[PaleoMammalogy • 2025] Salwasiren qatarensis • High Abundance of Early Miocene Sea Cows (Sirenia: Dugongidae) from Qatar shows repeated Evolution of Seagrass Ecosystem Engineers in Eastern Tethys

  

 Salwasiren qatarensis 

Pyenson​, Sakal, LeBlanc, Blundell, Klim, Marshall, Velez-Juarbe, Wolfe & Al-Naimi, 2025

 

DOI: doi.org/10.7717/peerj.20030

Artwork: Alex Boersma

Abstract 

Coastal ecosystems that include seagrasses are potential carbon sinks that require strategic conservation of top trophic consumers, such as dugongs, to maintain their function. It is unclear, however, how long seagrass ecosystems have persisted in geologic time because their fossil record is poor, although the record of their associated vertebrate consumers offers useful proxies. Here we describe an area of dense Early Miocene dugongid remains from Qatar. We documented over 172 sites in <1 km2 from one stratigraphic level, including material representing a new species of fossil dugongine dugongid. This taxon is unrelated to coeval Early Miocene dugongids from India and the Eastern Tethys and it is distantly related to extant dugongs, which occupy seagrass habitats of the Persian or Arabian Gulf (hereafter ‘Gulf’) today. The monodominant assemblage in this area likely reflects a single fossil dugongid taxon and matches the ecological diversity and geospatial distribution of modern-day live-dead assemblages in the Gulf. This fossil site from Qatar shows that the Gulf has repeatedly evolved sea cow communities with different taxa over the past 20 million years and coincides with an Early Miocene marine biodiversity hotspot in Arabia, prior to its eastward shift to the Indo-Australian Archipelago where dugongs continue to thrive today.

Keywords: Marine mammal, Paleoecology, Seagrasses, Evolution, Fossil record

Mammalia Linnaeus, 1758

Afrotheria Stanhope et al., 1998

Tethytheria McKenna, 1975

Sirenia Illiger, 1811 sensu Vélez-Juarbe & Wood, 2018

Dugongidae Gray, 1821 sensu Vélez-Juarbe & Wood, 2018

Dugonginae Gray, 1821 (Simpson, 1932) sensu Vélez-Juarbe & Wood, 2018

 Salwasiren qatarensis morphology using 3D photogrammetry of μCT of key skeletal elements.
(A–C) holotype cranium including left premaxilla, jugal, and partial braincase; (D–F) referred left incisor; (G–H) holotype left upper M2, in mesial and occlusal views, respectively; (I) holotype incomplete left mandible; (J–M) holotype lumbar, sacral, and caudal vertebrae in anterior views with left ilium (L) in lateral view; and (N–O) holotype right humerus.

Abbreviations: a, acetabulum; ac, anterior cingulum; acv, anterior cingular valley; an, angular process; co, coronoid process; cc, coronoid canal; dc, deltoid crest; f, frontal; gt, greater tubercle; h, humeral head; it, ischial tuberosity; j, jugal; lt, lesser tubercle; mcl+hy, metaconule + hypocone; me, metacone; ns, neural spine; p, parietal; pa, paracone; pmx, premaxilla; pr, protocone; ptp, posttympanic process; so, supraoccipital; sop, supraorbital process; sq, squamosal; tp, transverse process; tr, trochlea; zp, zygomatic process.

Salwasiren qatarensis gen. et sp. nov.

Type locality, horizon, and age: Al Maszhabiya bonebed, Lower Al-Kharrara Member of the Dam Formation, Aquitanian, 23.03–21.6 Ma.

Differential diagnosis: Salwasiren is a dugongine distinguished from other sirenians by the following combination of characters: nasal process of the premaxilla long, thin and tapering at posterior end (c.6[0], 7[0]) as in Crenatosiren olseni and Dugong dugon; supraorbital process of frontal dorsoventrally thick with a weakly developed posterolateral corner (c.36[1]), as in C. olseni and D. dugon; deep and narrow nasal incisure (c.37[1]) as in most dugongines; flat frontal roof (c.42[0], as in C. olseni, Italosiren bellunensis and Bharatisiren indica; supraoccipital wider ventrally than dorsally (c.23[1]) and exoccipitals not meeting along a dorsal suture (c.66[1]), as in Nanosiren spp. and D. dugon; ventral extremity of jugal under posterior edge of orbit (c.85[1]) and flat, thin preorbital process of jugal (c.88[0]), shared with C. olseni and Nanosiren spp.; short zygomatic process of the jugal (c.89[1]), as in Dioplotherium manigaulti and Xenosiren yucateca; ventral rim of orbit that does not overhang the lateral surface (c.90[0]), as in I. bellunensis and Callistosiren boriquensis; mandible with broad, subrectangular symphysis (c.121[3]); I1 alveolus small (c.140[0]) as in Nanosiren spp.; I1 with suboval cross section and enamel on all sides (c.141[0], 142[0]), as in C. olseni and N. sanchezi; pubis prong-like without symphysis (c.215[2]).

