate handling and decrease the minimum anaesthetic dose (MAD). Thirty-six adult parrots were randomly distributed in three groups: group S (n = 12) was premedicated with NaCl 0.9%; group KS (n = 12) was premedicated with 10 mg.kg-1 ketamine; and group KDS (n = 12) was premedicated with 10 mg.kg-1 ketamine and 0.5 mg.kg-1 diazepam, delivered intramuscularly. After induction using 4.5% sevoflurane introduced through a facemask, the MAD was determined for each animal. The heart rate (HR), respiratory rate (RR), systolic arterial blood pressure (SAP), and cloacal temperature (CT) were recorded before premedication (T0), 15 minutes after premedication (T1), and after MAD determination (T2). Arterial blood gas analyses were performed at T0 and T2. The quality of anaesthesia was evaluated using subjective scales based on animal behaviour and handling during induction, maintenance, and recovery. Statistical analyses were performed using analysis of variance or Kruskal-Wallis tests followed by Tukey’s or Dunn’s tests.
The minimal anaesthetic doses obtained were 2.4 +/- 0.37%, 1.7 +/- 0.39%, and 1.3 +/- 0.32% for groups S, KS, and KDS, respectively. There were no differences in HR, RR, or CT among groups, but SAP was significantly lower in group S. Sedation was observed in both the premedicated S-KS and S-KDS groups. There were no differences in the quality of intubation and recovery from anaesthesia among the three groups, although the induction time was significantly shorter in the pre-medicated groups, and the KS group showed less muscle relaxation.
Ketamine alone or the ketamine/diazepam combination decreased the MAD of sevoflurane in parrots (Amazona aestiva). Ketamine alone or in combination with diazepam promoted a good quality of sedation, which improved handling and reduced the stress of the birds. All protocols provided safe anaesthesia in this avian species.
Physical Sciences – Earth, Atmospheric, and Planetary Sciences – Biological Sciences – Evolution:
Robert A. DePalma II, David A. Burnham, Larry D. Martin, Bruce M. Rothschild, and Peter L. Larson
Physical evidence of predatory behavior in Tyrannosaurus rex
PNAS 2013 ; published ahead of print July 15, 2013, doi:10.1073/pnas.1216534110
Feeding strategies of the large theropod, Tyrannosaurus rex, either as a predator or a scavenger, have been a topic of debate previously compromised by lack of definitive physical evidence. Tooth drag and bone puncture marks have been documented on suggested prey items, but are often difficult to attribute to a specific theropod. Further, postmortem damage cannot be distinguished from intravital occurrences, unless evidence of healing is present. Here we report definitive evidence of predation by T. rex: a tooth crown embedded in a hadrosaurid caudal centrum, surrounded by healed bone growth. This indicates that the prey escaped and lived for some time after the injury, providing direct evidence of predatory behavior by T. rex. The two traumatically fused hadrosaur vertebrae partially enclosing a T. rex tooth were discovered in the Hell Creek Formation of South Dakota.
John F. Benson, Brent R. Patterson
Inter-specific territoriality in a Canis hybrid zone: spatial segregation between wolves, coyotes, and hybrids
Oecologia July 2013
Gray wolves (Canis lupus) and coyotes (Canis latrans) generally exhibit intraspecific territoriality manifesting in spatial segregation between adjacent packs. However, previous studies have found a high degree of interspecific spatial overlap between sympatric wolves and coyotes. Eastern wolves (Canis lycaon) are the most common wolf in and around Algonquin Provincial Park (APP), Ontario, Canada and hybridize with sympatric gray wolves and coyotes. We hypothesized that all Canis types (wolves, coyotes, and hybrids) exhibit a high degree of spatial segregation due to greater genetic, morphologic, and ecological similarities between wolves and coyotes in this hybrid system compared with western North American ecosystems. We used global positioning system telemetry and probabilistic measures of spatial overlap to investigate spatial segregation between adjacent Canis packs. Our hypothesis was supported as: (1) the probability of locating wolves, coyotes, and hybrids within home ranges or core areas of adjacent packs was low; and the amount of shared space use was negligible. Spatial segregation did not vary substantially in relation to genotypes of adjacent packs or local environmental conditions (i.e., harvest regulations or road densities). We provide the first telemetry-based demonstration of spatial segregation between wolves and coyotes, highlighting the novel relationships between Canis types in the Ontario hybrid zone relative to areas where wolves and coyotes are reproductively isolated. Territoriality among Canis may increase the likelihood of eastern wolves joining coyote and hybrid packs, facilitate hybridization, and could play a role in limiting expansion of the genetically distinct APP eastern wolf population.
