[Paleontology • 2019] Convolosaurus marri • A New Basal Ornithopod (Dinosauria: Ornithischia) from the Early Cretaceous of Texas, USA

Convolosaurus marri

Andrzejewski, Winkler & Jacobs, 2019

 DOI: 10.1371/journal.pone.0207935

Abstract

Material from a minimum of twenty-nine individuals of a new ornithopod, represented by nearly every skeletal element, was recovered from the Proctor Lake locality in the Twin Mountains Formation (Aptian) of north-central Texas. This material includes various ontogenetic stages, providing insight into the growth patterns of this species. The new ornithopod, Convolosaurus marri gen. et sp. nov., is recovered outside of Iguanodontia, but forms a clade with Iguanodontia exclusive of Hypsilophodon foxii. The presence and morphology of four premaxillary teeth along with a combination of both basal and derived characters distinguish this taxon from all other ornithopods. Basal characters present in C. marri including the presence of premaxillary teeth, the shape of the dentary teeth, and position of the pterygoid wing on the quadrate, whereas the presence of opisthocoelous cervical vertebrae, large proximal caudal neural spines, and curved maxillary tooth roots suggest C. marri is more derived than 80% of the basal neornithischians included in this analysis.

Fig 2. Convolosaurus marri, articulated specimens.
 (A) SMU 70456, articulated subadult individual on display at the Proctor Lake Corps of Engineers Office. Scale arrow equals 10 cm. (B) Composite skeleton on display at the Perot Museum of Nature and Science. Scale bar equals 10 cm. (C) SMU 75379 and SMU 75380, partial articulated skeletons found stacked on one another. Scale bar equals 5 cm.

Fig 4. Skull reconstruction. Skull reconstruction of Convolosaurus marri based on available specimens.

Abbreviations: A-articular, BO-basioccipital, D-dentary, F-frontal, J-jugal, L-lacrimal, MX-maxilla, N-nasal, OP-opisthotic, P-parietal, PD-predentary, PF-prefrontal, PMX-premaxilla, PO-postorbital, Q-quadrate, QJ-quadratojugal, SA-surangular, SOB-supraorbital, SQ-squamosal.

Fig 6. SMU 72834 anterior skull. (A) SMU 72834, anterior skull in right lateral view. (B) Illustration of SMU 72834, in right lateral view (David Baker).

Abbreviations: D-dentary, L-lacrimal, MX-maxilla, PMX-premaxilla, PD-predentary, QJ-quadratojugal. Scale bar equals 5 cm.

Systematic Paleontology

DINOSAURIA Owen, 1842

ORNITHISCHIA Seeley, 1887

NEORNITHISCHIA Cooper, 1985

CERAPODA Sereno, 1986

ORNITHOPODA Marsh, 1881

Convolosaurus marri gen. et sp. nov. 

Holotype: SMU 72834, a skull and partial articulated skeleton with 9 cervical vertebrae; 15 dorsal vertebrae; 6 sacral vertebrae; 23 caudal vertebrae; right and partial left scapula; right and partial left coracoids; left and partial right humeri; left ulna; left radius; partial left manus; articulated pelvis including the left and right ilia, proximal left and right ischia, partial prepubic rods; proximal and distal ends of the left and right femora and the mid-part of the left shaft; proximal left and right tibiae; and proximal left fibula. The type specimen, SMU 72834, is the largest individual in the sample measuring approximately 2.5–3 m in length; however, this skeleton does not represent a full grown adult, thus the adult size of this species in unknown.

Diagnosis: The presence of four premaxillary teeth with proximodistally oriented sulcus on the buccal surface distinguishes Convolosaurus marri gen. et sp. nov. from all other ornithopods. Further, it can be distinguished from other basal ornithopods by a unique combination of primitive and derived character states. Primitive character states include the presence of premaxillary teeth and two supraorbitals that extend across the entire orbit. Derived character states include: curved maxillary tooth roots; opisthocoelous cervical vertebrae; sacral neural spines twice the height of the sacral centra; proximal caudal neural spines 1.5 times the height of the centrum; expanded ischial ‘foot’; shallow intercondylar groove on the anterior surface of the femur; and a laterally compressed prepubic process.

Etymology: The generic name Convolosaurus translates from Latin meaning “flocking lizard” referring to clusters of juvenile specimens. The species name marri is in honor of Dr. Ray H. Marr who produced the Society of Vertebrate Paleontology videos “We are SVP” and “About the SVP Logo” posted on the SVP website (vertpaleo.org), and who is a strong proponent of students at Southern Methodist University (SMU).

Fig 30. Strict consensus tree produced from phylogenetic analysis. Strict consensus tree of 96 most parsimonious trees recovered from phylogenetic analysis. Bootstrap support values >50% listed beneath nodes.

   

Conclusions: 

The Proctor Lake fossil locality contains a wealth of specimens providing not only nearly complete individual skeletons, but also insight into ontogeny and population structure. The femoral length distribution of 29 individuals from the Proctor Lake locality indicates a high mortality rate among the smallest and presumably youngest individuals. Clusters of individuals of varying sizes suggest individuals flocked together long after hatching perhaps for protection against predators. The specimens recovered from Proctor Lake reveal a new species of basal ornithopod with a unique set of both basal and derived characters. Characters including an expanded ischial foot, curved maxillary tooth roots, and opisthocoelus cervical vertebrae position Convolosaurus marri in a clade exclusive of most basal ornithischians including Hypsilophodon foxii [Galton, 1974], but characters such as the presence of premaxillary teeth, shape of the frontals, and the position of the pterygoid wing on the quadrate position C. marri outside of Iguanodontia. Thus, this new species provides crucial information on the evolution of basal neornithischians.

