[Paleontology • 2026] Chosha praecursor • Amphibious stem-insect sheds light on Colonization of Land

Chosha praecursor

Tihelka,  Vásquez, Engel, Schram, Lozano-Fernandez & Cai, 2026

DOI: doi.org/10.1038/s41586-026-10961-2

Abstract

Molecular clock analyses, trace fossils, exceptionally preserved amphibious stem-myriapods and sea scorpions have recently challenged classical assumptions about the timeline of the animal colonization of land, suggesting that terrestrial ecosystems may date back as far as the Cambrian period. However, the early evolutionary history of the most successful clade of animals, the insects, has remained elusive, as the period of their early diversification constrained by time divergence estimates falls within the notorious ‘hexapod gap’ in the fossil record. Here we describe Chosha praecursor gen. et sp. nov. from the Carboniferous period (Late Mississippian epoch, approximately 324 million years ago) Tesnus Formation in Texas. Cross-polarized light imaging reveals that C. praecursor possesses insect apomorphies including an ovipositor and a terminal filament but differs from crown-group insects, most notably with respect to the presence of multisegmented abdominal legs with paddle-like modifications. Our phylogenetic reconstruction recovers C. praecursor as a hexapod, strongly favouring its placement as an early-diverging insect. A revision of three other enigmatic hexapod fossils, the Devonian period Leverhulmia and two undescribed Carboniferous fossils from the Mazon Creek Lagerstätte, demonstrates diverse body organization in Palaeozoic wingless insects. Together, these stem-group fossils represent the earliest uncontested insects and partly reconcile the incongruence between molecular clock estimates and the fossil record. The unusual abdominal gill-like appendages of Chosha suggest a semiaquatic mode of life in at least some stem-insects and revise our understanding of the assembly of insect morphological organization.

Chosha praecursor gen. et sp. nov. 

Erik Tihelka, Carlos Vásquez, Michael S. Engel, Frederick R. Schram, Jesus Lozano-Fernandez and Chenyang Cai. 2026. Amphibious stem-insect sheds light on colonization of land. Nature. DOI: doi.org/10.1038/s41586-026-10961-2 [26 August 2026]

[Invertebrate • 2026] Polycapus rubrum, Stelletta plana, ... • Four New Demosponges from Alaska and the Designation of A New Genus in Hymedesmiidae (Heteroscleromorpha, Poecilosclerida)

 

Stelletta plana sp. nov.

Polycapus rubrum gen. nov. & sp. nov.

Lehnert, Rooney & Everett, 2026

 DOI: doi.org/10.11646/zootaxa.5857.2.6 

www.fisheries.NOAA.gov 

 

Abstract

An investigation of Alaska’s extraordinarily rich sponge fauna was conducted utilizing samples retained as bycatch during National Marine Fisheries Service stock assessment bottom trawl surveys in the Gulf of Alaska and Aleutian Islands between 1997 and 2021. Subsequent analysis of the samples revealed four new species, which are representatives of four different orders of demosponges: Cladocroce cylindrica sp. nov., Julavis borealis sp. nov., Polycapus rubrum gen. nov. & sp. nov., and Stelletta plana sp. nov.. The new species are described and compared to congeners. Polycapus rubrum was assigned to the Hymedesmiidae but the combination of acanthoxeas and chelae does not occur in any other existing genus within the family which necessitates a new genus. These new collections further highlight the richness of the sponge fauna from the region.

Porifera, new species, North Pacific, Aleutian Islands, Gulf of Alaska, Tetractinellida, Axinellida, Haplosclerida, Stelletta, Polycapus, Julavis, Cladocroce, 28S

Cladocroce cylindrica, is a stalked, branching sponge distinguished by a unique spicule framework that forms a complex, web-like network. 

Julavis borealis, grows like a thin mat over organisms. Its presence in Alaska represents a massive high-latitude geographic leap for a group previously found only in warm, tropical environments. 

Cladocroce cylindrica sp. nov.  

Julavis borealis sp. nov.  

Polycapus rubrum gen. nov. & sp. nov. 

Stelletta plana sp. nov.

