Friday, April 30, 2021

[Ichthyology • 2021] A Revision of the Gobiid fish Genus Pseudogobius (Gobiidae, Tridentigerinae), with Description of Seven New Species from Australia and South-east Asia

Pseudogobius eos
 Larson & Hammer, 2021


The tridentigerine genus Pseudogobius is widespread, from temperate to tropical areas of the Indo-west Pacific. A morphological review of the genus was carried out, with the initial focus on South-east Asian and Australian species. There are about 21 nominal species in the genus; however, the type specimens for some nominal species are missing. Our work recognises 15 valid species so far, including seven new species, which are described herein: Pseudogobius aquilonius n. sp., P. cinctus n. sp., P. eos n. sp., P. hoesei n. sp., P. jeffi n. sp., P. rhizophora n. sp. and P. verticalis n. sp. We also conclude that P. poicilosoma (Bleeker, 1849) is the senior synonym of P. javanicus (Bleeker, 1856). Pseudogobius poicilosoma, P. gastrospilos (Bleeker, 1853) and P. javanicus are accepted here as conspecific, although the types are in poor condition (note that all three names were given to specimens collected within close proximity to each other in coastal Java, Indonesia). A key to valid species is presented. The revision benefited from an adaptive feedback loop with companion genetic analyses, with the most comprehensive data available for the Australian region. Broader preliminary genetic data suggest the potential for recognition of additional cryptic species, with the current study providing a platform for future systematic work. Pseudogobius are a prominent part of estuarine biodiversity in the Indo-west Pacific, and this study helps to highlight the need to better understand the taxonomy and conservation requirements of cryptobenthic fishes.

Keywords: Pisces, Indo-west Pacific, morphology, estuarine, biodiversity

 Helen K. Larson and Michael P. Hammer. 2021. A Revision of the Gobiid fish Genus Pseudogobius (Teleostei, Gobiidae, Tridentigerinae), with Description of Seven New Species from Australia and South-east Asia. Zootaxa. 4961(1); 1-85. DOI: 10.11646/zootaxa.4961.1.1

Meet the gobies
A new paper clarifies the taxonomic status of the snubnose gobies, including seven newly-described species.

[Cnidaria • 2020] Plumularia roxanae • A New Epiphytic Hydroid (Hydrozoa: Plumulariidae) from the Indo-Pacific

Plumularia roxanae
Galea, 2020

A new epiphytic, small-sized species of Plumularia Lamarck, 1816, P. roxanae sp. nov., is described based on fertile material from Bali, Indonesia. Its deep hydrothecae are characteristically narrowed distally through a distinctive hypertrophy of the free portion of their adaxial wall. Its minute gonothecae, however, are comparable in shape and size to those of the well-known, circumtropical P. floridana Nutting, 1900.

Plumularia roxanae sp. nov.
(A) Portion of cormoid. (B) Detail of a portion of stem with proximal parts of four successive cladia. (C) Detail of a stem internode, showing centrally an apophysis and the proximal part of the corresponding cladium. (D) Proximal most hydrotheca. (E) Distalmost hydrotheca, note the absence of the distal part of its corresponding internode. (F) Portion of fertile stem with rows of gonothecae. (G) Gonotheca. (H) More detailed view of a gonotheca, showing apical aperture (arrowhead).
 Scale bars: 50 µm (H), 100 µm (C-E, G), 200 µm (B, F), 500 µm (A).

Plumularia roxanae sp. nov.  
Diagnosis: Small-sized, epiphytic Plumularia arising from stolon with perisarcal spurs, giving rise to monosiphonic stems divided homomerously by transverse nodes into rather short, collinear internodes, each with a subterminal cladial apophysis provided with an inconspicuous adaxial mamelon and a pair of axillar nematothecae; cladia heteromerously segmented by alternating straight and oblique nodes into short, ahydrothecate internodes occasionally provided with a nematotheca, and up to three, comparatively longer hydrothecate internodes accommodating a centrally-placed hydrotheca and its three associated nematothecae; hydrotheca deep, saccate, partly adnate, distal portion distinctly constricted through the hypertrophy of the free adaxial wall that adopts a triangular shape, considerably reducing the thecal lumen; abaxial wall slightly convex; gonothecae in two closely-set, parallel rows along the stem, borne on the cladial apophyses, minute, ovoid, thick-walled.

