[Paleontology • 2026] Austronaga minuta • Highly aquatic marine stem Archosaur with soft tissue preservation

Austronaga minuta Wang, Lei & Li, 2023

 

in Wang, Fraser, Spiekman, Z. Li, et C. Li, 2026. 

DOI: doi.org/10.1126/sciadv.aeb7528 

Artwork by Gabriel Ugueto

 

Abstract

Archosauromorpha is a dominant reptile clade that primarily occupied terrestrial ecosystems with limited secondarily aquatic invasions that are poorly known. Here we report on a well-preserved Triassic reptile representing the earliest stem-archosaur to evolve unequivocal aquatic specializations. This taxon exhibits a suite of aquatic adaptations previously unknown in stem-archosaurs, such as hyperphalangy, enhanced paddle-like forelimbs, and a loss of articulation between the sacrum and pelvis, indicating an advanced aquatic lifestyle. The fossil exhibits the oldest known stomach, liver, and intestinal preservations in reptiles. Our findings provide unexpected insights into the early aquatic diversification of Archosauromorpha during the Triassic marine ecosystem recovery and highlight a conservative gastrointestinal system in an early Mesozoic vertebrate. In the absence of clear terrestrial members of the other major Mesozoic marine reptile lineages (e.g., ichthyosaurs and sauropterygians), this discovery provides an unambiguous example of such a lineage including both decidedly terrestrial and extensively marine forms, providing tantalizing evidence for the land-to-sea transition in Triassic reptiles.

Systematic paleontology

Diapsida, Osborn, 1903.

Archosauromorpha, von Huene, 1946.

Tanysauria, Spiekman et al., 2024.

Trachelosauridae, Abel 1919 (sensu Spiekman et al., 2024).

Skeleton of the holotype of Austronaga minuta (IVPP V18579). Abbreviations are in the Supplementary Materials. Scale bars, 2 cm (A) and 1 cm (B to D).

Austronaga minuta, Wang et al., 2023.

Type specimen: Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) V18579, a complete articulated skeleton preserved on two slabs (Fig. 1).

Locality and horizon: Waina Village, Luoping County, Yunnan Province, China; Member II of Guanling Formation, middle Anisian (Pelsonian), Middle Triassic.

Emended diagnosis: A tanysaur with the following features: quadrate anteroposteriorly broad and plate-like in lateral view with concave posterior margin; 18 cervical, 24 dorsal vertebrae; tall axe-shaped neural spine on axis; cervical neural spines prominent, with convex dorsal margin and without anterodorsal or posterodorsal projections; chevrons of mid-caudal region hatchet-shaped, with prominent distal expansion and a notch at the midpoint of its ventral margin; forelimb distinctly longer than hindlimb with humerus to femur length ratio over two; hyperphalangy present in both manus and pes.

Reconstruction of the long-necked marine reptile Austronaga minuta.

Artwork by Gabriel Ugueto

Wei Wang, Nicholas C. Fraser, Stephan N. F. Spiekman, Zhiheng Li, Olivier Rieppel, Hong Lei, Torsten M. Scheyer and Chun Li. 2026. Highly aquatic marine stem Archosaur with soft tissue preservation. Science Advances. 12(31); DOI: doi.org/10.1126/sciadv.aeb7528 [29 Jul 2026]

[Paleontology • 2026] Cicero spectabilis • Aptian archaeoniscid isopod from the Araripe Basin supports Tethyan-linked dispersal into Gondwanan lacustrine systems

Cicero spectabilis 

Lima, Anker, Heads, Pinheiro & Santana, 2026 

DOI: doi.org/10.1038/s41598-026-59890-0

Life reconstruction of Cicero spectabilis n. gen. n. sp. in the Aptian lacustrine environment of the Crato Formation, Araripe Basin, Brazil, showing several individuals scavenging on a dead fish (Dastilbe) on the lake floor, surrounded by aquatic vegetation (Notocyamus hydrophobus), fishes and arthropods.  

 Illustration by Maurílio Oliveira (paleoartist, MN/UFRJ).