Helmut LEHNERT, Sean C. ROONEY and Meredith V. EVERETT. 2026. Four New Demosponges from Alaska and the Designation of A New Genus in Hymedesmiidae (Heteroscleromorpha, Poecilosclerida).  Zootaxa. 5857(2); 317-334. DOI: doi.org/10.11646/zootaxa.5857.2.6 [2026-07-29]

Nine Species of Deep-Sea Sponges Discovered in Alaska

www.fisheries.NOAA.gov/feature-story/nine-species-deep-sea-sponges-discovered-alaska

[Paleontology • 2026] Mandrasuchus milleri • A New alligatorid (Crocodylia: Alligatoridae) from the Early Paleocene (Danian) of the Denver Basin supports earliest Paleocene North American alligatorid radiation

 

Mandrasuchus milleri

Lessner, Sherman, Petermann, Panigot, Duffy & Lyson, 2026 

 

DOI: doi.org/10.1080/02724634.2026.2712566 

Illustration by Andrey Atuchin

ABSTRACT

The North American eusuchian fossil record through the Cretaceous–Paleogene (K–Pg) mass extinction shows a remarkable increase in diversity across the K–Pg boundary through the early Eocene. This is in contrast to most other vertebrate clades. Despite the group’s uninterrupted existence across the K–Pg boundary, gaps remain in the alligatorid fossil record, particularly near the K–Pg boundary and geographically in Colorado. Here we describe a new alligatorid, Mandrasuchus milleri, gen. et sp. nov., from the lower Paleocene Denver Formation of Corral Bluffs, Colorado, represented by over 15 specimens. We identify a globidontan alligatorine by the globular caudal dentition and blunted rostrum. Regardless of precise taxonomic assignment, the alligatorid is stratigraphically the earliest confirmed alligatorine, with diagnostic crania from ∼350 kyrs (Puercan 2 North American Land Mammal Age [NALMA]) and referred globular teeth from ∼200 kyrs (Puercan 1 NALMA) post-K–Pg mass extinction. The alligatorine is a new representative of a largely unresolved portion of the crocodylian phylogeny, and its addition could help resolve relationships of early diverging alligatorids and taxa historically referred to Allognathosuchus. This taxon’s distinct rostral morphology and globidont dentition suggest its ability to engage in a macrogeneralist diet. Dietary niche partitioning is likely present in this ecosystem as M. milleri lived alongside the generalist macrocarnivore Borealosuchus sternbergii, the other known Denver Formation crocodylian. The eusuchian survivorship across the K–Pg mass extinction and the morphological diversity of these apex freshwater predators underscores the degree to which freshwater terrestrial ecosystems were buffered from Earth's last mass extinction.

Mandrasuchus milleri hunting crayfish along a river bank in Colorado some 65.5 million years ago.

 Mandrasuchus milleri, gen. et sp. nov.

Emily J. Lessner, Sadie M. Sherman, Holger Petermann, Eldon Panigot, Franklin Duffy and Tyler R. Lyson. 2026. New alligatorid, Mandrasuchus milleri, from the Early Paleocene (Danian) of the Denver Basin supports earliest Paleocene North American alligatorid radiation. Journal of Vertebrate Paleontology. e2712566. DOI: doi.org/10.1080/02724634.2026.2712566 [02 Sep 2026]

[Crustacea • 2026] Cambarus emegi • A New Stream-dwelling Species of Cambarus (Decapoda: Cambaridae) from Virginia and Pennsylvania (USA) with Notes on its Distribution, Ecology, and Conservation Status

 

Cambarus emegi 

Lieb, Williams, Foltz & Loughman, 2026 

 

DOI: doi.org/10.11646/zootaxa.5857.2.5 

  facebook.com/WLUCrayfish

Abstract

A new species of crayfish, Cambarus emegi sp. nov., is described from the upper James and Roanoke River basins in Virginia and the lower Delaware River basin in Pennsylvania, where it occurs in streams and small rivers. The species was formerly part of the Cambarus acuminatus species complex (Cambarus species C complex), a long-standing taxonomic enigma that is widely distributed across the Atlantic slope drainages of eastern North America. Cambarus emegi sp. nov. can be distinguished from Cambarus acuminatus due to the absence of a well-defined subpalmar tubercle, greater number of punctations across its areola, and differences in the mesial process of the form I male gonopod. Coloration and pattern in life differ between the two species. Additionally, the distributions of C. emegi sp. nov. and C. acuminatus are separated by hundreds of kilometers. The ranges of two other undescribed members of the Cambarus species C complex border that of C. emegi sp. nov. in Virginia. These species do not appear to overlap geographically; C. emegi sp. nov. is confined to the Ridge and Valley physiographic province, whereas the two undescribed species are found in the Blue Ridge and northern inner Piedmont regions. Cambarus emegi sp. nov. is morphologically similar but visually and genetically different from the undescribed species directly to the south in the upper Roanoke River system. Cambarus emegi sp. nov. is both visually and morphologically similar but genetically distinct from the undescribed species immediately downstream in the James River basin. Cambarus emegi sp. nov. is threatened by several potentially interacting factors including invasive crayfishes, narrow range, and urban and agricultural development. Alarmingly, the species is being rapidly replaced by invasive Faxonius species across a substantial part of its range. This paper represents an important step in providing the information needed to conserve and manage Cambarus emegi sp. nov.