 Kate A. Andrzejewski, Dale A. Winkler and Louis L. Jacobs. 2019. A New Basal Ornithopod (Dinosauria: Ornithischia) from the Early Cretaceous of Texas.  PLoS ONE 14(3): e0207935. DOI: 10.1371/journal.pone.0207935

[Invertebrate • 2019] Revision of Condyloderes (Kinorhyncha, Cyclorhagida) Including Description of Condyloderes shirleyi sp. nov.

Condyloderes paradoxus Higgins, 1969

in Neuhaus, Zotto, Yamasaki & Higgins, 2019.

DOI: 10.11646/zootaxa.4561.1.1 

Abstract

The description of a new representative of the species-poor genus Condyloderes Higgins, 1969 from the Northeast Pacific (Alaska) is reported. The analyzed specimens of Condyloderes shirleyi sp. nov. showed a significant variation of numerous morphological characters, along with female-specific traits known also from other congeneric species. These findings stimulated the re-investigation of the type material of the six species of Condyloderes described so far, i.e., C. kurilensis Adrianov & Maiorova, 2016, C. megastigma Sørensen, Rho & Kim, 2010b, C. multispinosus (McIntyre, 1962) Higgins, 1969, C. paradoxus Higgins, 1969, C. setoensis Adrianov, Murakami & Shirayama, 2002, and C. storchi Higgins, 2004 in Martorelli & Higgins, 2004. Our study allowed to reveal various morphological novelties and to emend the diagnosis of these species and of the genus Condyloderes. Furthermore, our analysis led to synonymize C. megastigma with C. setoensis. The results of our investigation about the significant variation in C. shirleyi sp. nov. raise a wider question on species identity within Kinorhyncha, underscoring the necessity, if possible, to describe new species from a higher number of specimens and to concentrate on the morphological variation of the going-to-be-described species.

Keywords: Centroderidae, intraspecific variation, meiofauna, new species, taxonomy

Holotype males of Condyloderes paradoxus (USNM W37460). 

 Birger Neuhaus, Matteo Dal Zotto, Hiroshi Yamasaki and Robert P. Higgins. 2019. Revision of Condyloderes (Kinorhyncha, Cyclorhagida) Including Description of Condyloderes shirleyi sp. nov. Zootaxa. 4561(1); 1-91. DOI: 10.11646/zootaxa.4561.1.1

[Crustacea • 2018] Cambarus loughmani • A New Species of Crayfish (Decapoda: Cambaridae) endemic to the Pre-glacial Teays River Valley in West Virginia, USA

Cambarus loughmani

Foltz, Sadecky, Fetzner & Thoma

in Foltz, Sadecky, Myers, Fetzner, Welsh, Stocker, Glon & Thoma, 2018. 

 DOI: 10.1080/00222933.2018.1557271

Blue Teays Mudbug  ||    facebook.com/WLUCrayfish

ABSTRACT

A new species of crayfish, Cambarus loughmani sp. nov., is described from the preglacial Teays River Valley of Cabell, Kanawha, Lincoln, Mason, and Putnam counties, West Virginia. The species was previously considered to be part of the Cambarus dubius complex. Loughman et al. restricted C. dubius to an orange colour morph found in central and northern portions of the Allegheny Mountains and Appalachian Plateau in central West Virginia, western Maryland, and south-central Pennsylvania. The new species described herein can be distinguished from all other members of Cambarus Erichson, 1846 by a double row of cristiform tubercles on the palm, an open areola with two rows of punctations, and a consistent blue colouration.

KEYWORDS: Appalachian Plateau, Cambarus, crayfish, new species, West Virginia

Figure 3. Dorsal view of a female specimen of Cambarus loughmani collected from the type locality, burrows adjacent to Little Island Creek, Lincoln County, West Virginia, displaying typical life colours for the species.

Photo by Guenter Schuster.

  facebook.com/WLUCrayfish

Cambarus loughmani Foltz, Sadecky, Fetzner and Thoma sp. nov.

 Cambarus dubius Faxon 1884: 114 [in part]. Faxon 1885: 70, pl. 4: fig. 3; pl. 8: figs 7, 7ʹ [in part]; Dewees 1972: 1, figs 1b–l, 2c–h, 3, 4, 5b–h, 6–16 [in part]. 

Cambarus carolinus dubius.–Faxon 1914: 396, 425 [in part]. 

Cambarus (Jugicambarus) dubius.–Hobbs and Bouchard 1973: 62 [in part]; Hobbs 1974: 18, fig. 60 [in part]; Hobbs 1989: 22, fig. 78 [in part]; Jezerinac et al. 1995: 121, fig. 61 [in part]. 

Cambarus aff. dubius. – Loughman et al. 2015: 534 [in part].

Etymology: The authors of this paper name this crayfish in honour of Dr Zachary J. Loughman, assistant professor of biology, West Liberty University. In recent years, prior to the naming of this species, Dr Loughman has served as one of the primary astacological researchers, contributing greatly to our understanding of ecology, taxonomy, conservation and distribution of Appalachian crayfish species. It is fitting that this crayfish be named in his honour, as both he and this crayfish are reclusive, hard to track down, and when faced with adversity never back down and often advance with arms flailing. The authors of this paper are composed of a mix of age classes. For the younger authors, Dr Loughman has served as a teacher, advisor and mentor. For the older authors he has served as a colleague, collaborator and student. For all of us, he has been a friend and an inspiration. Common name: The suggested common name for this species is Blue Teays Mudbug as it inhabits the Teays River Valley.

David A. Foltz II, Nicole M. Sadecky, Greg A. Myers, James W. Fetzner Jr., Stuart A. Welsh, G. Whitney Stocker, Mael G. Glon and Roger F. Thoma. 2018. 