Abstract

A new genus and species of fossil isopod, Cicero spectabilis n. gen. n. sp. is described from the Early Cretaceous (Aptian) Nova Olinda Member of the Crato Formation, Araripe Sedimentary Basin, Ceará, northeastern Brazil. The holotype, preserved in laminated limestones, represents the first confirmed record of the family Archaeoniscidae within this stratigraphic unit and extends the previously known paleogeographic distribution of archaeoniscid-like isopods into Gondwana lacustrine settings. The new genus is distinguished from other taxa currently referred to Archaeoniscidae—Archaeoniscus, Ferreniscus and Codoisopus, by its broad, ovate body, distinctive antennular subdivision, and a fan-like caudal structure formed by birramous uropods with well-differentiated exopod and endopod, combined with a rounded subrectangular pleotelson bearing a row of posterior setae. The exceptional preservation of C. spectabilis n. gen. n. sp. enables a detailed assessment of functionally relevant characters and supports interpretation of a benthic lifestyle on soft, low-energy substrates. A conservative concept of the family and a combination of body, pleon-pleotelson and antennular features justifies the placement of Cicero n. gen. within this extinct sphaeromatidean lineage. Within this framework, the occurrence C. spectabilis n. gen. n. sp. in a stratified lacustrine system of the Araripe Basin, together with other Mesozoic archaeoniscid-like records, suggest that some lineages currently assigned to Archaeoniscidae were able to colonize a range of non-marine environments during the Early Cretaceous, while also underscoring the need for a comprehensive phylogenetic reassessment of the group.

Keywords: Malacostraca, Sphaeromatidea, Fossil isopod, Crustacean, Santana group, Archaeoniscidae, Crato formation

Holotype of Cicero spectabilis n. gen. n. sp. from the Aptian Nova Olinda Member of the Crato Formation, Araripe Basin, Brazil (MPSC 9701). A, Ventral view of the specimen preserved in laminated limestone. B, Interpretative line drawing highlighting cephalic appendages, pereopods, pleon, pleotelson, and uropods. Scale bars: 2 mm.

Cicero spectabilis n. gen. n. sp.

Life reconstruction of Cicero spectabilis n. gen. n. sp. in the Aptian lacustrine environment of the Crato Formation, Araripe Basin, Brazil, showing several individuals scavenging on a dead fish (Dastilbe) on the lake floor, surrounded by aquatic vegetation (Notocyamus hydrophobus), fishes and arthropods. Coloration and most dorsal features are conjectural and based on extant sphaeromatidean isopods. Illustration by Maurílio Oliveira (paleoartist, MN/UFRJ).

Daniel Lima, Arthur Anker, Sam W. Heads, Allysson P. Pinheiro and William Santana. 2026. Aptian archaeoniscid isopod from the Araripe Basin supports Tethyan-linked dispersal into Gondwanan lacustrine systems. Scientific Reports. 16: 23631. DOI: doi.org/10.1038/s41598-026-59890-0 [19 July 2026]

 

[Ichthyology • 2026] The prolonged Reemergence of Megapredatory Pelagic Fishes

  

the diversification of living large-bodied (> 2 m) marine predatory fishes such as tunas and mackerels (Scombridae)

in Brownstein, Alencar, Kindsvater, Thacker, Wainwright, Near et Harrington, 2026. 

DOI: doi.org/10.1098/rspb.2026.1257 

 x.com/ChaseBrownstein

 

Abstract

The assembly of modern ocean ecosystems was fundamentally affected by the Cretaceous–Palaeogene (K-Pg) mass extinction. Among the casualties of this event were many extinct clades of large pelagic predatory fishes. The extinction of these lineages is thought to have created ecological opportunity that spurred the diversification of living large-bodied (> 2 m) marine predatory fishes such as tunas and mackerels (Scombridae). However, it remains unclear whether a large, endothermic body plan evolved in tunas and mackerels directly after the K-Pg boundary or in a stepwise manner throughout the Cenozoic. Here, we demonstrate that Scombridae, which includes half of living endothermic ray-finned fish species, evolved endothermy and large body sizes long after the initial radiation of the clade at the K-Pg boundary. Our time-calibrated phylogeny also reveals that the origins of endothermy, large body size and increased longevity in true tunas are staggered over evolutionary time. These findings indicate that the evolution of large endothermic scombrids was not triggered by the K-Pg extinction and substantiate the protracted development of the endothermic predatory body plans of tunas and relatives over more than 50 million years of evolutionary history.

Keywords: Scombridae, tunas, phylogenomics, K-Pg mass extinction, endothermy

Origin of large body sizes in Scombridae. The phylogeny is coloured according to the ancestral state reconstruction for log-transformed standard length. Warmer colours indicate body sizes approaching 4 m. Body size increases over 2 m are denoted by Roman numerals. The innermost dashed circle indicates the K-Pg boundary. Illustrations of scombrids are by Julie Johnson (lifesciencestudios.com).