Crustacea, Cambarus species C., Cambarus acuminatus, new species, Ridge and Valley, Northern Piedmont, Delaware, James, Roanoke, invasive crayfish

 Cambarus emegi sp. nov., color in life: (a) holotype, NCSM 95987; (b) allotype, NCSM 95988.

Life color and color pattern of adult  Cambarus emegi sp. nov.:
 (a) dorsal view; (b) oblique lateral view (photo credit Zackary A. Graham).

 Life color and color pattern of juvenile  Cambarus emegi sp. nov. 

Cambarus emegi sp. nov. 

Diagnosis.—Body and eyes pigmented. Rostrum weakly to moderately excavated and ventrally deflected anteriorly; rostral margins subparallel, pronounced and entire through acumen, and more thickened posteriorly than anteriorly; acumen acuminate with prominent dorsally deflected spiniform tubercle at terminus. Areola 2.2–3.6 (¯x=2.7, n=42, s=0.4) times as long as wide, with 6–10 (¯x=8.5, n=42, s= 0.7) punctations across narrowest point. Lateral portion of branchiostegal region of carapace heavily punctate; hepatic regions also punctate with welldeveloped tubercles. Strong cervical spines present; branchiostegal spine prominent; postorbital ridge terminating anteriorly in spiniform tubercle or spine. Weak to acute suborbital angle typically present, rarely absent; suborbital angle terminating anteriorly in spiniform tubercle or spine. Antennal basipodite spines prominent; ischiopodite spines present but not prominent.

Etymology.—Derived from the Turkish work “emeği” meaning “labor of” or “hard work of”, which seems appropriate given this project required many years and the collection of thousands of specimens from South Carolina to Pennsylvania. Additionally, the name honors Emily (Em) and Megan (Meg) Lieb, the senior author’s two daughters, who happily accompanied him on many crayfish sampling trips as children and later helped him collect C. emegi sp. nov. from sites in its Pennsylvania range. 

Common name.—We propose Enigma Crayfish as the common name.

David A. LIEB, Bronwyn W. WILLIAMS, David A. FOLTZ II and Zachary J. LOUGHMAN. 2026. Description of A New Stream-dwelling Species of Cambarus (Decapoda: Cambaridae) from Virginia and Pennsylvania (USA) with Notes on its Distribution, Ecology, and Conservation Status.  Zootaxa. 5857(2); 299-316. DOI: doi.org/10.11646/zootaxa.5857.2.5 [2026-07-29]

 facebook.com/WLUCrayfish/posts/1731022025695189 

[Paleontology • 2026] Spea labreae • A New extinct Pleistocene Species of Spadefoot Toad (Anura: Scaphiopodidae) and comments on the Paleoecology and Paleobiogeography of Anurans from Rancho La Brea, California

Reconstruction of Spea labreae, (dark spadefoots, center) in La Brea Tar Pits compared with Spea hammondii (light spadefoot, left), the species currently present in the area, and the presence of the Mexican burrowing toad (Rhinophrynidae, bottom). 

 Cruz & Lindsey, 2026

 DOI: doi.org/10.1080/02724634.2026.2689465 

Artwork by Arturo Dávalos

ABSTRACT

Fossil amphibians hold great promise for paleoecological, paleoclimatological, and biogeographic studies because of their extreme sensitivity to environmental conditions. However, the study of fossil amphibians to date has been limited, because the fragility of frog, toad, and salamander skeletons means that diagnostic elements are rarely preserved in the fossil record. One unique locality that preserves a robust record of Quaternary amphibians is Rancho La Brea in Los Angeles, California, U.S.A. Here, we describe the amphibian fauna from the Hancock Collection of Rancho La Brea, which contains fossils from ∼45,000 years before present through the Holocene. We document previously unrecognized taxa from this locality, including the Mexican burrowing toad Rhinophrynus sp. and a new species of spadefoot toad, Spea labreae, sp. nov. Using osteological comparison material, we calculate the size of this new species of Spea, which is larger than the extant species in this genus. We analyze the current distribution and fossil record of the genus Spea and the family Rhinophrynidae, documenting changes in geographic ranges of these taxa during the Quaternary. These changes likely resulted from the interplay of deglacial climate changes and topographic complexity in the American Southwest, and may help to predict amphibian responses to climate changes impacting the region today.