 Etymology: It is my great pleasure to dedicate this new species to the memory of my late mother, Roxana S. Galea (née Florescu, 5 Oct. 1946 – 18 Jan. 1994), a Romanian biologist, who passed on to me her interest for natural sciences.

Horia R. Galea. 2020. Plumularia roxanae, A New Epiphytic Hydroid (Cnidaria: Hydrozoa: Plumulariidae) from the Indo-Pacific. Revue suisse de Zoologie. 127(2); 367-376. DOI:  10.35929/RSZ.0026 

[Ichthyology • 2021] Chondrostoma smyrnae • A New Nase (Cypriniformes, Leuciscidae) from the Tahtalı Reservoir Drainage in the Aegean Sea Basin

Chondrostoma smyrnae
Küçük, Çiftçi, Güçlü & Turan, 2021

Chondrostoma smyrnae, a new species, from the Tahtalı reservoir drainage is distinguished by having a slightly arched lower jaw with a well-developed keratinised edge, a deep and cylindric body, a complete lateral line with 47–52+1 total scales, 8–9 scale rows between the lateral line and the dorsal-fin origin, 4 scale rows between the lateral line and the pelvic fin-origin, and 19–23 gill rakers on the first gill arch. Moreover, molecular analyses using full cyt b (1141 bp) and partial coI (652 bp) sequences of the mitochondrial genome from specimens of the new species, C. smyrnae and specimens belonging to other Chondrostoma species from central and western Anatolia demonstrated that the C. smyrnae is easily differentiated by their high pairwise genetic distances of cyt b and coI data set (>2.20 and 1.03%, respectively) and by their position in the phylogenetic trees obtained through Maximum Likelihood (ML) methodology.

Key Words: Cytochrome b, Cytochrome oxidase I, freshwater fish, taxonomy, Western Anatolia

Figure 3. a. Chondrostoma smyrnae, IFC-ESUF 03–1567, just after fixation form, 167 mm SL, Turkey: Tahtalı reservoir; b. IFC-ESUF 03–1566, holotype, 191 mm SL, Turkey: Tahtalı reservoir; c. IFC-ESUF 03–1567, paratype 205 mm SL, Turkey: Tahtalı reservoir;
d. Chondrostoma turnai, IFC-ESUF 03–1557, 197 mm SL, Turkey: Çine stream.

Chondrostoma smyrnae sp. nov.

Diagnosis: Chondrostoma smyrnae is distinguished from other species occur to adjacent basin by a cylindrical body (body width at dorsal-fin origin 16.8–19.3% SL, vs. 13.3–15.4 in C. turnai (Fig. 3d), 14.1–16.6 in C. meandrense, 12.0–16.3 in C. holmwoodii, 12.4–15.7 in C. fahirae, except C. beysehirense), a wider head (head width at anterior margin of eye 55–65% HL, vs. 42–54), by having less lateral line scales (48–53 vs. 60–67 in C. beysehirense, 60–66 in C. holmwoodii and 56–60 in meandrense, except C. turnai and C. fahirae). Chondrostoma smyrnae is further distinguished from C. turnai by the absence keel between pelvic fin-origin and anus (vs. present in specimens larger than 160 mm SL), a straight or slightly arched lower jaw (vs. arched), more total lateral line scales (48–53, vs. 44–51), and fewer gill rakers on first gill arch (19–23, vs. 22–27). Also, C. smyrnae further differs from C. turnai by the shape of jaws, hyomandibular, quadrate and the fifth brachial gill arc. In C. smyrnae, the dentary thick and coronoid process inclined forward (vs. thin and coronoid process nearly vertical); premaxilla very deep and posterior edge short (vs. slender and posterior edge long); hyomandibular long and narrow (vs. short and wide), the fifth brachial gill arc wide angle (vs. narrow angle) and pharyngeal teeth wide (vs. thin); outer margin of quadrate slightly pointed (vs. rounded) (Figs 4, 5).