Etymology: “Salwa” after the Bay of Salwa, part of the transboundary habitat for dugongs in the Gulf combined with the Latin “siren”, referring to Sirenia. The species epithet honors its discovery in the State of Qatar.

 

Nicholas Pyenson, the curator of fossil marine mammals at the Smithsonian's National Museum of Natural History, and Ferhan Sakal, an archaeologist who is the head of excavation and site management at Qatar Museums, survey Al Maszhabiya with the fossil ribs of a 21-million-year-old sea cow in the foreground.

photo by Clare Fieseler

An artistic reconstruction of a herd of Salwasiren qatarensis sea cows foraging on the seafloor. In southwest Qatar, fossils of a new species of ancient sea cow, Salwasiren qatarensis, were found in 21-million-year-old rocks along with evidence of extinct sharks, barracuda-like fish, prehistoric dolphins and sea turtles.

Artwork: Alex Boersma

Nicholas D. Pyenson​, Ferhan Sakal, Jacques LeBlanc, Jon Blundell, Katherine D. Klim, Christopher D. Marshall, Jorge Velez-Juarbe, Katherine Wolfe and Faisal Al-Naimi. 2025. High Abundance of Early Miocene Sea Cows from Qatar shows repeated Evolution of Seagrass Ecosystem Engineers in Eastern Tethys.  PeerJ. 13:e20030. DOI: doi.org/10.7717/peerj.20030 [December 10, 2025]

https://www.smithsonianmag.com/smart-news/a-trove-of-sea-cow-fossils-in-qatar-reveals-a-new-species-that-munched-on-seagrass-21-million-years-ago-180987820/

[PaleoMammalogy • 2025] Megabalaena sapporoensis • A New member of a large and archaic balaenid (Mysticeti: Balaenidae) from the Late Miocene of Sapporo, Hokkaido, Japan partly fills a gap of Right Whale Evolution

Megabalaena sapporoensis

Tanaka, Kimura, Shinmura, Ohira & Furusawa, 2025

DOI: doi.org/10.26879/1549 

 Artwork by Tatsuya Shinmura 

ABSTRACT

The family Balaenidae (right whales) includes two genera and four extant species, all of which are endangered and giant animals measuring approximately 17 to 20 m in length. The history of the Balaenidae spans about 20 million years. Several small sized extinct balaenids from the Pliocene have been identified. However, half of this history remains unknown owing to a 9-million-year gap from 15.2 to 6.1 m.y.a. in the fossil record. A well-preserved fossil balaenid skeleton, designated SMAC 2731, from the Late Miocene approximately 9 m.y.a. in Sapporo, Hokkaido, Japan, is named as Megabalaena sapporoensis gen. et sp. nov. This specimen preserves the skull, periotics in situ, tympanic bullae, right mandible, basihyal-thyrohyal, right stylohyal, sternum, seven cervical vertebrae, nine thoracic vertebrae, and 16 more posterior vertebrae, rib fragments, scapulae, and left forelimb elements. All preserved vertebral epiphyses are fused, indicating that SMAC 2731 was physically mature. Notably, M. sapporoensis can be distinguished from other balaenids by its excavated orbit in dorsal view with a large postorbital process, dorsoventrally high anterior part of the involucrum of the tympanic bulla, long compound posterior process, high coronoid process and deeper subcondylar furrow of the mandible, incipient cervical fusion (C2+C3 only), and its slender forelimb bones, including the humerus, radius and ulna. Based on a bizygomatic width of 2.2 m, the estimated total length of the holotype of M. sapporoensis is 12.7 m. Overall, M. sapporoensis indicates that balaenids diversified prior to the Late Miocene.

   

Keywords: Balaenidae;  new genus;  new species;  Tortonian;  gigantism;  Japan

Forelimb elements of balaends. 
Megabalaena sapporoensis (A),
Charadrobalaena valentinae, outline taken from Bisconti et al. (2023) and is a mirror image (B),
Antwerpibalaena liberatlas, outline taken from Duboys de Lavigerie et al. (2020) and is a mirror image (C),
Eubalaena japonica, outline taken from Omura (1958) (D), and are not to scale.

  Images based on a 3D model showing preserved skull elements of SMAC 2731, Megabalaena sapporoensis. Deformations are not restored.

 Images based on a 3D model showing skull elements of SMAC 2731, Megabalaena sapporoensis in left lateral view (A) and dorsal view (B). Deformations are restored using 3D model editor by T. Shinmura. Settings are the same to Figure 3.

CETACEA Brisson, 1762

NEOCETI Fordyce and de Muizon, 2001

MYSTICETI Gray, 1864

CHAEOMYSTICETI Mitchell, 1989

BALAENIDAE Gray, 1825

Megabalaena gen. nov 

Type species. Megabalaena sapporoensis sp. nov.

Etymology. The generic name, Megabalaena , is named derived from ancient Greek megas meaning great, large and mighty, and the type genus name of the family Balaenidae.