Class AMPHIBIA, Linnaeus, 1767

Order ANURA Rafinesque, 1815

Family SCAPHIOPODIDAE Cope, 1865

Genus SPEA Cope, 1866

SPEA LABREAE, sp. nov.

Etymology—The specific epithet refers to La Brea, Spanish for ‘the tar’ which gave rise to the name of Rancho La Brea, the locality where this species is found.

 

Locality, Horizon, and Age—Pit A, Rancho La Brea, Los Angeles, California, Late Pleistocene–Holocene.

 

Reconstruction of Spea labreae, (dark spadefoots, center and right) in La Brea Tar Pits compared with Spea hammondii (light spadefoot, left), the species currently present in the area, and the presence of the Mexican burrowing toad (Rhinophrynidae, bottom).

 Artwork by Arturo Dávalos.

 

J. Alberto Cruz and Emily L. Lindsey. 2026. A New extinct Pleistocene Species of Spadefoot Toad and comments on the Paleoecology and Paleobiogeography of Anurans from Rancho La Brea, California. Journal of Vertebrate Paleontology. e2689465. DOI: doi.org/10.1080/02724634.2026.2689465 [04 Aug 2026]

[Crustacea • 2025] Cambarus ocoeensis • A New Species of Crayfish (Decapoda: Cambaridae) from the Ocoee River Basin of Tennessee, USA

 

Cambarus ocoeensis 

 Thoma & Williams, 2025 

DOI: doi.org/10.11646/zootaxa.5618.1.7  

  Researchgate.net/publication/390392403 

  facebook.com/RogerFThoma

Abstract

Cambarus ocoeensis sp. nov. is described from the Ocoee River Gorge area of Tennessee. The species is morphologically most similar to Cambarus hiwasseensis Hobbs, 1981, but differs from C. hiwasseensis in the following ways: first pereopod chelae in general less sculpted, usually with one row of palmer tubercles, if second row present very weakly developed and consisting of six or fewer tubercles, lateral margin not costate, lateral impression weak at most but usually absent; areola length 2.5–4.1 times greater than width, having 5–8 punctations in narrowest part; size at maturity smaller with MI ranging from 21.8 to 30.9 mm total carapace length (24.6–40.0 mm in C. hiwasseensis); and antennal scale broadest at midpoint. It can be distinguished from other morphologically similar species—those with acuminate rostra—from the Hiwassee River basin of northern Georgia, southeast Tennessee, and western North Carolina area in lacking lateral rostral spines/tubercles and cervical spines. Cambarus ocoeensis sp. nov. is genetically most closely related to an undescribed member of the Cambarus bartonii (Fabricius, 1798) species complex.

 

Crustacea, C. hiwasseensis, C. bartonii, C. howardi, Hiwassee River basin, species complex

Type material of Cambarus ocoeensis sp. nov.:
 A–C, E, G–I, holotype MI (OSUMC #10897); F, allotypic paratypefemale (OSUMC #10898); D, morphotypic paratype MII (OSUMC #10899).
A–carapace, dorsal view; B–gonopod, lateralview; C–gonopod, mesial view; D–gonopod, lateral view; E–antennal scale, dorsal view; F–annulus ventralis; G–pereopods3–5, right side ventral views; H–epistome; I–right chela, dorsal view. 

Color image of Cambarus ocoeensis sp. nov., holotype (OSUMC #10897).

Image captured in lab under artificial light.

Cambarus ocoeensis sp. nov. 

Roger F. THOMA and Bronwyn W. WILLIAMS. 2025. Cambarus ocoeensis, A New Species of Crayfish (Decapoda: Cambaridae) from the Ocoee River Basin of Tennessee, USA.  Zootaxa. 5618(1); 106-118. DOI: doi.org/10.11646/zootaxa.5618.1.7 [2025-04-01] 

 Researchgate.net/publication/390392403_Cambarus_ocoeensis_a_new_species_of_crayfish_from_the_Ocoee_River_Basin_of_Tennessee_USA

  facebook.com/RogerFThoma/posts/10228373600190065

[Botany • 2026] Syngonium turipachense (Araceae) • A New Species of Syngonium sect. Syngonium from Chiapas, Mexico

Syngonium turipachense 

in Jiménez, Pérez-Farrera, Croat, Martínez-Martínez, Méndez, Hentrich et Aguilar-Rodríguez, 2026.