D’Emic MD, Whitlock JA, Smith KM, Fisher DC, Wilson JA (2013) Evolution of High Tooth Replacement Rates in Sauropod Dinosaurs. PLoS ONE 8(7): e69235. doi:10.1371/journal.pone.0069235
Tooth replacement rate can be calculated in extinct animals by counting incremental lines of deposition in tooth dentin. Calculating this rate in several taxa allows for the study of the evolution of tooth replacement rate. Sauropod dinosaurs, the largest terrestrial animals that ever evolved, exhibited a diversity of tooth sizes and shapes, but little is known about their tooth replacement rates.
We present tooth replacement rate, formation time, crown volume, total dentition volume, and enamel thickness for two coexisting but distantly related and morphologically disparate sauropod dinosaurs Camarasaurus and Diplodocus. Individual tooth formation time was determined by counting daily incremental lines in dentin. Tooth replacement rate is calculated as the difference between the number of days recorded in successive replacement teeth. Each tooth family in Camarasaurus has a maximum of three replacement teeth, whereas each Diplodocus tooth family has up to five. Tooth formation times are about 1.7 times longer in Camarasaurus than in Diplodocus (315 vs. 185 days). Average tooth replacement rate in Camarasaurus is about one tooth every 62 days versus about one tooth every 35 days in Diplodocus. Despite slower tooth replacement rates in Camarasaurus, the volumetric rate of Camarasaurus tooth replacement is 10 times faster than in Diplodocus because of its substantially greater tooth volumes. A novel method to estimate replacement rate was developed and applied to several other sauropodomorphs that we were not able to thin section.
Differences in tooth replacement rate among sauropodomorphs likely reflect disparate feeding strategies and/or food choices, which would have facilitated the coexistence of these gigantic herbivores in one ecosystem. Early neosauropods are characterized by high tooth replacement rates (despite their large tooth size), and derived titanosaurs and diplodocoids independently evolved the highest known tooth replacement rates among archosaurs.
Gema Martin-Ordas, Dorthe Berntsen, Josep Call, Memory for Distant Past Events in Chimpanzees and Orangutans, Current Biology, Available online 18 July 2013, ISSN 0960-9822, http://dx.doi.org/10.1016/j.cub.2013.06.017.Determining the memory systems that support nonhuman animals’ capacity to remember distant past events is currently the focus an intense research effort and a lively debate [1–3]. Comparative psychology has largely adopted Tulving’s framework by focusing on whether animals remember what-where-when something happened (i.e., episodic-like memory) [4–6]. However, apes have also been reported to recall other episodic components  after single-trial exposures [8, 9]. Using a new experimental paradigm we show that chimpanzees and orangutans recalled a tool-finding event that happened four times 3 years earlier (experiment 1) and a tool-finding unique event that happened once 2 weeks earlier (experiment 2). Subjects were able to distinguish these events from other tool-finding events, which indicates binding of relevant temporal-spatial components. Like in human involuntary autobiographical memory, a cued, associative retrieval process triggered apes’ memories: when presented with a particular setup, subjects instantaneously remembered not only where to search for the tools (experiment 1), but also the location of the tool seen only once (experiment 2). The complex nature of the events retrieved, the unexpected and fast retrieval, the long retention intervals involved, and the detection of binding strongly suggest that chimpanzees and orangutans’ memories for past events mirror some of the features of human autobiographical memory.