Cambarus loughmani, A New Species of Crayfish (Decapoda: Cambaridae) endemic to the Pre-glacial Teays River Valley in West Virginia, USA. Journal of Natural History.  52(45-46);  DOI: 10.1080/00222933.2018.1557271 

   facebook.com/WLUCrayfish/posts/1332349053573749

[Crustacea • 2019] Lacunicambarus chimera • A New Species of Burrowing Crayfish (Decapoda: Cambaridae) from Illinois, Indiana, Kentucky, and Tennessee

Lacunicambarus chimera Glon & Thoma,

in Glon, Thoma, Daly & Freudenstein, 2019. 

Crawzilla Crawdad  ||  DOI:  10.11646/zootaxa.4544.4.1

Photo by Guenter Schuster.

Abstract

Lacunicambarus diogenes (Girard 1852) was, until recently, considered to be one of the most widely distributed North American crayfish species, occurring in 31 U.S. States and one Canadian province east of the North American Rocky Mountains. Glon et al. (2018) investigated this claim and found that L. diogenes sensu lato was actually a species complex. The authors redescribed L. diogenes and restricted its range to the Atlantic Coastal Plain and Piedmont ecoregions of eastern North America. In doing so, they also revealed the existence of several probable undescribed species of Lacunicambarus that were previously considered to be L. diogenes. Here, we use morphological and molecular techniques to distinguish and describe one of these species: Lacunicambarus chimera sp. nov., a large primary burrowing crayfish found in parts of the Lower Mississippi, Ohio, Tennessee and Upper Mississippi River Basins. Lacunicambarus chimera is morphologically similar to L. diogenes, from which it can be distinguished by the greater number of spines on the ventrolateral margin of its merus, its wider antennal scale terminating in a short spine, and the presence of a single longitudinal stripe on the dorsal side of its abdomen. We also provide an updated key to Lacunicambarus.

Keywords: Crustacea, burrowing crayfish, systematics, taxonomy, revision, North America, freshwater, Old Ohio River

FIGURE 6. Dorsal view of Form I holotypic male of Lacunicambarus chimera (OSUMC 10650).

Photo by Guenter Schuster.

Taxonomy 

Family Cambaridae Hobbs 1942 

Genus Lacunicambarus (Hobbs 1969) 

Lacunicambarus chimera Glon & Thoma sp. nov.

Cambarus obesus Forbes 1876:6 [in part]. 

Cambarus diogenes Hay 1895:478 [in part]. Ortmann 1905:123 [in part]. Rhoades 1944:111 [in part]. Eberly 1954:283 [in part]. Brown 1955:62 [in part]. Marlow 1960:229 [in part]. Page 1985:433 [in part]. Page & Mottesi 1995:23 [in part]. Taylor et al. 1996:29 [in part]. Simon 2001:104 [in part]. Taylor et al. 2007:382 [in part]. Taylor & Schuster 2004:80 [in part]. Taylor Schuster & Wylie 2015:66 [in part]. 

Cambarus diogenes diogenes Marlow 1960:233 [in part]. 

Cambarus (Lacunicambarus) diogenes diogenes Hobbs 1969:110 [in part]; 1974:20 [in part]. Bouchard 1972:56 [in part]; 1974:595 [in part]. 

Cambarus (Lacunicambarus) diogenes Hobbs 1989: 24 [in part]. Thoma et al. 2005:334 [in part]. Thoma & Armitage 2008:iii [in part]. 

Cambarus cf. diogenes Glon 2017:55.

 Lacunicambarus aff. diogenes Glon et al. 2018:604 [in part].

Diagnosis. Eyes pigmented, not reduced. Rostrum curved downwards in lateral view, margins converging, slightly thickened, without marginal spines or tubercles, lacking median carina, shallowly excavated. Acumen distinctly delimited basally by 45° angles. Cephalothorax cylindrical, with 3–10 (mean ± sd: 6 ± 1) small tubercles lining posterior margin of cervical groove. Anteroventral branchiostegal tubercles small, numbering 8–29 (mean ± sd: 18 ± 4). Suborbital angle acute. Postorbital ridges developed, lacking anterior spine or tubercle. Areola obliterated, constituting, in adults, 38–45% (mean ± sd: 42 ± 0 %) of entire length of cephalothorax. Antennal scale 2.41 to 3.35 (mean ± sd: 2.80 ± 0.18) times as long as wide, broadest distal to midlength, terminating in small spine, mesial margin forming straight edge. Dorsomesial margin of palm of chelae with 3 rows of tubercles, mesial-most row normally consisting of 6–10 (mean ± sd: 7 ± 1) probolos tubercles, running parallel to second row with 4–9 (mean ± sd: 6 ± 1) probolos tubercles, third row running diagonally from mesial base of palm to lateral dactyl articulation in the form of 5–8 (mean ± sd: 7 ± 1) subprobolos tubercles located in shallow dimples. No tufts of elongated setae at mesial base of fixed finger. Opposable margin of dactyl weakly concave at base. Ratio of dactyl length to palm length 1.78–2.49 (mean ± sd: 2.10 ± 0.16). Dorsomedian longitudinal ridges of dactyl and fixed finger of propodus weakly developed. Dorsolateral impression at base of propodus moderate. Ventral surface of chelae with 0–5 (mean ± sd: 2 ± 1) subpalmar tubercles. Mesial margin of dactyl with 12–33 (mean ± sd: 22 ± 4) prominent tubercles. Ventral surface of carpus with single spine on mesial articular rim, mesial margin with 4–10 (mean ± sd: 7 ± 1) spines of varying sizes. Merus spines numbering 2–9 (mean: 5 ± 2) on ventrolateral margin and 7–16 (mean ± sd: 11 ± 2) on ventromesial margin. Mesial ramus of uropod with distomedian spine not reaching caudal margin. Gonopods of Form I males contiguous at base, with moderately pronounced umbo near midlength of caudal surface; terminal elements consisting of 1) short, tapering, distally truncate central projection lacking subapical notch, shorter than mesial process, directed caudally at approximately 90°, reaching past margin of umbo, 2) mesial process with conical base tipped with protruding finger, directed caudally at approximately 90° and overreaching umbo by noticeable amount and 3) inconspicuous caudal knob sometimes present at caudolateral base of central projection. Hooks on ischium of third pereiopods only. Female with annulus ventralis subquadrangular or kiteshaped, approximately as long as wide, rather deeply embedded in sternum, flexible, with posterior half sclerotized and anterior half mildly pliable.