Tempo of trait shifts in Scombridae. Inferred histories of significant trait optima shifts across Scombridae plotted on the time-calibrated phylogeny of this clade. Shifts inferred with over 30% posterior probability are included. The full bayou outputs are in the electronic supplementary material associated with this article. Illustrations of scombrids are by Julie Johnson (lifesciencestudios.com).

Chase D. Brownstein; Laura R. V. Alencar; Holly K. Kindsvater; Christine E. Thacker; Dylan K. Wainwright; Thomas J. Near and Richard C. Harrington. 2026. The prolonged Reemergence of Megapredatory Pelagic Fishes.  Proc Biol Sci. 293 (2074): 20261257. DOI: doi.org/10.1098/rspb.2026.1257 [08 Jul 2026] 

 x.com/ChaseBrownstein/status/2074791152318865890

[Crustacea • 2026] Pachycheles ravichandrani • A New Species of Porcelain Crab (Decapoda: Porcellanidae) from Lakshadweep, India

 

Pachycheles ravichandrani 

Sureandiran, Radhakrishnan, S. Kumar & T. T. A. Kumar, 2026

DOI: doi.org/10.11646/zootaxa.5849.2.6 

 Researchgate.net/publication/409222030 

Abstract

A new species of porcelain crab, Pachycheles ravichandrani sp. nov. is described from specimens collected at Agatti Island, Lakshadweep, India. Pachycheles ravichandrani sp. nov. shares similar morphology with P. garciaensis (Ward 1942) and P. setiferous Yang, 1996 in the following characters: carapace with trilobed front, cheliped without setae, 5-plated telson and presence of a pair of pleopods in males. The new species, however, is differentiated by the presence of setae along lateral ridges and posterior margin of carapace, minor cheliped with distinct gap between fingers and cutting edge of minor cheliped truncate. To validate the taxonomic status of the new species, molecular analysis, using COI and 16S rRNA genes were carried out. Phylogenetic reconstruction consistently showed P. ravichandrani sp. nov. as a distinct, well-supported lineage separate from all congeners. Genetic divergence within the genus Pachycheles ranged from 12.6–21.7% (COI) and 4.0–13.7% (16S rRNA).

Crustacea, Crab, Integrative taxonomy, Indian Ocean, Lakshadweep reefs

Pachycheles ravichandrani sp. nov. in live condition, collected from Agatti Island, Lakshadweep. Specimen not preserved. Scale bar: 1 mm.

Pachycheles ravichandrani sp. nov., holotype male, PORPRAV/NBFGR, CW 3.69 mm.

 A, carapace, dorsal view; B, frontal lobe, frontal view; C, antennular peduncle, dorsal view; D, antennule basal segment, dorsal view; E, maxilliped 3, ventral view; F, thoracic sternite, ventral view; G, pleopod, dorsal view. 

Scale bars: A, B, F = 1 mm; C–E, G = 0.5 mm.

 A, major cheliped, dorsal view; B, fingers of major cheliped, closer view; C, minor cheliped, dorsal view (paratype male, PORPRAV/NBFGR.1); D, fingers of minor cheliped, closer view (paratype male); E, P2, lateral view; F, P3, lateral view; G, P4, lateral view; H, P5, lateral view. 

Scale bars: A–D = 1 mm; E–H = 0.5 mm.

Pachycheles ravichandrani sp. nov. 

BALAMURUGAN SUREANDIRAN, DIVYA PREMA RADHAKRISHNAN, SENDHIL KUMAR and THIPRAMALAI THANGAPPAN AJITH KUMAR. 2026. Pachycheles ravichandrani, A New Species of Porcelain Crab from Lakshadweep, India (Crustacea: Decapoda: Porcellanidae).  Zootaxa. 5849(2); 227-238. DOI: doi.org/10.11646/zootaxa.5849.2.6 [2026-07-13]

 Researchgate.net/publication/409222030_Pachycheles_ravichandrani_a_new_species_of_porcelain_crab_from_Lakshadweep_India

[Crustacea • 2026] Harcledo toyoshioae • A New Species of Giant-eyed bathypelagic eusirid Amphipod (Amphipoda: Eusiridae) from the western North Pacific