 

Megabalaena sapporoensis sp. nov.

Locality and horizon. SMAC 2731 was found at a riverbed of Toyohira River in Sapporo City, Hokkaido, Japan, by Kazuhisa Mori on 10 October 2008: Latitude 42°58'1.24"N, longitude 141°13'18.01"E (Figure 1 and Figure 2). SMAC 2731 was found from the upper part of the Toyama Formation. At the fossil area, the diatomaceous siltstone Toyama Formation is distributed. Diatomaceous siltstone of the Toyama Formation is exposed at the type locality ...

Etymology. Named after the fossil locality, Sapporo City.

Diagnosis. Megabalaena sapporoensis is a member of the Balaenidae because it has a combination of these character states such as a posteriorly pointed anterior edge of the supraorbital process lateral to the ascending process of the maxilla with the skull in dorsal view (Character 31, state 0), laterally oriented postorbital process in dorsal view (Character 38, state 1), confluent posterior border of the zygomatic process of the squamosal and exoccipital in dorsal view (Character 67, state 1), dorsoventrally higher than long parietal in lateral view (Character 76, state 1), anterolaterally directed zygomatic process of the squamosal in dorsal view (Character 86, state 2), distinctly higher than long squamosal including the zygomatic and postglenoid processes (Character 92, state 1), short squamosal fossa (Character 96, state 1), foramen pseudovale opening posteriorly between the squamosal and pterygoid (Character 118, state 1), and posteriorly diverging basioccipital crests in ventral view (Character 125, state 0).

..

 Restoration of Megabalaena sapporoensis by Tatsuya Shinmura (Ashoro Museum of Paleontology).

Yoshihiro Tanaka, Toshiyuki Kimura, Tatsuya Shinmura, Hiroto Ohira, and Hitoshi Furusawa. 2025. A New member of a large and archaic balaenid from the Late Miocene of Sapporo, Hokkaido, Japan partly fills a gap of Right Whale Evolution.  Palaeontologia Electronica. 28(2): a37. DOI: doi.org/10.26879/1549 [August 2025]

palaeo-electronica.org/content/2025/5581-archaic-balaenid-from-japan

  

Plain Language Abstract: The right whale family (Balaenidae) includes four extant species in two genera such as the Balaena and Eubalaena, all of which are endangered and giant animals about 17 to 20 m in length. The history of the right whale group spans about 20 million years. Several small-sized extinct fossil right whales from the Pliocene have been identified. However, half of this history remains unknown owing to a 9-million-year gap from 15.2 to 6.1 million years ago in the fossil record. A well-preserved fossil right whale skeleton (SMAC 2731) from the late Miocene (approximately 9 m.y.a.) of Sapporo, Hokkaido, Japan, is named as the new species Megabalaena sapporoensis. This specimen preserves the skull, ear bones, right lower jaw, hyoid bones, sternum, back bones, ribs, scapulae, and left forelimb elements. All preserved vertebral epiphyses are fused, indicating that SMAC 2731 was physically mature. Notably, M. sapporoensis can be distinguished from other balaenids by its large postorbital process of the skull and unfused cervical vertebrae, except for the axis and third cervical vertebra, and its slender forelimb long bones, including the humerus, radius and ulna, which are about twice slenderer than these of extant balaenids. Based on a bizygomatic width of 2.2 m, the estimated total length of the holotype of M. sapporoensis is 12.7 m. Overall, M. sapporoensis enhances our understanding of balaenid diversity, suggesting that it expanded earlier than the late Miocene.

[PaleoMammalogy • 2025] Janjucetus dullardi • An Immature Toothed Mysticete from the Oligocene of Australia and insights into mammalodontid (Mysticeti: Mammalodontidae) Morphology, Systematics, and Ontogeny

 

Janjucetus dullardi 

Duncan, Rule, Park, Evans, Adams & Fitzgerald, 2025

DOI: doi.org/10.1093/zoolinnean/zlaf090 

  x.com/Inxcetus

Abstract

Mammalodontids are a clade of toothed mysticetes known only from the Chattian of south-eastern Australia and New Zealand. Despite three named species (Janjucetus hunderi, Mammalodon colliveri, and Mammalodon hakataramea), the majority of mammalodontid material, largely represented by isolated teeth and ear bones found within the Torquay Basin (Victoria, Australia), remains undescribed. Here we describe a new species of mammalodontid, Janjucetus dullardi sp. nov., from the Jan Juc Marl. The holotype was found stratigraphically lower than M. colliveri and has morphology consistent with an immature stage of growth, plus near-unworn dental morphology. We identify a correlation between occipital condyle breadth and bizygomatic width and propose equations that permit us to estimate bizygomatic width and, subsequently, a body size estimate similar to the smallest known toothed mysticetes of ∼2.05–2.18 m. Phylogenetic analysis recovers J. dullardi as sister to J. hunderi within a monophyletic mammalodontid clade in all analyses. It also provides support for Mammalodontidae within Mysticeti, sister to an Aetiocetidae + Chaeomysticeti clade. Finally, revised diagnoses of Mammalodon and Janjucetus incorporating newly recogniszed tympanic and periotic characters permit the identification of isolated ear bones and inference of ontogenetic variation within Janjucetus.