Etymology: The species is named for Smyrna, the historic name of the city known today as Izmir. A noun in genitive, indeclinable.

 Fahrettin Küçük, Yılmaz Çiftçi, Salim Serkan Güçlü and Davut Turan. 2021. Chondrostoma smyrnae, A New Nase from the Tahtalı Reservoir Drainage in the Aegean Sea Basin (Teleostei, Leuciscidae). Zoosystematics and Evolution. 97(1): 235-248. DOI: 10.3897/zse.97.63691

[Botany • 2021] Anthyllis apennina (Fabaceae: Papilionoideae) • A New Species from central Apennine (Italy)

Anthyllis apennina F.Conti & Bartolucci

in Conti & Bartolucci, 2021.

A new species of Anthyllis endemic to central Apennine growing in dry pastures on limestone in the montane belt, within Abruzzo and Lazio administrative regions (central Italy), is here described and illustrated and the IUCN assessment is proposed. This new species belongs to the morphologically very variable Anthyllis vulneraria species complex and it is close to A. pulchella (south-eastern Europe and Caucasus), but it can be clearly distinguished by its smaller flowers, mainly light yellow-coloured, bracts longer than flowers, calyx pink-coloured (usually only at apex) and size of cauline leaves and leaflets. Furthermore, the name A. pulchella is here lectotypified, by a second-step typification, on a specimen preserved at PAD.

Keywords: Abruzzo, Anthyllis vulneraria species complex, Italian endemics, Lazio, Loteae, Papilionoideae, taxonomy

Figure 3. Holotype of Anthyllis apennina F.Conti & Bartolucci
 (APP No. 59652, reproduced with permission of the Herbarium, Centro Ricerche Floristiche dell’Appennino, Italy).

Figure 2. Anthyllis apennina F.Conti & Bartolucci, sp. nov.
 A inflorescence (Mt. Tricella, photo F. Conti) B bracts of inflorescences (Mt. Tricella, photo F. Conti) C geminate inflorescences (Prati del Sirente, photo F. Conti) D drawing from herbarium specimen APP No. 59887 collected on Colle Biferno a calyx and pod with stylus and stigma b standard c wing d keel. 

Anthyllis apennina F.Conti & Bartolucci, sp. nov.
Diagnosis: Anthyllis apennina differs from A. pulchella by the bigger cauline leaves and leaflets, leaves evenly distributed along the flowering stem vs. concentrated in lower half, higher number of inflorescences 2–5(–10) vs. 1–2, smaller flowers with standard (7.9–)8.5–9.9(–10.3) vs. (10–)10.4–13.6(–13.8) mm long, longer bracts (12–)14–23(–26) vs. (5.8–)6.5–11(–12) mm long, longer than flowers, with longer lobes (10–)11–21.5(–24) vs. (3.2–)3.9–7.5(–9) mm long, narrowly triangular and acute to apiculate vs. more or less parallel-sided and obtuse and by the colour of flowers which are mainly light yellow or flushed with pink vs. purplish-pink or cream flushed with pink and the calyx which is mainly pink only in the upper part.

Etymology: Anthyllis apennina is named after the Apennine to which the species is endemic.

Habitat: Pastures in montane belt from 1200 to 1800 m a.s.l.

Distribution: Central Apennine in Lazio and Abruzzo (Fig. 1).