....

....

Ecological Notes. As mentioned above, Lacunicambarus chimera is a primary burrowing crayfish species. Like other Lacunicambarus species, L. chimera is commonly dug from burrows in fine-grained soils along the floodplains of streams and rivers and in roadside ditches. We have also collected this species in burrows on the banks of manmade ponds and in ditches that were lined with large stones. The chimneys at the mouths of L. chimera burrows are often large and conspicuous, attaining heights of 30 cm or more. These burrows, like those of other primary burrowing crayfishes, provide habitat for many other organisms (e.g., Creaser 1931; Pintor & Soluk 2006; Thoma & Armitage 2008). Glon & Thoma (2017) specifically documented the use of L. chimera burrows as brooding burrows by eastern cicada killer wasps in Pike County, Indiana. 

Little is known about the ecology of L. chimera in situ, but specimens which we have kept in laboratory aquariums have readily consumed a variety of aquarium fish foods, snails, earth worms, and leaf litter from streams, suggesting that this species is an opportunistic omnivore. These specimens were mostly active at night, when they foraged around their enclosures. During the day, they rested inside of artificial burrows made from PVC pipes, occasionally twitching their antennae in response to stimuli. They did not appear to be particularly aggressive, compared to other crayfish species.

Crayfish Associates. We collected the following primary and secondary-burrowing crayfishes from burrows at sites where we found Lacunicambarus chimera: Creaserinus fodiens (Cottle 1863), C. hortoni (Hobbs & Fitzpatrick 1970), Faxonius immunis (Hagen 1870), L. ludovicianus, L. polychromatus, L. aff. polychromatus, Procambarus acutus (Girard 1852), P. clarkii (Girard 1852), P. gracilis (Bundy in Forbes 1876) and P. viaeviridis (Faxon 1914). While sampling for L. chimera, we focused primarily on sampling for burrowing crayfishes and therefore do not have records of the tertiary-burrowing crayfishes that undoubtedly inhabit open water adjacent to L. chimera burrows. 

Etymology. Our choice of the species epithet “chimera” stems from our first encounter with this species. The first specimens that we caught were freshly molted young adults (approximately 30 mm CL). These specimens bore a bright longitudinal gladiate stripe reminiscent of the stripe in L. ludovicianus, L. miltus, and some populations of L. polychromatus. The bright colors on these specimens were similar to those found in L. polychromatus, and the general shape of these specimens was reminiscent of L. diogenes. These features made L. chimera appear to be a chimera of multiple Lacunicambarus species. To honor the nickname given to this species when it was first discovered by Ray Jezerinac and Whitney Stocker, and also as a reference to its impressive size, we suggest the common name “Crawzilla Crawdad.” 

Mael G. Glon, Roger F. Thoma, Marymegan Daly and John V. Freudenstein. 2019.  Lacunicambarus chimera: A New Species of Burrowing Crayfish (Decapoda: Cambaridae) from Illinois, Indiana, Kentucky, and Tennessee. Zootaxa. 4544(4); 451–478.  DOI:  10.11646/zootaxa.4544.4.1

[Herpetology • 2018] Siren reticulata • Description of An Extant Salamander (Caudata: Sirenidae) from the Gulf Coastal Plain of North America: The Reticulated Siren

Siren reticulata

Graham, Kline, Steen & Kelehear, 2018

DOI: 10.1371/journal.pone.0207460 

 photos: Pierson Hill   twitter.com/AlongsideWild

Abstract

The salamander family Sirenidae is represented by four extant species that are restricted to North America. Sirens are abundant throughout the southern United States and are among the world’s largest amphibians, yet the biology, ecology, and phylogeography of this group is poorly-known. In this study we use morphological and genetic evidence to describe a previously unrecognized species from southern Alabama and the Florida panhandle. We name this species the Reticulated Siren, Siren reticulata. Future studies will enable more precise phylogenetic information about S. reticulata and will almost surely reveal additional undescribed species within the family.

    

Fig 1. (A) Siren reticulata paratype specimen captured in Okaloosa County, Florida.
(B) Location of Siren reticulata captured in 2009 by D. Steen and M. Baragona.
(C) The type locality of Siren reticulata, Walton County, Florida.

Siren reticulata, sp. nov.

Reticulated Siren

Etymology: This animal has been colloquially referred to as the Leopard Eel. However, given that the species is neither a leopard nor an eel, we selected Reticulated Siren as a more appropriate formal common name. The specific name, reticulata, is a reference to the reticulated pattern typical of all specimens we examined.

Diagnosis: Like all Sirenids, S. reticulata has an elongate, eel-like body shape, two forelimbs, no eyelids, a lateral line, enlarged external gill fimbriae associated with gill slits, and a horny beak in place of the premaxillary teeth typical of other salamanders. There are only two known genera in the family Sirenidae: Pseudobranchus and Siren. The genus Pseudobranchus (dwarf sirens) includes two species (restricted to Florida, southern Georgia, and South Carolina) and is diagnosed by the presence of only one gill slit and three digits on each limb. The species we describe herein is assigned to the genus Siren based upon its large size, presence of four digits on the forelimbs, and three permanent gill fimbriae with three associated external gill slits. The dorsum of S. reticulata is olive-grey with lighter yellow-green flanks. It has an obvious and striking dark reticulate spotted pattern beginning at the gill arches and continuing to the tail (Fig 1A). Some specimens show a decided boundary where the spotting pattern ends along the flanks, while others show continuous spotting along the flanks that continue onto the ventral surface. The venter is a lighter olive green-yellowish color and in some specimens, it is also sparsely covered with irregular spots.