 DOI: doi.org/10.11646/phytotaxa.750.3.6 

   facebook.com/Unicach

 

The genus Syngonium is represented in Mexico by ten species, seven of which are registered for the state of Chiapas. During fieldwork between 2020 and 2025 in Berriozabal, Chiapas, we discovered an undescribed species of Syngonium sect. Syngonium that is morphologically similar to S. neglectum, but differing from that species in having one or two inflorescences per axil, glaucous stems and spathe tube, a spathe blade almost twice as long as the staminate portion of the spadix, staminate flowers retuse at the apex, glaucous immature infructescence and the spathe not persistent in mature fruits.

Aroid, Berriozabal, Reserva La Pera, Syngonium angustatum, Syngonium neglectum, Monocots

Syngonium turipachense

PEDRO DÍAZ JIMÉNEZ, MIGUEL ÁNGEL PÉREZ-FARRERA, THOMAS B. CROAT, MAURICIO GERÓNIMO MARTÍNEZ-MARTÍNEZ, GASPAR MORENO MÉNDEZ, HEIKO HENTRICH, PEDRO A. AGUILAR-RODRÍGUEZ. 2026. A New Species of Syngonium sect. Syngonium (Araceae) from Chiapas, Mexico.  Phytotaxa. 750(3); 207-215. DOI: doi.org/10.11646/phytotaxa.750.3.6 [2026-04-07]

  facebook.com/Unicach/posts/1360714109410395

[Entomology • 2026] Oxyporus amigo • A New Species of Oxyporus Fabricius (Coleoptera: Staphylinidae: Oxyporinae) from western Mexico

 

 Oxyporus amigo

Navarrete-Heredia & Reyes-Hernández, 2026

 DOI: doi.org/10.11646/zootaxa.5837.1.7

Abstract

A new species, Oxyporus amigo, is described from Jalisco and Michoacán, Mexico. The new species is diagnosed and illustrated. Additionally, Oxyporus mexicanus Fauvel, 1865 is recorded for the first time from the state of Aguascalientes, based on specimens collected in Monte Grande, San José de Gracia.

Coleoptera, Oxyporinae, rove beetles, taxonomy, new species, Trans-Mexican Volcanic Belt

Habitus of Oxyporus amigo sp. nov.:
 1) holotype, male, dorsal view; 2) paratype, female, dorsal view. Scale bars: 1 mm

Aedeagus of Oxyporus amigo sp. nov. (holotype, male);
3) Parameral view; 4) Left lateral view; 5) Right lateral view; 6) Antiparameral view.

Scale bars: 1 mm.

JOSÉ L. NAVARRETE-HEREDIA and JOSÉ L. REYES-HERNÁNDEZ. 2026. A New Species of Oxyporus Fabricius (Coleoptera: Staphylinidae: Oxyporinae) from western Mexico and New Record from Aguascalientes for O. mexicanus Fauvel. Zootaxa. 5837(1); 154-160. DOI: doi.org/10.11646/zootaxa.5837.1.7 [2026-06-22]

[Arachnida • 2026] Trogloraptor tulishpun • A New northern Species of Trogloraptor (Araneae: Trogloraptoridae), Genetic Diversity and Natural History

 

 Trogloraptor tulishpun Jones & Binford,

in Jones, Watson, Hedin et Binford, 2026.

DOI: doi.org/10.11646/zootaxa.5828.1.5 

photos by M. Hedin

Abstract

We present a morphological description of a recently discovered species of spider in the family Trogloraptoridae from the Columbia River Gorge in northwestern Oregon. The family was previously monotypic (Trogloraptor marchingtoni) and only known from populations near the southwestern Oregon—northern California border. Trogloraptor tulishpun sp. nov. retains the key family synapomorphy, distinctive subsegmented raptorial tarsi, and an oblique membranous division of the basal segment of the anterior lateral spinnerets. Trogloraptor tulishpun is distinguished from T. marchingtoni by its color pattern, clypeal height, vulvar and palp structure. We have found T. tulishpun in four localities in the Columbia River Gorge, which show little mitochondrial sequence divergence from one another, but are highly genetically distinct from T. marchingtoni. Trogloraptor tulishpun is found in basalt features, including lava tubes and shallow talus caves, and has been observed to eat arachnids and moths, making them top predators in these environments.