Australia, Cetacea, Janjucetus, Mammalodon, Mammalodontidae, Mysticeti, Oligocene, ontogeny, phylogeny

Artist’s reconstruction of the complete skull of Janjucetus dullardi.
Parts preserved in the fossil are white and light grey.

 Art by Ruairidh Duncan

Janjucetus dullardi sp. nov. 

Etymology: The species name dullardi honours Mr Ross Dullard, who discovered the holotype.

Type locality, horizon, and age: The holotype of Janjucetus dullardi (NMV P256471) was discovered near the town of Jan Juc in the lowest beds of the exposed onshore Jan Juc Marl at Half Moon Bay, southwest of Bird Rock (Fig. 2) at approximately 38°21′03″S, 144°18′02″E (precise locality details are available on request). The lithology of this cliff face describes a neritic, inner mid-shelf environment, which coarsens upwards, and with relatively low abundance of infauna (Li et al. 1999, McLaren et al. 2009). The type of J. dullardi was found near the base of this outcrop, exposed beneath a wave-eroded overhang, slightly above the level of the tidal beach sands (Fig. 1). The lithology of this horizon [unit 1 and 2 of Reeckmann (1979)] is one of a silty, sandy grey marl, interspersed with bedding planes of coarse silts to fine sandstones and rich in glauconite. A horizon ∼3 m above the fossil-producing layer was aged to 24.67 Mya using strontium isotope ratios (Korasidis et al. 2018). The top of the Bells Headland outcrop, interpreted as ∼2 m stratigraphically lower than the base of the Bird Rock outcrop, was aged to 26.05 Mya at a point correlated to ∼2.5 m below the horizon containing NMV P256471 using the same methodology (Korasidis et al. 2018). We therefore give an estimated age of this specimen of between 24.67 and 26.05 Mya (middle Chattian).

Diagnosis: We interpret J. dullardi as a mammalodontid on the basis of: the presence of an involucral concavity on the medial surface of the tympanic bulla ventral to the involucral ridge; a dorsomedially extended and anteroposteriorly wide crista transversa, which reaches to the level of the rim of the internal acoustic meatus medially (also seen in Salishicetus and Coronodon); and the presence of apicobasal ridges on both the buccal and lingual surfaces of the tooth crowns (also seen in Morawanocetus, ­Coronodon, and Llanocetus).

This specimen shares the following features with J. hunderi to the exclusion of Mammalodon: an obliquely truncated rather than squared anterior margin of the tympanic bulla; an inner posterior prominence of the tympanic bulla mediolaterally broader than the outer posterior prominence at the widest point of the bulla; periotic body and posterior process greatly exceed the posterior margin of the fenestra rotunda; anteroposterior and dorsoventral diameters of the anterior process of the periotic are subequal to one another; and the mandibular posterior postcanine teeth lack a distal accessory shelf near the base of the crown.

...

Janjucetus dullardi calf and mother swimming through the shallow seas, 25 million years ago.

Art by Ruairidh Duncan

 

Ruairidh J Duncan, James P Rule, Travis Park, Alistair R Evans, Justin W Adams and Erich M G Fitzgerald. 2025. An Immature Toothed Mysticete from the Oligocene of Australia and insights into mammalodontid (Cetacea: Mysticeti) Morphology, Systematics, and Ontogeny. Zoological Journal of the Linnean Society. 204(4); zlaf090. DOI: doi.org/10.1093/zoolinnean/zlaf090 [12 August 2025] 

  x.com/Inxcetus/status/1955406875228508362

https://theconversation.com/a-cornucopia-of-tiny-bizarre-whales-used-to-live-in-australian-waters-heres-one-of-them-262806

[PaleoMammalogy • 2025] Eophyseter damarcoi • A New Pliocene Sperm Whale (Odontoceti: Physeteridae) from Vigliano D’Asti, Piedmont, Northwest Italy

 

 Eophyseter damarcoi 

Bisconti, Daniello, Stecca & Carnevale, 2025

DOI: doi.org/10.54103/2039-4942/22338

Abstract

A new sperm whale species is described from the late Zanclean (Early Pliocene) of Piedmont, northwest Italy, based on a partial vertebral column and parts of the forelimb. The new taxon, Eophyseter damarcoi gen. nov. sp. nov., is characterized by elongated vertebral centra in the thoracic and lumbar regions of the vertebral column, wider and higher articular facets for the occipital condyles in the atlas, elliptical and dorsoventrally compressed posterior articular facet of the axis-bearing block, ulna with posteriorly convex margin. These characters distinguish Eophyseter damarcoi gen. nov. sp. nov.from other physeteroids and show that the vertebral proportions are differently arranged with respect to those of the extant sperm whale species. A phylogenetic analysis was performed to understand the relationships of Eophyseter damarcoi gen. nov. sp. nov. by adding 20 postcranial characters to a previous character x taxon matrix; it revealed that E. damarcoi gen. nov. sp. nov. forms a clade with P. macrocephalus. A taphonomic analysis suggested that the carcass of the holotype specimen of Eophyseter damarcoi gen. nov. sp. nov. was exploited by sharks and colonized by barnacles and molluscs; however, a quick burial prevented its total destruction by other invertebrates, as usual in the cetacean fossil record from the Pliocene of Piedmont.