.....

Fig 3. Bayesian inference consensus tree for sirens and Pseudobranchus axanthus outgroup using five gene sequences: CytB, COI, ND5, 12S and 16S. The tree was generated in MrBayes and run for 5 million generations using a partition scheme determined using Partition Finder 2. The top number is probability generated in MrBayes. The bottom number is the maximum likelihood % from 1,000 bootstraps generated in RAxML. Accession numbers are in Table 2.

Life history and ecology: Due to the difficulty in acquiring specimens and this species’ apparently limited distribution, little is known of S. reticulata life history and ecology. Clearly, research on this topic is an urgent need. Most of what we know of this species is consistent with the general habits of other described species of sirens. The holotype contains hundreds of tiny developing follicles, suggesting that females have high fecundity, a feature also exhibited by S. lacertina. Mating, fertilization mode (e.g., external or internal), nests, and eggs are undescribed. However, we emphasize that this information is scarce even for long-recognized S. lacertina or S. intermedia.

Sean P. Graham, Richard Kline, David A. Steen and Crystal Kelehear. 2018. Description of An Extant Salamander from the Gulf Coastal Plain of North America: The Reticulated Siren, Siren reticulata.  PLoS ONE. 13(12): e0207460.  DOI: 10.1371/journal.pone.0207460  

 twitter.com/AlongsideWild/status/1070392572877524993

New species of giant salamander discovered in Florida on.natgeo.com/2E4tI2n via @NatGeo

   

[PaleoMammalogy • 2018] Maiabalaena nesbittae • Tooth Loss Precedes the Origin of Baleen in Whales

Maiabalaena nesbittae 

 Peredo, Pyenson, Marshall & Uhen, 2018

  DOI: 10.1016/j.cub.2018.10.047

 Illustration: Alex Boersma (AlexBoersma.com)

 twitter.com/CMPeredo

Highlights

• Maiabalaena nesbittae is 33 million year old fossil baleen whale from Oregon

• Maiabalaena has neither teeth, nor baleen

• Early whales lost teeth entirely before the evolutionary origin of baleen

• Despite no teeth or baleen, these whales were effective suction feeders

Summary

Whales use baleen, a novel integumentary structure, to filter feed; filter feeding itself evolved at least five times in tetrapod history but demonstrably only once in mammals. Living baleen whales (mysticetes) are born without teeth, but paleontological and embryological evidence demonstrate that they evolved from toothed ancestors that lacked baleen entirely. The mechanisms driving the origin of filter feeding in tetrapods remain obscure. Here we report Maiabalaena nesbittae gen. et sp. nov., a new fossil whale from early Oligocene rocks of Washington State, USA, lacking evidence of both teeth and baleen. The holotype possesses a nearly complete skull with ear bones, both mandibles, and associated postcrania. Phylogenetic analysis shows Maiabalaena as crownward of all toothed mysticetes, demonstrating that tooth loss preceded the evolution of baleen. The functional transition from teeth to baleen in mysticetes has remained enigmatic because baleen decays rapidly and leaves osteological correlates with unclear homology; the oldest direct evidence for fossil baleen is ∼25 million years younger than the oldest stem mysticetes (∼36 Ma). Previous hypotheses for the origin of baleen are inconsistent with the morphology and phylogenetic position of Maiabalaena. The absence of both teeth and baleen in Maiabalaena is consistent with recent evidence that the evolutionary loss of teeth and origin of baleen are decoupled evolutionary transformations, each with a separate morphological and genetic basis. Understanding these macroevolutionary patterns in baleen whales is akin to other macroevolutionary transformations in tetrapods such as scales to feathers in birds.

Keywords: baleen, cetacea, filter-feeding, mysticeti, suction feeding

Figure 1. Cranial Elements of the Holotype of Maiabalaena nesbittae, USNM 314627.

Systematics 

Cetacea; Pelagiceti; 

Neoceti; Mysticeti; 

Maiabalaena nesbittae gen. et sp. nov. 

Etymology: Maiabalaena combines Maia-, meaning mother, and -balaena, meaning whale. Named for its phylogenetic position as basal to baleen-bearing mysticetes. The specific epithet nesbittae honors Dr. Elizabeth A. Nesbitt for her lifetime of contribution to paleontology of the Pacific Northwest and her mentorship and collegiality at the Burke Museum of Natural History and Culture in Seattle, Washington, USA.

 3D models of select specimens in lateral view with artistic reconstructions of their feeding modes:
 (B) Basilosaurus isis; (C) Coronodon havensteini; (D) Maiabalaena nesbittae; and (E) Balaenoptera musculus.

These panels illustrate the loss of a functional dentition, the intermediate phase with neither teeth nor baleen, and the subsequent origin of baleen. Illustrations are original artwork by Alex Boersma (www.alexboersma.com).