 Harcledo toyoshioae 

 Kodama, Watabe, Nakaguchi & Wakabayashi, 2026

「オオメダマヨコエビ」 DOI: doi.org/10.1080/14772000.2026.2659885

Abstract

Deep-sea visual environments show extreme gradients in light intensity, driving divergence in eye morphology. In the order Amphipoda, such specializations are documented in pelagic hyperiideans, whereas deep-sea Eusiridae remain poorly known. During a bathypelagic survey in Japan, we collected a eusirid amphipod with conspicuously enlarged eyes. Integrative taxonomy, using morphology and four DNA barcoding regions, shows that it represents a new species of the monotypic genus Harcledo Barnard, 1964, described here as Harcledo toyoshioae sp. nov. It is characterized by markedly enlarged eyes that cover most of the lateral head and meet across the dorsal midline, and by a distinctive maxilla 1 armature. Phylogenetic analyses place H. toyoshioae sp. nov. within Eusiridae but leave its relationships to H. curvidactyla unresolved, owing to the lack of sequence data. Comparisons with historical records suggest rapid diversification of eye size within this clade and indicate that it is unlikely to be governed by depth or pelagic–benthic mode alone. We propose that the enlarged eyes are plausibly associated with a pelagic lifestyle in dim mid-water habitats, while noting that this interpretation remains tentative. Our findings highlight visual specializations in deep-sea eusirids and the value of combining new collections, historical literature, and molecular data when reassessing deep-sea taxa.

Key words: bathypelagic, deep sea, Harcledo, Kagoshima, Tanegashima Island, visual specialization

ORDER AMPHIPODA Latreille, 1816

FAMILY EUSIRIDAE Stebbing, 1888

Harcledo Barnard, 1964

 Harcledo toyoshioae sp. nov., paratype female, 18.8 mm, NSMT-Cr 33350, ethanol preserved specimen, photographs for head and pereonites 1–2: A, dorsal view; B, lateral view.

 Harcledo toyoshioae sp. nov., fresh specimens, lateral view:
A, holotype ovigerous female, 21.6 mm, NSMT-Cr 33349; B, paratype female, 18.8 mm, NSMT-Cr 33350.

Harcledo toyoshioae sp. nov.

DISTRIBUTION: Known only from type locality, North Pacific Ocean off Tanegashima Island, Kagoshima, Japan.

HABITAT: Bathypelagic zone (about 1200 m deep).

ETYMOLOGY: The new species is named after TRV Toyoshio Maru. The specific name is a noun in the genitive case.

Masafumi Kodama, Hiroto Watabe, Kazumitsu Nakaguchi and Kaori Wakabayashi. 2026. A New Species of Giant-eyed bathypelagic eusirid Amphipod (Crustacea: Amphipoda: Eusiridae) from the western North Pacific. Systematics and Biodiversity. 24(1); 2659885. DOI: doi.org/10.1080/14772000.2026.2659885 [05 Jun 2026]

[Ichthyology • 2026] Brachygobius jennie • A New bumblebee goby (Gobiiformes: Oxudercidae) from Hengqin Island, Guangdong Province, China

Brachygobius jennie  

 Tian, Wu, Lan, Lavoué & Huang, 2026. 

 DOI: doi.org/10.3897/zse.102.184142

Abstract

A new species of bumblebee goby, Brachygobius jennie sp. nov. (Teleostei, Oxudercidae), is described based on 31 specimens collected from the Hengqin Island, Guangdong Province, China. This new species is distinguished from all other valid species of Brachygobius by its extreme small size (SL < 9 mm) and distinctive number, position, size and shape of its black bars. It possesses four complete (forming ring) or nearly complete post-cephalic, relatively narrow bars, two of which are located posterior to the base of the anal fin. The first bar behind the head extends pigmentation to the first dorsal fin but does not reach the midventral line. The second bar, chevron-shaped and located below the second dorsal fin, extends pigmentation onto that fin and ventrally reaches the midventral line and the anal fin. Cytochrome oxidase subunit I-based analyses, including six out of the eight valid species of Brachygobius, show Brachygobius jennie sp. nov. to be more than 10% genetically divergent from other species, supporting the morphological diagnosis and confirming its distinct taxonomic status. With a maximum size of less than 9 mm SL (based on observations of 106 specimens), the new species is not only the smallest species of Brachygobius, but also one of the smallest known gobioid fishes.