Keywords: Italy; Physeteridae; Phylogeny; Eophyseter; Physeteroidea; Piedmont; Pliocene; Postcranial skeleton.

Reconstruction of the sperm whale Eophyseter damarcoi gen. nov sp. nov. (MGPTPU 13864, holotype). 
 B) Piero Damarco, to whom Eophyseter damarcoi gen. nov. sp. nov. is dedicated, applying the final touch to the skeleton MGPT-PU 13864 on display in Asti.

Class MAMMALIA Linnaeus, 1758 

Order Cetacea Brisson, 1762 

Clade Neoceti Fordyce & Muizon, 2001 

Parvorder Odontoceti Flower, 1867 

Superfamily Physeteroidea Gray, 1868 

Family Physeteridae Gray, 1821 

Genus Eophyseter gen. nov.

Etymology: Eo is a Greek word (ήώς) that means dawn, meaning ancestral, old. Physeter derives from the Greek φυσώ meaning blower. Diagnosis of genus: Eophyseter damarcoi gen. nov. sp. nov. shows a unique morphology of the atlas, in the axis-bearing cervical block, in the proportions of the vertebral column and in the ulna. 

Diagnostic characters are the following: (1) the atlas is characterized by articular facets for the occipital condyles that protrude dorsally to the body of the vertebra and reach the height of the superior surface of the neural arch; (2) the articular surface for occipital condyles are comparatively wider than those of all the other physeteroids in which the atlas is preserved, and their ventromedial portion is comparatively longer; (3) in the axis-bearing cervical block, the epiphysis of the 7th cervical vertebra is dorsoventrally compressed and transversely widened to form showing an elliptical outline (it is transversely narrow and rounder in all the other physeteroids in which the axis-bearing block is preserved); (4) the lengths of the vertebral centra are comparatively more elongated than those of physeterids in which the vertebral column is known; in particular, in a long portion of the thoracic and lumbar regions of the vertebral column, the lengths of the centra are almost equal to the corresponding widths and heights (this pattern contrasts with that of extant sperm whales in which the length values are lower than those of heights and widths); (5) the posterior border of the ulna is posteriorly convex rather than being straight or concave as in other physeterids in which the ulna is preserved.

Eophyseter damarcoi gen. nov. sp. nov.

Etymology: The patronymic damarcoi is to honor Piero Damarco (Fig. 2B) who coordinated and executed extensive preparation of the specimen and who dedicated his life to the discovery and curation of the fossil treasures of Piedmont, Northwest Italy

 

Michelangelo Bisconti, Riccardo Daniello, Riccardo Stecca and Giorgio Carnevale. 2025. A New Pliocene Sperm Whale from Vigliano D’Asti, Piedmont, Northwest Italy. RIVISTA ITALIANA di PALEONTOLOGIA e STRATIGRAFIA. 131(1): 139-175. DOI: doi.org/10.54103/2039-4942/22338

[PaleoMammalogy • 2024] Romaleodelphis pollerspoecki • An archaic Dolphin from the Central Paratethys (Early Miocene, Austria)

Romaleodelphis pollerspoecki

Sanchez-Posada, Racicot, Ruf, Krings & Rössner, 2024 

DOI: 10.1080/02724634.2024.2401503 

www.LMU.de

 

ABSTRACT

A new long-snouted homodont odontocete fossil from the Lower Miocene of Austria (ca. 22.5–22.0 Ma) is formally described and interpreted based on external skull characteristics supplemented by CT and µCT data. The specimen was found in deposits from the Central Paratethys and includes an incomplete and fragmented cranium and mandible as well as ear bones. It differs markedly from previously identified long-snouted archaic dolphins with single-rooted, homodont dentition, and thus is suggestive of a new taxon, for which the name Romaleodelphis pollerspoecki proposed. The geological context of R. pollerspoecki hints at a neritic habitat in close vicinity to estuarine environments. Romaleodelphis pollerspoecki shares key features with certain members of the so-called ‘Chilcacetus clade’ such as the widening of the premaxillae at the rostrum base and the absence of a deep lateral groove along the rostrum; however, a phylogenetic analysis reconstructs R. pollerspoecki in a polytomy with members of this ‘clade’ and a larger clade including many other taxa. To better understand the phylogenetic relationships of these taxa, comprehensive reexamination of Argryocetus and Macrodelphinus will be necessary. Measurements obtained through µCT-based internal anatomical reconstruction of the bony labyrinth indicate that R. pollerspoecki had the ability to hear specialized high-frequency signals similar to modern narrow-band high-frequency (NBHF) specialists. This work further identifies several extinct platanistoids as hearing within the NBHF spectrum, increasing the understanding of the diversity of ecological adaptations in early-diverging odontocetes and providing more examples of convergent evolution of this hearing type.