Araneae, arachnophagy, caves, invertebrate conservation, mitochondrial divergence, subterranean biodiversity

Habitus of live Trogloraptor tulishpun from Herman Creek Talus Cave.
A male in captivity, B female in captivity,
C male in Herman Creek Talus Cave, D female in Herman Creek Talus Cave on sparse web,
 E male on non Trogloraptor web, F female in Herman Creek Talus Cave.

(all photos by M. Hedin)

Habitus of male Trogloraptor tulishpun (holotype, USNMENT02418340) from Herman Creek Talus Cave.
A, B dorsal views, C, E ventral views, D anterior view.

Trogloraptor tulishpun, Jones and Binford, sp. nov.  

Diagnosis. Trogloraptor tulishpun resembles T. marchingtoni (Griswold et al., 2012) by its similar carapace and abdominal shape and coloration, its subsegmented raptorial tarsi, and the partly sclerotized genital region (Figs 2, 3, 5, 7). It is clearly distinguished by its conspicuous scalloped patterning along the lateral and posterior edges of the carapace which is absent in T. marchingtoni. The abdominal patterning is different from the chevron pattern of T. marchingtoni, with oval-shaped spots down the center of the dorsal side that have a thin line of beige down the ...

Etymology. Tulishpun (pronounced too-lish-pun) is a word, simplified for ease of pronunciation, from the Sahaptin River dialect meaning “cave predator, owner of the domain”. The Sahaptin River dialect is from the Columbia River area, the type locality of this species, and the name was given to us by elders from the Columbia River Inter-Tribal Fish Commission. The specific epithet is to be treated as a noun in apposition.

 

MADELINE M. JONES, FINN WATSON, MARSHAL HEDIN and GRETA J. BINFORD. 2026. Beneath the Surface: A New northern Species of Trogloraptor (Araneae: Trogloraptoridae), Genetic Diversity and Natural History.  Zootaxa. 5828(1); 103-116. DOI: doi.org/10.11646/zootaxa.5828.1.5 [2026-06-08]

[Paleontology • 2026] Labrujasuchus expectatus • A New shuvosaurid (Archosauria: Poposauroidea) from the Late Triassic (Norian) Hayden Quarry of New Mexico, U.S.A.

Labrujasuchus expectatus

Turner, Kernan, Laing, Pritchard, Stocker, Irmis, Smith, Werning & Nesbitt, 2026

DOI: doi.org/10.1080/02724634.2026.2618182

Artwork: Jorge Gonzalez/NHMLAC Dinosaur Institute

ABSTRACT

Bipedal shuvosaurid archosaurs were present for much of the Late Triassic Period. The clade is particularly diverse in Upper Triassic assemblages in the western U.S.A. Isolated bones are easily differentiated from contemporary archosaurs, but the two named North American species, Shuvosaurus inexpectatus and Effigia okeeffeae, display remarkably similar skeletons. Here we describe a new shuvosaurid species, Labrujasuchus expectatus, gen. et sp. nov., from the middle Norian (∼212 Ma) Hayden Quarry of northern New Mexico, U.S.A., located within the Petrified Forest Member of the Chinle Formation, that fills the temporal gap between the two species. The holotype consists of a partial skeleton, with additional shuvosaurid material from the Hayden Quarry likely pertaining to this taxon. This taxon is distinguished by four autapomorphies and assignable to Shuvosauridae based on a deep fossa present on the posterodorsal edge of the coracoid, the proximal portion of the humerus less than twice the width of the midshaft, the anteromedial tuber of the femur large and ‘hooked’ posteriorly, and a ventrally descended posterolateral portion of the femoral head. Recent Bayesian estimates of archosaur phylogeny and divergence times suggested a Middle Triassic split for Shuvosauridae as well as a decrease in the rate of morphological evolution for the clade relative to that of other archosaurs. The anatomical similarity of L. expectatus with other shuvosaurids is consistent with these estimated low rates, and the long gaps in the fossil record for the clade suggest that much of their evolutionary history remains to be sampled.

Reconstruction of Labrujasuchus expectatus, a new species of Shuvosauridae from Late Triassic rocks of Ghost Ranch, New Mexico.