Figure 2. Phylogenetic Relationships of Stem Mysticetes Illustrating the Evolutionary Loss of Teeth and Subsequent Origin of Baleen Figure illustrates a composite phylogeny including results from this analysis (Figure S4) and recently published analyses.
(A) Time calibrated simplified phylogeny, with collapsed clade resolution for Mammalodontidae, Aetiocetidae and Eomysticetidae, and crown Mysticeti.
 (B–E) Colored bars indicate groups figured; gray bars indicate groups not figured. Panels (b–e) represent 3D models of select specimens in lateral view with artistic reconstructions of their feeding modes: (B) Basilosaurus isis; (C) Coronodon havensteini; (D) Maiabalaena nesbittae; and (E) Balaenoptera musculus. These panels illustrate the loss of a functional dentition, the intermediate phase with neither teeth nor baleen, and the subsequent origin of baleen. Illustrations are original artwork by Alex Boersma (www.alexboersma.com).

This is an artistic reconstruction of a mother and calf of Maiabalaena nesbittae nursing offshore of Oregon during the Oligocene, about 33 million years ago. While Maiabalaena would not have been able to chew or filter feed, muscle attachments on the bones of its throat indicate it likely had strong cheeks and a retractable tongue. These traits would have enabled it to suck water into its mouth, taking up fish and small squid in the process. The ability to suction feed would have rendered teeth, whose development requires a lot of energy to grow, unnecessary. The loss of teeth, then, appears to have set the evolutionary stage for the baleen, which the scientists estimate arose about 5 to 7 million years later.

 Illustration: Alex Boersma (www.alexboersma.com)

 Carlos Mauricio Peredo, Nicholas D. Pyenson, Christopher D. Marshall and Mark D. Uhen. 2018. Tooth Loss Precedes the Origin of Baleen in Whales. Current Biology.  DOI: 10.1016/j.cub.2018.10.047

 twitter.com/CMPeredo/status/1068179652135534592

 twitter.com/CMPeredo/status/1068229477375901696

 twitter.com/PyensonLab/status/1068215385613324290

twitter.com/NMNH/status/1068184159632453634

Whales Lost Their Teeth Before Evolving Hair-like Baleen in Their Mouths  si.edu/newsdesk/releases/whales-lost-their-teeth-evolving-hair-baleen-their-mouths via @Smithsonian

Toothless, 33-Million-Year-Old Whale Could Be an Evolutionary ‘Missing Link’  gizmodo.com/toothless-33-million-year-old-whale-could-be-an-evolut-1830739126 via @gizmodo

    

[Cnidaria • 2018] Alaskagorgia splendicitrina • An Unusual New Gorgonian (Anthozoa: Octocorallia: Plexauridae) from the Aleutian Islands of Alaska

Alaskagorgia splendicitrina

Horvath & Stone, 2018

 DOI:  10.11646/zootaxa.4524.1.8 

Abstract
An unusual new species of plexaurid octocoral, Alaskagorgia splendicitrina, is described from a specimen collected in the far west Aleutian Island Archipelago, Alaska, USA. Unusual features that separate it from its only congener include: the vibrant yellow color of the live colony and an arborescent growth form with numerous coiling and twisting branches, the pale yellow color of the sclerites and the lack of small and densely warted double-headed sclerites. The new species is represented by only a single specimen despite extensive sampling in the region during the past several decades; the speculation is that it radiated from the much less explored region to the west.

Keywords: Coelenterata, Taxonomy, new species, cold-water coral, subarctic, Aleutian Islands

Holotype of Alaskagorgia splendicitrina n. sp. Whole, live colony upon collection. 

Taxonomy 

Class Octocorallia
Suborder Holaxonia
Family Plexauridae Gray, 1859

 Genus Alaskagorgia Sánchez and Cairns, 2004

Alaskagorgia splendicitrina sp. nov.

Etymology. The species designation is derived from the Latin word for “bright” or “vibrant” (=splendius) and the Latin for “lemon-yellow” (=citrina).
 Common name. Lemon-yellow Squat Gorgonian.

Type locality. Stalemate Bank, western Aleutian Islands, .... 184 m.


Elizabeth A. Horvath and Robert P. Stone. 2018. Another Unusual New Gorgonian (Anthozoa: Octocorallia: Plexauridae) from the Aleutian Islands of Alaska. Zootaxa. 4524(1); 112–120. DOI:  10.11646/zootaxa.4524.1.8

[Paleontology • 2018] Gordodon kraineri • The Oldest Specialized Tetrapod Herbivore: A New Eupelycosaur from the Permian of New Mexico, USA

Gordodon kraineri 

Lucas, Rinehart & Celeskey, 2018

  DOI: 10.26879/899 

 palaeo-electronica.org 

ABSTRACT

Gordodon kraineri is a new genus and species of edaphosaurid eupelycosaur known from an associated skull, lower jaw and incomplete postcranium found in the early Permian Bursum Formation of Otero County, New Mexico, USA. It has a specialized dental apparatus consisting of large, chisel-like incisors in the front of the jaws separated by a long diastema from relatively short rows of peg-like maxillary and dentary cheek teeth. The dorsal vertebrae of Gordodon have long neural spines that bear numerous, randomly arranged, small, thorn-like tubercles. The tubercles on long neural spines place Gordodon in the Edaphosauridae, and the dental apparatus and distinctive tubercles on the neural spines distinguish it from the other edaphosaurid genera—Edaphosaurus, Glaucosaurus, Lupeosaurus and Ianthasaurus. Gordodon is the oldest known tetrapod herbivore with a dentary diastema, extending the temporal range of that anatomical feature back 95 million years from the Late Triassic. The dental apparatus of Gordodon indicates significantly different modes of ingestion and intraoral transport of vegetable matter than took place in Edaphosaurus and thus represents a marked increase in disparity among edaphosaurids. There were two very early pathways to tetrapod herbivory in edaphosaurid evolution, one toward generalized browsing on high-fiber plant items (Edaphosaurus) and the other (Gordodon) toward more specialized browsing, at least some of it likely on higher nutrient, low fiber plant items. Gordodon shows a surprisingly early specialization of the dental apparatus and indicates how incomplete our knowledge is of edaphosaurid evolution, disparity and diversity.