Key Words: Fish, Gobioidei, integrative taxonomy, new species, miniature vertebrates

Diagnostic marking pattern comparison among all species of Brachygobius having four post-cephalic black bands, the last two located posterior to the base of the anal fin. Left column: schematic drawings highlighting diagnostic marking patterns based on information from type material and original descriptions; from top to bottom: 
Brachygobius jennie sp. nov. based on its description (this study); B. aggregatus, based on a drawing of a type specimen (plate 4 in Herre 1940); B. kabiliensis, based on the drawing of the holotype (fig. 19 in Inger 1958); and B. nunus, based on the drawing of a specimen of Gobius alcockii Annandale, 1906 (fig. 1 in Annandale 1906), a junior synonym of B. nunus, and the description of B. nunus by Hamilton (1822). Red arrowheads indicate diagnostic differences. Right column: photographs of live non-type specimens illustrating the corresponding left schematic patterns (all photos from the authors).

Live photographs of four paratypes of Brachygobius jennie sp. nov., illustrating intra-specific marking pattern.

Photographed by Mr. Haocong Yang and Mr. Danyang Zhou.

Brachygobius jennie sp. nov. 

 Jiangyan Tian, Jianyong Wu, Chunliu Lan, Sébastien Lavoué and Jianrong Huang. 2026. Brachygobius jennie, A New bumblebee goby (Teleostei, Oxudercidae) from Hengqin Island, Guangdong Province, China. Zoosystematics and Evolution. 102(3): 853-863.  DOI: doi.org/10.3897/zse.102.184142 [17 Jun 2026]

[Cnidaria • 2026] Hemicorallium osmanthogemmum • A New Species of Hemicorallium (Anthozoa: Octocorallia: Coralliidae), along with a revised identification key to species of the genus

Hemicorallium osmanthogemmum

Koido, 2026 

 

DOI: doi.org/10.3897/zookeys.1277.184620 

 

Abstract

A new precious coral species, Hemicorallium osmanthogemmum sp. nov. (Scleralcyonacea, Coralliidae), retrieved from a depth of 550 m in Kochi Prefecture, Japan, is described, and an updated identification key for the genus Hemicorallium is provided. The new species is confirmed as belonging to the genus Hemicorallium based on the presence of nonretractile but contractile autozooids with an ovate-cylindrical shape and sclerites comprising elongated rods, 6–8-radiates and double clubs, with elongated rods present exclusively in the tentacles. Moreover, the species is distinct from all its congeners in that it has orange coenenchyme and a pink axis, with autozooids distributed only on the front side of the branch, forming clusters at the branch tips. These morphological features differ from those of all previously described species of Hemicorallium, and molecular analysis of mitochondrial sequences (16S, ND1, ND2, ND3, ND6, COI, MSH, and IGR1) further corroborates the validity of this new species. This is the first report of Hemicorallium off the coast of Kochi Prefecture, Japan.

Key words: Cnidaria, deep-sea corals, precious coral, Scleralcyonacea, Western Pacific

 

Hemicorallium osmanthogemmum sp. nov. (Holotype: KBF-OA-00436).
 A. ‘‘Front’’ and ‘‘back’’ of colony; B. Branch, showing autozooid (AZ); C. Exposed axis with the coenenchyme removed; D, E. Surface detail of branch, showing autozooid (AZ), siphonozooid (SZ), burrows (Bu), cluster of autozooids (CL), warts on coenenchyme surface (W), and commensal polychaete (Po).

 Scale bars: 50 mm (A); 10 mm (B–E).

Class Octocorallia Haeckel, 1866

Order Scleralcyonacea McFadden, van Ofwegen & Quattrini, 2022

Family Coralliidae Lamouroux, 1812

Genus Hemicorallium Gray, 1867

Hemicorallium osmanthogemmum sp. nov. 

 New Japanese name. Kinmokusei-mizo-sango.

Diagnosis. The colony branches in one plane, and anastomoses are present only where broken branches come into contact with other branches. Autozooids are contracted but not retracted, and they are distributed only on one side of the colony. Spacing is almost absent on the twigs, and clusters are formed at the tips. The axis has no pits beneath the autozooids and is pale pink to pink in colour. Sclerites are predominantly radiate, and double clubs are rare. Warty rods are present only in the tentacles.