Artwork: Jorge Gonzalez/NHMLAC Dinosaur Institute

SYSTEMATIC PALEONTOLOGY

ARCHOSAURIA Cope, 1870 (sensu Gauthier & Padian, 1985)

SUCHIA Krebs, 1974 (sensu Benton & Clark 1988)

SHUVOSAURIDAE Chatterjee, 1993 (sensu Nesbitt, 2011)

LABRUJASUCHUS gen. nov.

Type Species—Labrujasuchus expectatus

Etymology—The generic name Labrujasuchus (“la-broo-ha-soo-kus”) is derived from “Ranchos de los Brujos,” Ranch of the Witches, an old Spanish name for the Ghost Ranch area, and the Greek word Σοῦχος (suchus) meaning “crocodile.” It is masculine in gender.

 

LABRUJASUCHUS EXPECTATUS sp. nov.

Etymology—From the Latin “expectatus” for expected or awaited.

The species name is based on the anticipated nature of a shuvosaurid discovery at the Hayden Quarry.

Alan H. Turner, Ciara E. Kernan, Adam Laing, Adam C. Pritchard, Michelle R. Stocker, Randall B. Irmis, Nathan D. Smith, Sarah Werning and Sterling J. Nesbitt. 2026. A New shuvosaurid (Archosauria, Poposauroidea) from the Late Triassic (Norian) Hayden Quarry of New Mexico, U.S.A. Journal of Vertebrate Paleontology.  e2618182 DOI: doi.org/10.1080/02724634.2026.2618182  [26 May 2026]

[Botany • 2026] Dioon nuusaviorum (Zamiaceae) • A striking New Species from pine and pine-oak forest of Guerrero, Mexico

Dioon nuusaviorum Mart.-Domínguez, Nic.-Mor. & D.W.Stev.,   

in Martínez-Domínguez, Nicolalde-Morejón, Stevenson, Lorea-Hernández et Vergara-Silva, 2026.

DOI: doi.org/10.3897/phytokeys.274.173907 

Abstract

Taxonomic studies in cycad genera using multiple approaches have refined the delimitation of many species. In the case of Dioon Lindl., a Mesoamerican genus, a reliable classification has been achieved through taxonomic work carried out since the description of the genus and pioneering studies in Mexico during the 1980–90s. Here, we describe a new species from Guerrero based on evidence collected from populations encountered during fieldwork carried out in 2019. These populations had previously been considered morphologically similar to Dioon holmgrenii De Luca, Sabato & Vázq. Torres, which has a markedly disjunct distribution in Oaxaca. After studying herbarium specimens and making extensive observations on vegetative and reproductive structures from different populations in Oaxaca, we have concluded that the disjunct populations analysed in 2019 represent a distinct and new species of Dioon, separate from the two most phenotypically similar species—namely, D. stevensonii Nic.-Mor. & Vovides and D. holmgrenii. A key to geographically proximal and morphologically similar species as well as to the other species occurring in Guerrero and Oaxaca States is also presented. The proposed new species, Dioon nuusaviorum Mart.-Domínguez, Nic.-Mor. & D.W.Stev., is endemic to Guerrero and inhabits pine and pine-oak forest. Its conservation status, assessed on the based IUCN guidelines and criteria, qualifies as Endangered.

Key words: Cycadales, cycads, Mesoamerica, Neotropics, Sierra Madre del Sur

Dioon nuusaviorum sp. nov.
A. Ovulate strobilus; B. Megasporophyll; C. Basal scale of megasporophyll; D. Microsporophyll; E. Leaflets variation; F. Cataphylls; G. Seeds variation; H. New leaves; I. Leaves at emergence; J. Leaf at maturity.

Dioon nuusaviorum sp. nov., in habitat.
 A. Ovuliferous plant in habitat; B. Eumaeus sp; C. Population in La Trinidad; D. Vegetation view; E. Ovulate strobilus at maturity in habitat. 

Dioon nuusaviorum Mart.-Domínguez, Nic.-Mor. & D.W.Stev., sp. nov.