 Fabio Conti and Fabrizio Bartolucci. 2021. Anthyllis apennina (Fabaceae), A New Species from central Apennine (Italy). PhytoKeys. 176: 111-129. DOI: 10.3897/phytokeys.176.62774

[Herpetology • 2021] Dixonius somchanhae • A New Species of Dixonius (Squamata: Gekkonidae) from Vientiane Capital, Laos

Dixonius somchanhae  
 Nguyen, Luu, Sitthivong, Ngo, Nguyen, Le & Ziegler, 2021

A new species of the gekkonid genus Dixonius is described from Huaysorn-Huaysua village, Nasaithong District, Vientiane Capital, Laos. The new species can be distinguished from all other species by a combination of the following characters: maximum SVL 47.1 mm; 19–21 longitudinal rows of dorsal tubercles at midbody; 23–26 longitudinal rows of ventrals across the abdomen; 7 or 8 supralabials, 6 in mid-orbital position; 5 or 6 infralabials; 5 or 6 precloacal pores in males, femoral pores lacking; precloacal and femoral pores absent in females; a canthal stripe running from rostrum through the eye and terminating at back of head; dorsum brown with irregular dark marks. In phylogenetic analyses, the species is recovered as the sister taxon to D. siamensis, which occurs in Laos, Thailand, and Vietnam. Genetically, the two species are approximately 9.4% divergent from each other based on the complete mitochondrial ND2 gene with six partial or complete adjacent tRNAs. It is the 12th species known in the genus Dixonius and the second Dixonius species described from Laos.
Keywords: Reptilia, Dixonius somchanhae sp. nov., morphology, molecular phylogeny, taxonomy

Dixonius somchanhae sp. nov.

Thuong Huyen Nguyen, Vinh Quang Luu, Saly Sitthivong, Hanh Thi Ngo, Truong Quang Nguyen, Minh Duc Le and Thomas Ziegler. 2021. A New Species of Dixonius (Squamata: Gekkonidae) from Vientiane Capital, Laos. Zootaxa. 4965(2); 351–362. DOI: 10.11646/zootaxa.4965.2.8

[Paleontology • 2021] Voay robustus • Paleogenomics Illuminates the Evolutionary History of the Extinct Holocene “horned” Crocodile of Madagascar

Voay robustus (Grandidier & Vaillant, 1872)

in Hekkala, Gatesy, Narechania, ... et Amato, 2021. 
Paintings of crocodylians are by C. Buell, 
photo of Voay (AMNH FR-3101) is by E. Hekkala.

Ancient DNA is transforming our ability to reconstruct historical patterns and mechanisms shaping modern diversity and distributions. In particular, molecular data from extinct Holocene island faunas have revealed surprising biogeographic scenarios. Here, we recovered partial mitochondrial (mt) genomes for 1300–1400 year old specimens (n = 2) of the extinct “horned” crocodile, Voay robustus, collected from Holocene deposits in southwestern Madagascar. Phylogenetic analyses of partial mt genomes and tip-dated timetrees based on molecular, fossil, and stratigraphic data favor a sister group relationship between Voay and Crocodylus (true crocodiles). These well supported trees conflict with recent morphological systematic work that has consistently placed Voay within Osteolaeminae (dwarf crocodiles and kin) and provide evidence for likely homoplasy in crocodylian cranial anatomy and snout shape. The close relationship between Voay and Crocodylus lends additional context for understanding the biogeographic origins of these genera and refines competing hypotheses for the recent extinction of Voay from Madagascar.

Voay robustus (Grandidier & Vaillant, 1872)
A skull of Voay robustus collected at Ampoza (44° 42.3’ E, 22° 18.9’ S, 570 m elevation) during the joint Mission Franco-Anglo-American expedition from 1927–1930 (White, 1930).