FIGURE 2. Holotype skull, lower jaw and incomplete postcranium of Gordodon kraineri, NMMNH P-70796, photograph (1) and bone map (2). Scale equals 10 cm.

FIGURE 3. The skull and lower jaw, as preserved, of the holotype of Gordodon kraineri, NMMNH P-70796, in right lateral view, photograph (1) and line drawing (2). 

Anatomical abbreviations are: an = angular; ar = articular; d = dentary; ep = epipterygoid; f = frontal; l = lacrimal; m = maxilla; mtp = mandibular tooth plate; n = nasal; p = parietal; pf = postfrontal; pm = premaxilla; pr = prearticular; prf = prefrontal; pt = pterygoid; q = quadrate; qj = quadratojugal; sa = surangular; sm = septomaxilla; spl = splenial; sq = squamosal; st = supratemporal; t = tabular; v = vomer. Scale equals 1 cm.

SYSTEMATIC PALEONTOLOGY

SYNAPSIDA Osborn, 1903

EUPELYCOSAURIA Kemp, 1982

EDAPHOSAURIDAE Cope, 1882

Gordodon gen. nov.

Etymology. Gordo, Spanish for “fat,” and Greek odon, “tooth,” in reference to the large (“fat”) teeth at the anterior end of the snout of the holotype. Gordo also is a reference to the city of Alamogordo, near the type locality.

Diagnosis. Gordodon is a medium-sized edaphosaur (presacral length ~1 m) distinguished from the other edaphosaurid genera by: an unique dental apparatus consisting of large chisel-like incisors in the premaxilla and dentary (dentary incisors inferred from empty alveolus) separated by a long diastema from a relatively short row of peg-like maxillary and dentary cheek teeth and tooth plates with small (<1 mm) teeth on the interior surface of the mandible; preorbital skull length subequal to postorbital skull length; a relatively short nasal-maxilla suture; cervical and anterior dorsal vertebrae with relatively gracile centra that are double-keeled ventrally; and cervical and dorsal vertebrae have long neural spines that bear up to 12 small, thorn-like lateral tubercles randomly distributed on each side.

Gordodon kraineri sp. nov.

 Etymology. To honor Karl Krainer for his many contributions to our knowledge of the late Paleozoic geology and paleontology of New Mexico.

Holotype. NMMNH P-70796, incomplete skeleton consisting of the skull, lower jaws, all or parts of 21 vertebrae (five cervical vertebrae, four complete dorsal vertebrae, the neural spines in varying states of completeness of 12 additional dorsal vertebrae), parts of five cervical and five dorsal rib pairs, parts of the right and left clavicles and scapulae and parts of two digits of the manus(?) (Figure 2).

Holotype locality. NMMNH locality 8967, Otero County, New Mexico, USA (Figure 1).

Stratigraphic horizon and age. Lower part of Bursum Formation, early Wolfcampian (early Permian).

....

 Life restoration of Gordodon kraineri.

Spencer G. Lucas, Larry F. Rinehart and Matthew D. Celeskey. 2018. The Oldest Specialized Tetrapod Herbivore: A New Eupelycosaur from the Permian of New Mexico, USA.   Palaeontologia Electronica. 21.3.39A; 1-42.  DOI: 10.26879/899  

palaeo-electronica.org/content/2018/2343-new-eupelycosaur

Plain Language Abstract: Gordodon kraineri is a new kind of sail-backed reptile based on an incomplete skeleton found in ~300 million year old rocks in southeastern New Mexico. Gordodon belongs to a family of early herbivorous reptiles, the Edaphosauridae, and has a surprisingly specialized skull and dentition. These skeletal specializations indicate it was a selective browser on plants.

[PaleoOrnithology • 2018] Mirarce eatoni • The Most Complete Enantiornithine (Aves, Ornithothoraces) from North America and A Phylogenetic Analysis of the Avisauridae

Mirarce eatoni 

Atterholt​, Hutchison & O’Connor, 2018

DOI: 10.7717/peerj.5910

 Illustration: Brian Engh. 

Abstract

The most complete known North American enantiornithine was collected in 1992 but never formally described. The so-called “Kaiparowits avisaurid” remains one of the most exceptional Late Cretaceous enantiornithine fossils. We recognize this specimen as a new taxon, Mirarce eatoni (gen. et sp. nov.), and provide a complete anatomical description. We maintain that the specimen is referable to the Avisauridae, a clade previously only known in North America from isolated tarsometatarsi. Information from this specimen helps to clarify evolutionary trends within the Enantiornithes. Its large body size supports previously observed trends toward larger body mass in the Late Cretaceous. However, trends toward increased fusion of compound elements across the clade as a whole are weak compared to the Ornithuromorpha. The new specimen reveals for the first time the presence of remige papillae in the enantiornithines, indicating this feature was evolved in parallel to dromaeosaurids and derived ornithuromorphs. Although morphology of the pygostyle and (to a lesser degree) the coracoid and manus appear to remain fairly static during the 65 million years plus of enantiornithine evolution, by the end of the Mesozoic at least some enantiornithine birds had evolved several features convergent with the Neornithes including a deeply keeled sternum, a narrow furcula with a short hypocleidium, and ulnar quill knobs—all features that indicate refinement of the flight apparatus and increased aerial abilities. We conduct the first cladistic analysis to include all purported avisuarid enantiornithines, recovering an Avisauridae consisting of a dichotomy between North and South American taxa. Based on morphological observations and supported by cladistic analysis, we demonstrate Avisaurus to be paraphyletic and erect a new genus for “A. gloriae,” Gettyia gen. nov.