Ueno, A. and Suzuki, K. (2013), Comparison of learning ability and memory retention in altricial (Bengalese finch, Lonchura striata var. domestica) and precocial (blue-breasted quail, Coturnix chinensis) birds using a color discrimination task. Animal Science Journal. doi: 10.1111/asj.12092
The present study sought to assess the potential application of avian models with different developmental modes to studies on cognition and neuroscience. Six altricial Bengalese finches (Lonchura striata var. domestica), and eight precocial blue-breasted quails (Coturnix chinensis) were presented with color discrimination tasks to compare their respective faculties for learning and memory retention within the context of the two developmental modes. Tasks consisted of presenting birds with discriminative cues in the form of colored feeder lids, and birds were considered to have learned a task when 80% of their attempts at selecting the correctly colored lid in two consecutive blocks of 10 trials were successful. All of the finches successfully performed the required experimental tasks, whereas only half of the quails were able to execute the same tasks. In the learning test, finches required significantly fewer trials than quails to learn the task (finches: 13.5 ± 9.14 trials, quails: 45.8 ± 4.35 trials, P < 0.05), with finches scoring significantly more correct responses than quails (finches: 98.3 ± 4.08%, quails: 85.0 ± 5.77% at the peak of the learning curve). In the memory retention tests, which were conducted 45 days after the learning test, finches retained the ability to discriminate between colors correctly (95.0 ± 4.47%), whereas quails did not retain any memory of the experimental procedure and so could not be tested. These results suggested that altricial and precocial birds both possess the faculty for learning and retaining discrimination-type tasks, but that altricial birds perform better than precocial birds in both faculties. The present findings imply that developmental mode is an important consideration for assessing the suitability of bird species for particular experiments.
Khannoon E.R., Evans S.E.. 2013. The embryonic development of the Egyptian cobra Naja h. haje (Squamata: Serpentes: Elapidae). – Acta Zoologica (Stockholm) 00: 000–000
The Egyptian cobra, Naja h. haje, is the largest of the African cobras and is a member of a successful and medically important species complex found throughout Africa, north and south of the Sahara, as well as across the Arabian Peninsula to Oman. Although its phylogenetic position and venom characteristics have been well studied, its development has not. Here, we present a normal staging table for N. h. haje, based on external features. Comparison with firstly the Asian monocled cobra, Naja kaouthia, and then with the small number of other oviparous snake species, allowed us to examine whether differences between two species in the same genus were of the same type and magnitude as those between unrelated genera. In fact, at least with respect to external features, we found a similar level of disparity. N. h. haje embryos lagged behind those of N. kaouthia in body and head scale development, size in ovo and hatchling length, despite having a slightly shorter incubation period and a somewhat larger adult size. Some of these differences may have been the result of differing incubation temperatures. Nonetheless, there does appear to be a broadly conserved pattern of in ovo development in at least macrostomatan snakes.
Bolt, L. M. (2013), Squealing rate indicates dominance rank in the male ring-tailed lemur (Lemur catta). Am. J. Primatol.. doi: 10.1002/ajp.22179
Squeals are sharp and forceful short-range vocalizations used as aggressive and submissive agonistic signals by many mammalian species. The ring-tailed lemur (Lemur catta), a female-dominant strepsirhine primate, has a male-specific squeal call with proposed male–male agonistic functions and male–female courtship functions that have never been empirically tested. The goal of my study is to clarify why ring-tailed lemur males squeal at other males and females by applying the handicap hypothesis to this male-specific vocalization. This hypothesis has rarely been tested in primates, and this study elucidates how the rate of a male-specific call relates to male–male and male–female behavior in a Malagasy strepsirhine. To test whether males squeal towards other males to assert dominance, I predict that male squealing rate is positively correlated with dominance rank. I further predict that male ring-tailed lemurs squeal at other males while engaged in agonistic interactions, and that squealing during an interaction is positively correlated with winning that encounter. To test whether males squeal towards females as a mate attraction signal, I predict that male squealing rate is higher on estrus days, and that estrous females indicate attraction by approaching squealing males. From March to July 2010, 480 hr of focal data were collected on 25 males aged three and older at Beza Mahafaly Special Reserve, Madagascar. I continuously observed each male for 30 min at a time and recorded all agonistic interactions and squeal vocalizations using 1–0 sampling at 2.5-min intervals. Squealing rate was higher during times of male–male agonism when compared to times without male–male agonism, and males with higher dominance ranks had higher squealing rates. In contrast, the mate attraction hypothesis was not supported. My results suggest that the male squeal is an agonistic signal when used in male–male interaction in ring-tailed lemurs, but does not specifically indicate aggression or submission.