Romaleodelphis pollerspoecki, gen. et sp. nov.

 

Catalina Sanchez-Posada, Rachel A. Racicot, Irina Ruf, Michael Krings and Gertrud E. Rössner. 2024. Romaleodelphis pollerspoecki, gen. et sp. nov., An archaic Dolphin from the Central Paratethys (Early Miocene, Austria). Journal of Vertebrate Paleontology.  e2401503. DOI: doi.org/10.1080/02724634.2024.2401503

Archaic dolphin could hear high frequency sounds

 www.LMU.de/en/newsroom/news-overview/news/archaic-dolphin-could-hear-high-frequency-sounds.html

[PaleoMammalogy • 2024] Miodelphinus miensis • A New platanistoid (Odontoceti: Squalodelphinidae) from the Early Miocene of Japan

Miodelphinus miensis

 Tanaka & Nakagawa, 2024

DOI: 10.1080/14772019.2024.2378783  

Abstract

Extant Ganges and Indus river dolphins are endangered species, but their relatives were more diverse in the past. The family Squalodelphinidae is a group of Miocene relatives of Ganges and Indus river dolphins. Our knowledge of squalodelphinids increased slowly in the nineteenth century and has expanded dramatically since the 2010s. Italy, Switzerland, eastern USA, Argentina, and Peru are fossil localities of named and well-preserved squalodelphinid fossils. Squalodelphinids are also known from New Zealand, Germany and Venezuela. However, only two specimens of this family have been reported from the North Pacific, in Washington State, USA, and Japan. Here, a new fossil dolphin (including the skull, right and left periotics and bullae, malleus, incus, hyoid bones and ribs) from the Haze Formation, Ichishi Group, Early Miocene (18.7–18.5 Ma) of Mie Prefecture, Japan is named as the new genus and species Miodelphinus miensis. Phylogenetic analysis places Miodelphinus miensis among squalodelphinids. The periotic of Miodelphinus miensis shows a large, posteriorly widened, ventrally opening, funnel-like articular depression between the posterior and articular processes of the periotic. Miodelphinus miensis contributes to expanding our knowledge of squalodelphinid diversity. Squalodelphinids were distributed widely not only in the Atlantic but also the South and North Pacific by the Early Miocene. This suggests that the family had a chronologically deeper origin such as the beginning of the Early Miocene or older.  

Keywords: Cetacea, Odontoceti, Burdigalian, epitympanic hiatus, Squalodelphinidae, new genus and species

  Miodelphinus miensis

 

Yoshihiro Tanaka and Ryohei Nakagawa. 2024. A New platanistoid (Odontoceti: Squalodelphinidae) from the Early Miocene of Japan. Journal of Systematic Palaeontology. 22(1); 2378783. DOI: doi.org/10.1080/14772019.2024.2378783  

  www.bunka.pref.mie.lg.jp/MieMu/m0062500408.htm

  www.city.sapporo.jp/museum/curator/documents/gakugeiinirukakenkyuteisei.pdf

[PaleoMammalogy • 2024] Fucaia humilis • The Oldest mysticete (Mysticeti: Aetiocetidae) in the Northern Hemisphere

Fucaia humilis 

 Tsai, Goedert & Boessenecker, 2024

DOI: 10.1016/j.cub.2024.03.011 

 twitter.com/TSAI_NTU508

Highlights: 

• A new fossil mysticete is described from Washington State, USA

• This fossil represents the oldest known mysticete from the Northern Hemisphere

• The small body size contrasts with larger coeval whales in the Southern Hemisphere

• The coastal kelp ecosystem likely fostered the diversification of early whales

Summary

Extant baleen whales (Mysticeti) uniquely use keratinous baleen for filter-feeding and lack dentition, but the fossil record clearly shows that “toothed” baleen whales first appeared in the Late Eocene.1 Globally, only two Eocene mysticetes have been found, and both are from the Southern Hemisphere: Mystacodon selenensis from Peru, 36.4 mega-annum (Ma) ago and Llanocetus denticrenatus from Antarctica, 34.2 Ma ago. Based on a partial skull from the lower part of the Lincoln Creek Formation in Washington State, USA, we describe the Northern Hemisphere’s geochronologically earliest mysticete, Fucaia humilis sp. nov. Geology, biostratigraphy, and magnetostratigraphy places Fucaia humilis sp. nov. in the latest Eocene (ca. 34.5 Ma ago, near the Eocene/Oligocene transition at 33.9 Ma ago), approximately coeval with the oldest record of fossil kelps, also in the northeastern Pacific.5 This observation leads to our hypothesis that the origin and development of a relatively stable, nutrient-rich kelp ecosystem5,6 in the latest Eocene may have fostered the radiation of small-sized toothed mysticetes (Family Aetiocetidae) in the North Pacific basin, a stark contrast to the larger Llanocetidae (whether Mystacodon belongs to llanocetids or another independent clade remains unresolved) with the latest Eocene onset of the Antarctic Circumpolar Current in the Southern Hemisphere.7,8,9 Our discovery suggests that disparate mechanisms and ecological scenarios may have nurtured contrasting early mysticete evolutionary histories in the Northern and Southern hemispheres.