Phylogenetic relationships of Voay robustus based on partial mitochondrial (mt) genomes support a sister group relationship between Voay and a monophyletic Crocodylus (true crocodiles).
 The tree shown is based on ML analysis (partitioned by gene) and includes data from all four builds of the Voay mt genome. Bootstrap scores at each node are (from top to bottom): all four builds of Voay mt genome with partitioned ML analysis, Voay AMNH FR-3101 C. porosus reference build with partitioned ML analysis, Voay AMNH FR-3101 Osteolaemus reference build with partitioned ML analysis, Voay AMNH FR-3103 C. porosus reference build with partitioned ML analysis, Voay AMNH FR-3103 Osteolaemus reference build with partitioned ML analysis, and all four builds of Voay mt genome with equally-weighted parsimony analysis. Bootstrap scores for the two internodes that bound the branching point of Voay are highlighted in red. All trees were rooted with bird, turtle, and lizard outgroups (not shown). Higher level taxa are delimited by brackets to the right of species names. Paintings of crocodylians are by C. Buell, and photo of Voay (AMNH FR-3101) is by E. Hekkala.


Tip-dated Bayesian timetree showing the phylogenetic relationships of Voay robustus relative to extant and extinct crocodylids with a mapping of geographic distributions (colored squares at tips of branches).
Bayesian posterior probabilities are at nodes; support scores for the two internodes that bound the branching point of Voay are highlighted (red). Optimization of geographic regions to internal nodes (colored circles) is based on equally-weighted parsimony and implies an African ancestry for the overall clade with minimally two migrations to Australia/Asia, two to the New World, and two to Madagascar. An identical mapping of ancestral areas results for minimum area change (MAC) parsimony analysis. The Voay AMNH FR-3101 C. porosus mt genome build (partitioned by 1st, 2nd, 3rd codons) was employed in combination with morphological characters and stratigraphic data from Lee and Yates (2018). Taxa that are distantly related to Voay are pruned from the figure; for the complete timetree, see Supplementary Data 2. Paintings of crocodylians are by C. Buell; photo of Voay (AMNH FR-3101) is by E. Hekkala.

E. Hekkala, J. Gatesy, A. Narechania, R. Meredith, M. Russello, M. L. Aardema, E. Jensen, S. Montanari, C. Brochu, M. Norell and G. Amato. 2021. Paleogenomics Illuminates the Evolutionary History of the Extinct Holocene “horned” Crocodile of Madagascar, Voay robustus. Communications Biology. 4: 505. DOI: 10.1038/s42003-021-02017-0

Extinct 'horned' crocodile gets new spot in the tree of life
New ancient DNA-based study on Madagascar crocodile suggests that modern crocodiles likely originated in Africa

[Botany • 2021] Begonia rigidifolia ssp. sonhungii (Begoniaceae, sect. Platycentrum) • A New Subspecies from Limestone Hills in Central Vietnam

Begonia rigidifolia Aver. ssp. sonhungii C.W.Lin

in Lin, Phan & Nguyen, 2021. 

Begonia rigidifolia Aver. ssp. sonhungii C.W.Lin (sect. Petermannia, Begoniaceae) from Central Vietnam is hereby described and illustrated as new. It resembles B. rigidifolia ssp. rigidifolia, but differs in its very sparsely puberulous (vs. glabrous), darker toned lamina that is embellished with a pale green broad band (vs. emerald green lamina with irregular radiantly arranged dark spots), stamens widely obovate (vs. obovate) and capsule with wider abaxial wing 6–10 mm (vs. 2–3 mm).

Keywords: biodiversity, endemic, karst region, taxonomy, Eudicots

Begonia rigidifolia Aver. ssp. sonhungii C.W.Lin 

Che-Wei Lin, Luong Cong Son Phan and Ngoc Hung Nguyen. 2021. Begonia rigidifolia ssp. sonhungii (sect. Petermannia, Begoniaceae), A New Subspecies from Limestone Hills in Central Vietnam. Phytotaxa. 498(2); 139–144. DOI: 10.11646/phytotaxa.498.2.7

[Botany • 2021] Utricularia lihengiae (Lentibulariaceae) • A New Species from Northwest Yunnan, China

Utricularia lihengiae C. L. Long & Z. Cheng 

in Cheng, Fang, Wang & Long, 2021. 
李恒挖耳草  ||  DOI: 10.3897/phytokeys.177.63346

Utricularia lihengiae, a new species from the Dulongjiang region of northwest Yunnan, China, is here described and illustrated. The new species belongs to the section Oligocista and is similar to U. bifida L. and U. scandens Benj., from which it can be easily distinguished by the dark purple stripe on the corolla. The new species also differs in its shorter inflorescence and the shape of the calyx lobes.