Janiszewski, T., Minias, P. and Wojciechowski, Z. (2013), Occupancy reliably reflects territory quality in a long-lived migratory bird, the white stork. Journal of Zoology. doi: 10.1111/jzo.12059
Patterns of territory occupancy were studied in the population of ca. 200 pairs of white stork Ciconia ciconia breeding in central Poland from 1994 to 2011. We tested whether occupation rate in this species correlated with different indices of territory quality and reproductive performance of nesting birds. Territory occupancy deviated significantly from random pattern, as nearly half of the territories were occupied for over 75% of all breeding seasons. It was found that white storks returning to breeding grounds in spring settled earlier in the territories of higher occupancy. There was a positive association between territory occupancy and productivity of storks, which could be explained by the lower prevalence of brood reduction in the longer occupied territories. Finally, we demonstrated that occupancy positively correlated with the share of high-quality habitats (wetlands) in the foraging territories of storks. All these relationships indicate that territory occupancy may be used to reliably assess attractiveness of particular nesting territories and to identify key areas for white storks. We also suggest that the application of this simple measure of territory quality could well enhance conservation efforts directed at long-lived migratory birds.
Fernholm, B., Norén, M., Kullander, S. O., Quattrini, A. M., Zintzen, V., Roberts, C. D., Mok, H.-K. and Kuo, C.-H. (2013), Hagfish phylogeny and taxonomy, with description of the new genus Rubicundus (Craniata, Myxinidae). Journal of Zoological Systematics and Evolutionary Research. doi: 10.1111/jzs.12035
A recent phylogenetic analysis of the Myxinidae based on the 16S rRNA gene resulted in synonymization of Paramyxine with Eptatretus. This created homonymy of Paramyxine fernholmi with Eptatretus fernholmi and Paramyxine wisneri with Eptatretus wisneri. In order to resolve this nomenclatural dilemma, we made a more extensive phylogenetic assessment of the Myxinidae and examined the nomenclature of the family. We used 75 sequences (37 of which new for this study) of a 561 bp fragment of the 16S rRNA gene, representing 33 species, and 72 sequences (37 of which new for this study) of a 687 bp fragment of the cytochrome c oxidase subunit I (COI) gene, representing 23 species, to reconstruct the phylogeny of Myxinidae. The monophyly of the subfamily Myxininae, traditionally characterized by having a single pair of external gill openings, was rejected (0.50 Bayesian posterior probability) by the 16S analysis, but supported by the COI and combined COI+16S analyses (0.99 and 0.81 Bpp, respectively). The monophyly of the subfamily Eptatretinae, characterized by having several pairs of external gill openings, was not supported by the 16S analysis and rejected by the COI and combined COI+16S analysis due to the placement of Eptatretus lopheliae as the earliest branch of Myxinidae (0.71 and 0.57 Bpp, respectively). Eptatretus lopheliae and Eptatretus rubicundus formed a monophyletic group and were allocated to a new genus, Rubicundus, characterized by the presence of an elongated tubular nostril and reddish coloration. A new monotypic subfamily, Rubicundinae, was proposed for Rubicundus. The synonymy of the genera Paramyxine and Quadratus with Eptatretus was confirmed. E. fernholmi is renamed Eptatretus luzonicus. Eptatretus wisneri was renamed Eptatretus bobwisneri. Petromyzon cirrhatus Forster, 1801, Homea banksii Fleming, 1822, and Bdellostoma forsteri Müller, 1836 are synonyms, but no type specimens are known to exist. Petromyzon cirrhatus was designated as type species of Eptatretus, conserving present usage. Gastrobranchus dombeyi Shaw, 1804 has priority over other names for Chilean myxinids. Bdellostoma stoutii was designated as type species of Polistotrema Gill. The validity of the Western Atlantic Myxine limosa as distinct from the Eastern Atlantic Myxine glutinosa was confirmed.