Systematics

Cetacea

Mysticeti

Aetiocetidae

Fucaia humilis sp. nov.

Diagnosis: Fucaia humilis sp. nov. shares with other species of Fucaia a newly identified synapomorphy: a shallow and rounded secondary squamosal fossa on the posterolateral margin of the squamosal (Figure 1). Eomysticetids possess a similar character, but the homology within Mysticeti remains uncertain. Furthermore, Fucaia humilis sp. nov. differs from all other aetiocetids and other Fucaia species by having the following unique character combination: a shorter intertemporal constriction exposed on the skull vertex; the presence of a distinct nuchal tubercle at the junction of parieto-squamosal suture and supraoccipital; a broadly rounded, dorsally low, and lobate coronoid process of the mandible; the presence of a postcoronoid elevation; and rounded anterior border of the tympanic bulla.

 Etymology: In Latin, humilis refers to humble in English, alluding to the previously unknown humble early mysticete evolution in the Northern Hemisphere.

Cheng-Hsiu Tsai, James L. Goedert and Robert W. Boessenecker. 2024. The Oldest mysticete in the Northern Hemisphere. DOI: 10.1016/j.cub.2024.03.011

  twitter.com/TSAI_NTU508/status/1773657177531486386 

[Mammalogy • 2024] Orcinus rectipinnus & O. ater • Revised Taxonomy of eastern North Pacific Killer Whales (Orcinus orca): Bigg’s and Resident Ecotypes deserve Species Status

 

 Bigg’s killer whale Orcinus rectipinnus (Cope in Scammon, 1869)
Resident killer whale Orcinus ater (Cope in Scammon, 1869)

in Morin, McCarthy Fung, Durban, Parsons, Perrin, Taylor, Jefferson & Archer, 2024.

DOI: 10.1098/rsos.231368 

twitter.com/EmmaLuck22

Abstract

Killer whales (Orcinus orca) are currently recognized as a single ecologically and morphologically diverse, globally distributed species. Multiple morphotypes or ecotypes have been described, often associated with feeding specialization, and several studies have suggested taxonomic revision to include multiple subspecies or species in the genus. We review the ecological, morphological and genetic data for the well-studied ‘resident’ and Bigg’s (aka ‘transient’) ecotypes in the eastern North Pacific and use quantitative taxonomic guidelines and standards to determine whether the taxonomic status of these killer whale ecotypes should be revised. Our review and new analyses indicate that species-level status is justified in both cases, and we conclude that eastern North Pacific Bigg’s killer whales should be recognized as Orcinus rectipinnus (Cope in Scammon, 1869) and resident killer whales should be recognized as Orcinus ater (Cope in Scammon, 1869).

Keywords: Cetacea, odontocete, speciation

 

  Vertical images of (a) an adult male Bigg’s killer whale (BKW) from the West Coast Transient population of Bigg’s killer whales and (b) an adult male resident killer whale (RKW) from the sympatric Southern Resident population of resident killer whales.
Images are scaled to the estimated asymptotic lengths of 7.3 m and 6.9 m, respectively. Vertical images were collected using an octocopter drone using methods described by Durban et al. [2022], provided by John Durban and Holly Fearnbach.

Order Artiodactyla Montgelard, Catzefils and Douzery, 1997

 Cetacea Brisson, 1762

   Odontoceti Flower, 1867

     Superfamily Delphinoidea Flower, 1865

       Family Delphinidae Gray, 1821

Orcinus rectipinnus (Cope in Scammon, 1869)

Etymology: In Latin, recti means right or upright, and pinna means fin, feather or wing, most likely referring to the tall, erect dorsal fin of males.

Synonymy: Orca rectipinna Cope in Scammon, 1869: 22; original designation.

Common name: We propose continued use of the common name, ‘Bigg’s killer whale’, for this species, to honour Dr. Michael A. Bigg (1939–1990), who pioneered the study of North Pacific killer whales in the 1970s. This ecotype was formerly known as the ‘transient killer whale’.

Orcinus ater (Cope in Scammon, 1869)

Etymology: In Latin, ater means black or dark, which probably refers to the largely black colour of this species.

Synonymy: Orca ater Cope in Scammon, 1869: 22; original designation.