 

Tatsuki Koido. 2026. A New Species of Hemicorallium (Anthozoa, Octocorallia, Coralliidae), along with a revised identification key to species of the genus. ZooKeys. 1277: 339-354.  DOI: doi.org/10.3897/zookeys.1277.184620 [20 Apr 2026]

[Cnidaria • 2026] Paraplexaura binyuani • A New Gorgonian (Octocorallia: Acanthogorgiidae) from the Huaguang Atoll, Xisha Islands, South China Sea

 

Paraplexaura binyuani 

You, Xia & Liu, 2026. 

斌源似丛柳珊瑚  ||  DOI: doi.org/10.3390/d18030166 

Abstract

A new shallow-water gorgonian coral species in the family Acanthogorgiidae, Paraplexaura binyuani sp. nov., is described from a specimen collected at Huaguang Atoll in the South China Sea at a depth of 22 m. The new species is distinguished from its congeners by abundant polyp sclerites, predominantly flattened rods, and by the coenenchyme bearing numerous large spindles reaching up to 0.6 mm in length, which are approximately two to three times longer than those reported for most described species of Paraplexaura. Phylogenomic analyses based on ultraconserved elements (UCEs) recover Paraplexaura as monophyletic and place P. binyuani sp. nov. as sister to P. cryptotheca, consistent with its morphological distinctiveness and supporting its recognition as a separate species.

Keywords: Malacalcyonacea; shallow-water coral; taxonomy; morphology; ultraconserved elements

 The external morphology and polyps of Paraplexaura binyuani sp. nov. Holotype, GXTCMU-2025-HT005.
(A,C) in situ; (B) After collection; (D) Frontal view of a branch; (E) Polyps under SEM.

 Scale bars indicate 1 cm in (B), 5 mm in (D), 100 μm in (E).

Paraplexaura binyuani sp. nov.

Etymology. The new species is named after Dr. Binyuan He, principal investigator of the Guangxi Academy of Oceanography, and for his great contribution to benthos research of Guangxi. The Chinese name of the new species is “斌源似丛柳珊瑚”

Distribution and habitat. Known only from the subtidal zone of the Huaguang Atoll on the Chinese coast of the South China Sea with a water depth of 22 m. Colony attached to a rocky substrate.

 

Li You, Fei Xia and Xinming Liu. 2026. A New Gorgonian Paraplexaura binyuani sp. nov. (Cnidaria, Octocorallia, Acanthogorgiidae) from the Huaguang Atoll, Xisha Islands, South China Sea. Diversity. 18(3), 166. DOI: doi.org/10.3390/d18030166 [9 March 2026]

[Mollusca • 2026] Microeledone galapagensis • A New Species of Microeledone (Octopoda: Incirrata) from Galápagos Islands and an amended diagnosis of the Megaleledonidae

 

Microeledone galapagensis 

Voight, Smith, Buglass & Ziegler, 2026

DOI: doi.org/10.11646/zootaxa.5814.4.5 

 

Abstract

The octopod fauna of the deep tropical Pacific Ocean remains poorly known, as is the octopod family Megaleledonidae Taki. A single female megaleledonid specimen collected at 1773 m depth near the equatorial Galápagos island of Darwin is named Microeledone galapagensis sp. nov. This small, squat, short-armed octopod has few arm suckers and gill lamellae. Its lack of a crop diverticulum, ink sac, and anal flaps suggests that it pertains to Thaumeledone. However, its smooth skin, which dorsally is nearly free of pigment, large rachidian tooth, and large funnel organ ally it with the monotypic Microeledone. Its reverse countershading and dense pigmentation on the inner dorsal mantle musculature distinguish this species from Microeledone mangoldi Norman, Hochberg & Boucher-Rodoni, 2004a. This species belies the definition of the Megaleledonidae as large-bodied, Southern Ocean endemics, leading us to revise the family diagnosis. The short arms carrying few suckers in this genus and Thaumeledone are hypothesized to relate to heterochrony, potentially increasing energy available for reproduction and contributing to niche partitioning.

Mollusca, Thaumeledone, heterochrony, Pacific Ocean, deep sea, posterior salivary gland, ink sac, skin texture

Photos of Microeledone galapagensis sp.  nov. 
in situ (a); on recovery dorsal (b) and ventral (c) (photos by the Science Party of the NA064 cruise); in preservation dorsal (d) and ventral (e) views of entire animal. 

Microeledone galapagensis sp. nov. 