Figure 2:  Mirarce eatoni, A sampling of the best-preserved cervical and thoracic vertebrae, including the axis.
 (A) Axis in lateral view. (B) Axis in dorsal view. (C) Axis in caudal view. (D) Third cervical vertebra in lateral view. (E) Third cervical vertebra in ventral view. (F) Posterior cervical vertebra in lateral view. (G) Posterior cervical vertebra in ventral view. (H) Thoracic vertebra in lateral view. (I) Thoracic vertebra in ventral view. (J) Thoracic vertebra in anterior view.

 Abbreviations: ds, dens; ep, epipophysis; lg, lateral groove; lr, lateral ridge; pap, parapophysis; prz, prezygopophysis; poz, postzygopophysis; ps, posterior shelf; sp, spinous process; vp, ventral process. Scale bar equals one cm. 

Photos: David Strauss.

 Figure 19: A skeletal reconstruction of Mirarce eatoni showing preserved skeletal elements (white).

Illustration: Scott Hartman.

Systematic paleontology

Class AVES Linnaeus, 1758

ORNITHOTHORACES Chiappe, 1995

Subclass ENANTIORNITHES Walker, 1981

Family AVISAURIDAE Brett-Surman and Paul, 1985

Revised diagnosis: Enantiornithine birds with the following unique combination of morphological features: tarsometatarsus with inclined proximal articular surface; strong transverse convexity of the dorsal surface of the mid-shaft of metatarsal III; a distinct plantar projection of the medial rim of the trochlea of metatarsal III (unambiguously supported in our phylogenetic analysis); and a laterally compressed J-shaped metatarsal I (modified from Chiappe (1993)).

Phylogenetic definition: the last common ancestor of Neuquenornis volans and Avisaurus archibaldi plus all its descendants (Chiappe, 1993).

Included genera: Avisaurus (Brett-Surman & Paul, 1985); Soroavisaurus (Chiappe, 1993); Neuquenornis (Chiappe & Calvo, 1994); Intiornis (Novas, Agnolín & Scanferla, 2010); Mirarce (current study); and Gettyia (current study).

MIRARCE GEN. NOV.

Etymology: Named for its spectacular preservation and level of morphological detail (Latin “mirus” for wonderful), and after Arce, winged messenger of the titans in Greek mythology, for the evidence suggesting a refined flight apparatus in this species.

Type species: Mirarce eatoni sp. nov. (by monotypy)

Etymology: The type species is named in honor of Dr. Jeffrey Eaton, for his decades of work contributing to our understanding of the Kaiparowits Formation and the fossils recovered from it.

MIRARCE EATONI SP. NOV

Holotype: UCMP 139500, a three-dimensional partial skeleton consisting of several cervical and thoracic vertebrae (including the axis), the pygostyle, almost all phalanges from the left pes and several from the right, a complete humerus, femur, and tarsometatarsus, a partial scapula, coracoid, furcula, and tibiotarsus, as well as fragments of the sternum, radius, ulna, carpometacarpus, and manual phalanges (see Table 1 for measurements of select elements).

Type horizon and locality: UCMP locality V93097, Late Cretaceous (late Campanian 76–74.1 Ma; Roberts, Deino & Chan, 2005) Kaiparowits Formation of Grand Staircase-Escalante National Monument in Garfield County, Utah, USA.

Diagnosis. A large, turkey-sized avisaurid (see above diagnosis) enantiornithine (thoracic vertebrae with centrally located parapophyses; pygostyle cranially forked with ventrolateral processes; furcula dorsolaterally excavated; Chiappe & Walker, 2002) with the following autapomorphies: posterior end of sternum weakly flexed caudodorsally, terminating in a small knob; ulnae with remige papillae present; small, deep, circular pit located just craniolateral to the femoral posterior trochanter; small, triangular muscle scar on medial margin of the femoral shaft just distal to the head followed distally by a much larger proximodistally elongate oval; distinct, rugose ridge-like muscle attachment located on the craniomedial margin of the femur a quarter length from the distal end; and tubercle for the m. tibialis cranialis located at the mid-point of the shaft of metatarsal II on the dorsal surface. The new species is further distinguished by the unique combination of the following characters: acrocoracoidal tubercle very weakly developed and medially located; furcula with truncate (untapered) omal tips weakly developed into articular facets and oriented perpendicular to the axis of the rami; ventral projection of the sternal keel proportionately greater than in most other enantiornithines (similar to condition observed in Neuquenornis); acetabulum fully perforate; medial surface of the medial condyle of the tibiotarsus with deep circular excavation; and elongate, slightly raised, flat, oval surface present on the medial edge of the plantar surface of metatarsal II continuous with a weak medial plantar crest.

Figure 20: A reconstruction of living Mirarce eatoni, illustrating the large body size of this taxon.

 Illustration: Brian Engh.

  

Revised Systematic Paleontology

GETTYIA GEN. NOV.

Etymology: Named in honor of Mike Getty, a great friend, technician, and field paleontologist, who is dearly missed.

GETTYIA GLORIAE (Varricchio & Chiappe, 1995) new comb.

Holotype: MOR 553E/6.19.91.64, a three-dimensional tarsometatarsus missing part of metatarsal IV.

Type horizon and locality: Upper Cretaceous (Campanian) Two Medicine Formation, MOR locality TM-068, Glacier County, Montana, USA.

Diagnosis: small avisaurid enantiornithine with the following unique combination of features: dorsal surface of the tarsometatarsus strongly inclined; attachment for the m. tibialis cranialis located beyond the midpoint of the tarsometatarsus; and distal vascular foramen completely closed by metatarsal IV.

Jessie Atterholt​, J. Howard Hutchison and Jingmai K. O’Connor. 2018. The Most Complete Enantiornithine from North America and A Phylogenetic Analysis of the Avisauridae. PeerJ. 6:e5910.  DOI: 10.7717/peerj.5910