Common name: We are planning on engaging with North American Indigenous tribal groups and expect to eventually have a consensus common name, but in the meantime, we suggest continued use of ‘resident killer whale’ so as to maintain consistency.

 

Phillip A. Morin, Morgan L. McCarthy Charissa W. Fung, John W. Durban, Kim M. Parsons, William F. Perrin, Barbara L. Taylor, Thomas A. Jefferson and Frederick I. Archer. 2024. Revised Taxonomy of eastern North Pacific Killer Whales (Orcinus orca): Bigg’s and Resident Ecotypes deserve Species Status. R. Soc. Open Sci. 11: 231368. DOI: 10.1098/rsos.231368

 twitter.com/EmmaLuck22/status/1772915048337347033

[PaleoMammalogy • 2024] Aureia rerehua • A New platanistoid Dolphin (Cetacea: Odontoceti) from the Oligocene of New Zealand with a unique feeding method

 

Aureia rerehua

Meekin, Fordyce & Coste, 2024

DOI: 10.1080/03036758.2024.2314505

  Researchgate.net/publication/378366471

 

ABSTRACT

Pre-Miocene, stem odontocetes are known for their procumbent incisors and their function has been the subject of much speculation. Notable among these were Waipatia and several related taxa from New Zealand. Though some studies hypothesise the function of these teeth was for thrusting, the here described Aureia rerehua has unique teeth which might have formed a cage around small fish. These teeth, along with a weak vertex, flexible neck, and the smallest size among its relatives would make it a capable hunter in shallow waters. The addition of A. rerehua along with other taxa to phylogenetic analyses show three broad groups within taxa related to Waipatia and Otekaikea based on the divergence of the function of their teeth and the possible feeding strategies employed to catch prey.

KEYWORDS: Platanistoid, dental splay, waipatiid, Waipatiidae, Waitaki Valley

  

 A, The skull of Aureia rerehua in dorsal. B, Ventral, C, Left lateral view.
Note the splay of the teeth and facial topography.

Systematic palaeontology

Cetacea (Brisson, 1762)

Odontoceti (Flower, 1867)

Aureia rerehua gen. et sp. nov.

Etymology: The generic name derives from Māori aurei, ‘cloak pin’, referring to the shape of the teeth. The specific name, rerehua, means ‘beautiful’, referring to its well-preserved face.

Diagnosis: 

A. rerehua has features common in other stem odontocetes and some platanistoids; a subcircular fossa in the periotic fossa sensu de Muizon (1987), ventrally deflected anterior processes on the periotics, anterior spines on the tympanic bullae, distinct premaxillary clefts, and well developed antorbital notches (de Muizon, 1987; Geisler and Sanders, 2003; Geisler et al. 2011, 2012; Murakami et al. 2012a, 2012b; Tanaka and Fordyce 2014; Tanaka and Fordyce 2015b; Gaetán et al. 2018). A. rerehua is most like Otekaikea and Waipatia, with an attenuated rostrum, procumbent incisors, fossa for the articular rim of the periotic, and shallow fossae for the sternomastoid muscle (Moore, 1968; de Muizon, 1987; Tanaka and Fordyce, 2015b, 2014, 2017).

A. rerehua has unique basioccipital crests with posteroventral projections, a rectangular nuchal crest, flat ventral surfaces on the posterior process of the periotic, laterally splayed teeth, and a process on the subtemporal crest. Waipatiid-like odontocetes have developed vertices. The vertex of A. rerehua is less pronounced than W. maerewhenua or Otekaikea, shown in Figure 1C, possessing a flatter face like Papahu taitapu (Fordyce, 1994; Aguirre-Fernández and Fordyce, 2014; Tanaka and Fordyce 2014, 2015b). The posterior skull is straighter and steeper than that of other waipatiid-like odontocetes, making the lateral profile of the skull triangular.

  The teeth of Aureia rerehua.
 A series of the best-preserved teeth A are shown along with a section of in situ teeth preserved in the left mandible B.

Conclusion: 

OU22553 is the holotypes for a new species, A. rerehua, closely related to Otekaikea. It differs from other related odontocetes by its weak vertex, laterally splayed and recurved teeth, rectangular nuchal crest, and posterior flange on the basioccipital processes. Its widely splayed teeth are hypothesised to have clasped rather than strike fish. The unique dentition, small size, limited sense of smell, and dorsoventrally shallow skull illustrate a small dolphin foraging along shallow waters where speed and mobility are essential.

Shane Meekin, R. Ewan Fordyce and Amber Coste. 2024. Aureia rerehua, A New platanistoid Dolphin from the Oligocene of New Zealand with a unique feeding method. Journal of the Royal Society of New Zealand. DOI: 10.1080/03036758.2024.2314505

[Special issue: Fossil vertebrates from southern Zealandia]

  Researchgate.net/publication/378366471_Aureia_rerehua_a_new_platanistoid_dolphin_from_the_Oligocene_of_New_Zealand