Diagnosis. With the characters of the genus; sheath covering inner dorsal mantle muscles heavily pigmented, internal organs lack pigment, except dots near mantle opening on mantle septum, rectum, and anus; posterior salivary glands medium, ca. 70% of buccal mass length; eyes large, slightly projecting.

Janet R. VOIGHT, Stephanie M. SMITH, Salome BUGLASS and Alexander ZIEGLER. 2026. A New Species of Microeledone from Galápagos Islands and an amended diagnosis of the Megaleledonidae (Octopoda: Incirrata). Zootaxa. 5814(4); 533-549. DOI: doi.org/10.11646/zootaxa.5814.4.5 [2026-05-25]

     

[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 

 x.com/TyrantLzrdQueen

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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[Cnidaria • 2026] Chironex blakangmati • Chironex box jellyfishes (Cubozoa: Chirodropida) in Singapore: New Species, and Range Extension of C. indrasaksajiae

Chironex blakangmati

Iesa, Ames, Yap & Huang, 2026 

 RAFFLES BULLETIN OF ZOOLOGY. 74

Abstract

 Two venomous box jellyfish species of the genus Chironex Southcott, 1956 (Cnidaria: Cubozoa: Chirodropida) were collected from Singapore’s coastal waters: Chironex indrasaksajiae Sucharitakul, 2017 and a novel species described herein as Chironex blakangmati, new species. Chironex indrasaksajiae was collected from both the Johor and Singapore Straits around mainland Singapore. Chironex blakangmati, new species, was collected from Sentosa Island along the Singapore Strait and is the fourth species described in the genus. While C. blakangmati’s volcano-shaped pedalial canal and tentacle number are similar to C. yamaguchii Lewis & Bentlage, 2009, its elongated, sharp-tipped velarial canals and DNA sequences distinguish it from other Chironex species. Comparisons of Chironex blakangmati, new species, with C. yamaguchii and C. fleckeri reveal novel morphological differences at the terminal end of the perradial lappet along the velarium edge, where C. blakangmati, new species, lacks velarial canals extending from the perradial lappet terminus. Juvenile Chironex yamaguchii specimens were examined and ontogenetic variations of velarial canals are herein reported. Preliminary cnidome analysis reveals eight types of nematocysts observed in C. blakangmati, new species, five types in C. indrasaksajiae, and five types in C. yamaguchii. Molecular phylogenetic reconstruction places C. blakangmati, new species, in a clade distinct from its congeners, as sister group to C. yamaguchii based on 16S rRNA gene analysis but diverging earlier than the clade comprising C. yamaguchii and C. indrasaksajiae based on cytochrome c oxidase subunit I gene analysis for which sequence data are comparatively limited. Understanding the biodiversity and seasonality of venomous cubomedusae will help mitigate the risk they pose to human health and safety during maritime activities. 

Key words. 16S rRNA, COI barcoding, marine biodiversity, phylogenetic analysis, Southeast Asia, venomous

Chironex blakangmati, new species, from Singapore.
A, live individual (paratype, ZRC.CNI.1462), lateral perradius view; B, live individual (holotype, ZRC.CNI.3014), lateral perradius view; C, cockscomb gastric saccule (sac); D, gastric cirri (gc); E, rhopalial niche front view; F, rhopalial niche side view (paratype, ZRC.CNI.1462); G, rhopalial niche side view (holotype, ZRC.CNI.3014); H, tentacle contracted with alternating brown dark bands; I, tentacle stretched; J, preserved tentacle with hollow cross section (arrow); K, pedalium with volcano pedalial canal bend (pcb) marked by arrow; L, U-shaped alternating tentacle pattern with gap marked by an arrow; M, adradial positions (ad) marked by arrows, and rhopalial niche at perradial position (per); N, gastric saccules (sac) surrounding cruciform manubrium (man); O, velarium at perradial position with frenulum (fre) arrowed, lappet terminating in simple triangular tip; P, velarium with candelabrum velarial canal pattern (holotype, ZRC.CNI.3014). rh = rhopalium, rhO = rhopalial ostium, co = convex boundary.

Chironex blakangmati, new species 

Diagnosis. Chironex with conical to cuboidal bell. Seven tentacles per pedalium, branching U-shaped alternating. Pedalial canal bend volcano shaped. Tips of velarial canals sharp towards velarial margin (Fig. 11D), with simple triangular tip at edge of velarium in perradial position (Fig. 3O & Fig. 12). Absence of velarial canals at perradial position where frenulum tapers off (Fig. 12D). 