Keywords: Bladderwort, insectivorous plant, taxonomy, Yunnan Province

 Utricularia lihengiae C. L. Long & Z. Cheng 
A habitat B whole plant C traps and laminar leaves D leaf E calyx upper lobe F calyx lower lobe G bracts H–J frontal, dorsal and lateral view of the flower
 (A–J Photos by Z. Cheng.).

Utricularia lihengiae C. L. Long & Z. Cheng, sp. nov.  
“李恒挖耳草” (Li Heng Wa Er Cao)  

Diagnosis: U. lihengiae is similar to U. bifida L. (1753: 18), but differs by the inflorescences 2–4 cm long (vs. mostly 10–20 cm long in U. bifida), calyx upper and lower with apex acuminate (vs. calyx upper lobe, apex obtuse, calyx lower lobe, apex rounded or very shortly bifid in U. bifida), 3–5 dark purple stripes on the upper corolla lip, 3 dark purple stripes on lower corolla lip (vs. absent in the upper and lower corolla lip in U. bifida); U. lihengiae is similar to U. scandens Benj. (1847: 309), but differs by the smaller inflorescence 2–4 cm long (vs. mostly 15–35 cm long in U. scandens), peduncle of U. lihengiae is erect (vs. peduncle usually twining in U. scandens), calyx lower lobe with apex acuminate (vs. calyx lower lobe with apex rounded or very shortly bifid in U. scandens), upper calyx lobe of U. lihengiae is shorter than upper corolla lip (vs. upper calyx lobe longer than upper corolla lip in U. scandens), 3–5 dark purple stripes on the upper corolla lip, 3 dark purple stripes on lower corolla lip (vs. absent in the upper and lower corolla lip in U. scandens).

Distribution and habitat: The only known locality of this taxon is in Dulongjiang Township, Gongshan Dulong and Nu Autonomous County, Northwest Yunnan, China. The site is located in an open area in a primeval forest dominated by Fagaceae, Magnoliaceae and Ericaceae. The observed population is very small, with fewer than 80 plants growing in the moss amongst damp grass on the roadside, accompanied by the moss Polytrichum commune Hedwig (1801: 88), as well as Vaccinium chaetothrix Sleumer (1941: 432), and Acorus tatarinowii Schott (1859: 101). The elevation is 2800–2900 metres above sea level. The climate here is rainy and humid, with rain falling for most of the year.
Etymology: Named in honor of Prof. Li Heng, a Chinese botanist who has made significant contributions to the knowledge of the flora of Dulongjiang region.

 Zhuo Cheng, Qiong Fang, Fei Wang and Chun-Lin Long. 2021. Utricularia lihengiae (Lentibulariaceae), A New Species from Northwest Yunnan, China. PhytoKeys. 177: 17-24. DOI: 10.3897/phytokeys.177.63346

Wednesday, April 28, 2021

[Ichthyology • 2021] Etelis boweni • A New Cryptic Deepwater Eteline Snapper (Perciformes: Lutjanidae) from the Indo‐Pacific


Etelis boweni 
 Andrews, Fernandez‐Silva, Randall & Ho, 2021

 Photo: NOAA Fisheries

A new species of Etelis is described based on 16 specimens collected from the Red Sea and Western Australia, with confirmed genetic records throughout the Indo‐West Pacific. It is similar to and was often misidentified as Etelis carbunculus Cuvier, with both species sharing the diagnostic character of low number of developed gill rakers. Nonetheless, the two species are genetically divergent and differ morphologically in adult body length; proportions of eye, snout, cheek and caudal fin; shape of head, opercular spine and sagittal otolith; and coloration of the tip of the upper caudal fin. Etelis boweni has a wide Indo‐west Pacific distribution that largely overlaps with E. carbunculus, and the two species are often caught on the same fishing line.