 

Diagnosis. Dioon nuusaviorum sp. nov. differs from D. holmgrenii by having leaflets imbricate to strongly imbricate, each with three to six long marginal teeth (0.26–0.37 cm long), a margin of the leaflets curved acroscopically, microsporophylls with an acuminate apex and megasporophylls with an apiculate apex. In contrast, D. holmgrenii has non-imbricate leaflets (generally a 0.2–1.0 cm between leaflets) with two to five short teeth on the distal margin (0.15–0.29 cm long), a margin of the leaflets straight, microsporophylls with an acute apex and megasporophylls with an acuminate apex. In comparison to D. stevensonii, this new species differs by its light green leaflets at emergence (vs golden), leaflet imbricate to strongly imbricate (vs not imbricate), acuminate apex of microsporophylls (vs acute), tomentose indument and narrowly-triangular megasporophylls at maturity (vs pubescent at base or scarcely pubescent and triangular).

Comparison of leaflets of Dioon holmgrenii, D. stevensonii and Dioon nuusaviorum sp. nov.
A. D. stevensonii; B. D. holmgrenii; C. Dioon nuusaviorum sp. nov.;
D. D. stevensonii (F. Nicolalde-Morejón et al. 1554, CIB); E. D. holmgrenii (Brigada T. Walters s/n [3997], XAL); F. D. holmgrenii (F. Nicolalde-Morejón et al. 1468, XAL); G. Dioon nuusaviorum sp. nov. (L. Martínez-Domínguez et al. 1745, CIB).

 Lilí Martínez-Domínguez, Fernando Nicolalde-Morejón, Dennis Wm. Stevenson, Francisco G. Lorea-Hernández and Francisco Vergara-Silva. 2026. A striking New Species of Dioon (Zamiaceae) from pine and pine-oak forest of Guerrero, Mexico. PhytoKeys. 274: 229-245. DOI: doi.org/10.3897/phytokeys.274.173907 [11 May 2026]

[Paleontology • 2026] Tylosaurus rex • A gigantic New Species of Tylosaurus (Squamata: Mosasauridae) from Texas: and A revised character list for phylogenetic analyses of Mosasauridae

Tylosaurus rex

Zietlow, Polcyn & Tykoski, 2026

 

hdl.handle.net/2246/7549 

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Abstract

At least four subfamily-level clades of mosasaurs are broadly recognized (Mosasaurinae, Plioplatecarpinae, Tylosaurinae, Halisaurinae), each of which independently evolved flippers and other aquatic adaptations, including large body size. Tylosaurine mosasaurs are distinguished from other mosasaurs, in part, by edentulous extensions of both upper and lower jaws, proportionally long tails, and poorly ossified limbs, and they were the first mosasaur clade to achieve gigantic (>8 m) body size. Several tylosaurine species are known from Europe, Asia, New Zealand, Africa, and Antarctica, but they were most common in the Western Interior Seaway of North America. Here, we describe a new species, Tylosaurus rex, sp. nov., from the Campanian of Texas and analyze tylosaurine in-group systematics using a significantly updated phylogenetic character list. Our new species is distinguished by a unique suite of characters, including some associated with increased jaw and neck musculature, and others that may be convergent with other giant mosasaur species (e.g., Mosasaurus). Body length estimates for specimens referred to our new species are consistently larger (7.7–13.2 m) than those for the largest Niobrara species, T. proriger (3.9–9.5 m), although it is unclear whether this is a taxonomic signal or taphonomic bias. Several specimens that we refer to T. rex were previously referred to T. proriger in various collections databases, and some of the traits distinguishing them had been previously attributed to ontogenetic differences. However, we rule out this possibility as specimens of T. proriger and T. rex that do overlap in size can be differentiated by unique suites of diagnostic characters. The implicit association between body size and ontogeny, as well as the general absence of reliable locality and stratigraphic data associated with historical collections of North American mosasaurs, raises the possibility of the presence of other currently unrecognized species, previously dismissed as ontogenetic stages of other species.

 

Keywords: Tylosaurus rex, Tylosaurus, Texas, Classification, Mosasauridae, Phylogeny 

The holotype for the newly described Tylosaurus rex is a giant specimen displayed at the Perot Museum of Nature and Science in Dallas that was first discovered in 1979.

 Perot Museum of Nature and Science

Tylosaurus rex, sp. nov.

A reconstruction of Tylosaurus rex in the Cretaceous-era Western Interior Seaway of North America

artwork by Alderon Games - Path of Titans

Zietlow, Amelia R.; Polcyn, Michael J. and Tykoski, Ronald S. 2026. A gigantic New Species of Tylosaurus (Squamata, Mosasauridae) from Texas: and A revised character list for phylogenetic analyses of Mosasauridae. Bulletin of the American Museum of Natural History. 482; DOI: 10.1206/0003-0090.482.1.1 https://hdl.handle.net/2246/7549

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