Etymology. This species is named using Bahasa Melayu, the Austronesian language spoken in the region and the national language of Singapore, for Sentosa Island from which the animal was collected. Sentosa Island was historically referred to as “Pulau Blakang Mati”, meaning “Island of Death Behind” and, as such, “blakangmati” in denoting the geographic location is a noun in apposition. 

Iffah Iesa, Cheryl Lewis Ames, Nicholas Wei Liang Yap and Danwei Huang. 2026. Chironex box jellyfishes (Cnidaria: Cubozoa: Chirodropida) in Singapore: Chironex blakangmati, new species, and range extension of C. indrasaksajiae. RAFFLES BULLETIN OF ZOOLOGY. 74: 383–402. DOI: 10.26107/RBZ-2026-0026 [15 May 2026]

[Mollusca • 2026] Thecacera sesama • A New Species of the Genus Thecacera (Nudibranchia: Polyceridae) from Taiwan, evident from morphology and phylogenetic analyses of the 16S rDNA and cytochrome c oxidase I gene

 

Thecacera sesama Chan & Lee,

in Chan, Lee, Chen, Chang, Shao et Pang, 2026. 

 DOI: doi.org/10.3897/zookeys.1279.184298

Abstract

Thecacera sesama Chan & Lee, sp. nov. (Nudibranchia, Polyceridae) is described from north-eastern Taiwan based on an integrative taxonomic approach combining morphological and molecular data. The new species is distinguished from its congeners by a unique colour pattern consisting of a translucent white body covered with numerous small, round, black pigment spots and fewer, larger, yellow spots and five gills. While sharing a similar spotted colour pattern with Thecacera pennigera, the new species can be clearly distinguished by its significantly smaller body size (maximum length < 3 mm). Phylogenetic analyses of two mitochondrial genes, cytochrome c oxidase subunit I (COI) and 16S rRNA, confirmed it as a new species in Thecacera. The molecular data places Thecacera sesama sp. nov. as a sister species to Thecacera picta, with a significant interspecific COI divergence of 14.17%. This discovery highlights the rich, yet under documented, marine biodiversity of Taiwan and underscores the value of combining traditional morphological examination with molecular phylogenetics for accurate species delimitation in cryptic nudibranch lineages.

Key words: bryozoans, COI, cryptic diversity, Heterobranchia, phylogeny, systematics, taxonomy

Living specimens of Thecacera sesama sp. nov.
A. Ecological photos; B. ASIZM0001722; C. ASIZM0001721. Scale bars: 1 mm.

Thecacera sesama sp. nov.
Details of appearance and morphological features, hand-drawn on a tablet PC by Chen-Lu Lee. 

Thecacera sesama Chan & Lee, sp. nov.

 

Diagnosis. Thecacera sesama sp. nov. is distinguished by a unique combination of the following external morphological characters: (1) maximum preserved length of specimens is 2.83 mm; (2) body colour is translucent whitish, allowing some internal organs to be faintly visible; (3) entire body, as well as the rhinophores, rhinophoral sheaths, gills, post-branchial appendages, propodial tentacles, and tail are covered with numerous, discrete, small, circular, black spots and large yellow spots, as well as many white, snowflake-shaped pigment patches scattered on the body; (4) rhinophores and rhinophoral sheaths are translucent whitish, with small black spots and large yellow spots; (5) rhinophoral lamellae number 9–12; (6) gills number 5 and are translucent whitish, and the branchial plumes are pinnate; (7) post-branchial appendages are translucent whitish; (8) the head is translucent whitish, with short, blunt propodial tentacles at the corners.

Etymology. The specific epithet sesama is derived from the Latin word for sesame seed, referring to the characteristic small, rounded, seed-like spots that cover the dorsal surface of this species, resembling scattered sesame seeds on the animal’s body.

 Ho-Yeung Chan, Chen-Lu Lee, Wei-Cheng Chen, Chia-Hao Chang, Yi-Ta Shao and Ka-Lai Pang. 2026. Thecacera sesama sp. nov. (Nudibranchia, Polyceridae) from Taiwan, evident from morphology and phylogenetic analyses of the 16S rDNA and cytochrome c oxidase I gene. ZooKeys. 1279: 269-284. DOI: doi.org/10.3897/zookeys.1279.184298 [11 May 2026]