Keywords: Actinopterygii, cryptic species, ichthyology, Pisces, snappers, taxonomy


Etelis boweni sp. nov.
Bowen's Red Snapper, Giant Ruby Snapper

Etymology: The authors are grateful to name this fish after Dr. Brian W. Bowen of the Hawaiʻi Institute of Marine Biology, University of Hawaiʻi, in recognition of his contributions to the field of Ichthyology, and in particular for his use of molecular genetic techniques in support of the taxonomy of fishes.

A fresh caught specimen of Etelis boweni sp. nov. from East Bank, American Sāmoa in 2016, weight 31 kg, estimated >1 m total length.
Photo: NOAA Fisheries

Kimberly R. Andrews, Iria Fernandez‐Silva, John E. Randall and Hsuan‐Ching Ho. 2021. Etelis boweni sp. nov., A New Cryptic Deepwater Eteline Snapper from the Indo‐Pacific (Perciformes: Lutjanidae). Journal of Fish Biology. DOI: 10.1111/jfb.14720  

[Paleontology • 2021] Yamatosaurus izanagii • A New Basal Hadrosaurid (Dinosauria: Ornithischia) from the latest Cretaceous Kita-ama Formation in Japan implies the Origin of Hadrosaurids

(Silhouette & left) Yamatosaurus izanagii 
Kamuysaurus japonicus (right)

 Kobayashi, Takasaki, Kubota & Fiorillo, 2021
Life reconstruction by Masato Hattori 

Here we describe a partial hadrosaurid skeleton from the marine Maastrichtian Kita-ama Formation in Japan as a new taxon, Yamatosaurus izanagii gen. et sp. nov., based on unique characters in the dentition. Our phylogenetic analysis demonstrates Yamatosaurus izanagii belongs to Hadrosauridae, composed of Hadrosaurus foulkii + (Yamatosaurus izanagii + (Saurolophinae + Lambeosaurinae)). The coracoid lacks a biceps tubercle as in non-hadrosaurid hadrosauroids, suggesting its presence is a key feature for the clade of Saurolophinae and Lambeosaurinae. The evolutionary rates analysis further supports that shoulder and forelimb features, which are likely to have been involved in locomotion, were important for the early evolution of Hadrosauridae. Our biogeographic analyses show that basal hadrosaurids were widely distributed in Asia and Appalachia, that the clade of Saurolophinae and Lambeosaurinae originated in Asia, and that eastern Asia may have served as a refugium of relict hadrosauroid taxa such as Plesiohadros djadokhtaensis, Tanius sinensis, and Yamatosaurus izanagii during the Late Cretaceous. The contemporaneous occurrence of basal (Yamatosaurus izanagii) and derived (Kamuysaurus japonicus) hadrosaurids during the Maastrichtian in Japan is the first record in Asia. Because of the long geographical distance between these localities, they likely did not co-exist, but instead demonstrate some level of provinciality.


Map of Japan, showing the localities of Yamatosaurus izanagii gen. et sp. nov. on Awaji Island (green star), Kamuysaurus japonicus in Mukawa Town (blue star), and other Late Cretaceous hadrosauroids (red circles) (a) and the location of Locality Aw on Awaji Island (b).
Ammonite biostratigraphy, showing the position of the Nostoceras hetonaiense Zone (c).
Stratigraphic sections of the Kita-ama and Hakobuchi formations (d) and depositional environments of Yamatosaurus izanagii (green star) and Kamuysaurus japonicus (blue star) (e).
Note that (d) differs from Fig. 1 of Tanaka et al.27 because we corrected errors, including the scale and the stratigraphic boundaries between the Kita-ama and Noda formations and between the Campanian and Maastrichtian.

Silhouette of Yamatosaurus izanagii, showing recovered skeletal elements (f) (Courtesy of Genya Masukawa).
Life reconstruction of Yamatosaurus izanagii (left) and Kamuysaurus japonicus (right) (g) (Courtesy of Masato Hattori).
(a) and (b) were created by K. Kubota, by using Adobe Illustrator 2021 (

Right dentary of Yamatosaurus izanagii gen. et sp. nov. in lateral (a), medial (b), dorsal (c), ventral (d), and anterior (e) views. Numbers in white in (b) indicate the positions of nutrient foramina.

An isolated dentary tooth of Yamatosaurus izanagii gen. et sp. nov. from left side in lingual (a) and mesial (b) views and its denticles (c). Isolated dentary teeth of Yamatosaurus izanagii gen. et sp. nov. from left side in distal (d,f) and occlusal (e,g) views. Dentary teeth of Yamatosaurus izanagii gen. et sp. nov. in place on the right dentary in lingual (h) and occlusal (i) view. Numbers in (h), (i), and (j) are tooth positions. Occlusal surfaces of the eleventh and fourteenth teeth are highlighted in light gray in (i). Scales for (a), (b), and (d) to (i) are 1 cm. Scales for (c) and (j) are 0.5 mm and 3 cm, respectively.

Systematic paleontology
Dinosauria Owen, 1842
Ornithischia Seeley, 1888

Ornithopoda Marsh, 1881
Hadrosauridae Cope, 1869

Yamatosaurus izanagii gen. et sp. nov.

 Holotype: MNHAH D1-033516, a right dentary, a right surangular, twelve isolated dentary teeth, four cervical vertebrae, a distal caudal vertebra, three cervical ribs, and a coracoid. This specimen is stored in the Museum of Nature and Human Activities, Hyogo, Sanda City, Hyogo Prefecture, Japan.

Diagnosis: A hadrosaurid with unique characters in having only a single tooth as a minimum number of functional teeth per tooth position in the middle of the dentary dental battery (9th, 11th, 14th, 16th, 19th, 21st, and 23rd tooth positions) and the complete absence of the “branched ridges” on the dentary tooth occlusal surfaces. It is also unique in the combination of the additional following characters: the low angle between the dentary symphysis and lateral surface of the dentary and ventrally facing ventral surface of the surangular.
Etymology: Yamato” refers to the ancient name for a region of the Japanese archipelago, including the western half of the main island (Honshu Island), Shikoku Island, and the northern half of Kyushu Island, ruled by the Yamato Kingdom from the third to the seventh century. “Sauros” means reptiles. The specific name, “izanagi”, refers to a deity in Japanese mythology, which created eight countries of Yamato with another deity, Izanami, based on the oldest history book in Japan called “Kojiki (Records of Ancient Matters)”, published in 712 CE (Common Era). The first country created was the Awaji Island, followed by the Shikoku, Oki, Kyushu, Iki, Tsushima, Sado, and Honshu islands.

Locality and horizon: Locality Aw (Morozumi) of Yura Town, Sumoto City of the Awaji Island, Hyogo Prefecture, Japan; the early Maastrichtian (71.94–71.69 Ma) Kita-ama Formation of the Izumi Group.

Yoshitsugu Kobayashi, Ryuji Takasaki, Katsuhiro Kubota and Anthony R. Fiorillo. 2021. A New Basal Hadrosaurid (Dinosauria: Ornithischia) from the latest Cretaceous Kita-ama Formation in Japan implies the Origin of Hadrosaurids. Scientific Reports. 11: 8547. DOI: 10.1038/s41598-021-87719-5

新属新種の恐竜「ヤマトサウルス・イザナギイ」 淡路島・洲本で発見の恐竜化石命名