Lacustrine sediments of the Lower Cretaceous (lower Aptian) Xiagou Formation exposed near the village of Changma in the Changma Basin of northwestern Gansu Province, China have yielded more than 100 avian partial skeletons, many of which also preserve remnants of soft tissues such as feathers and skin. Collectively, these fossils characterize a rich avifauna dominated by the crownward ornithuromorph Gansus yumenensis Hou and Liu, 1984. Despite this wealth of Early Cretaceous bird material, no skeletal remains of other dinosaurs have been described from Changma to date. Here we report the first non-avian dinosaur body fossil from the Xiagou Formation of the Changma Basin. Consisting of an articulated left pectoral girdle and forelimb lacking the carpus and manus, the specimen pertains to a new dromaeosaurid theropod taxon, Jian changmaensis, gen. et sp. nov. Phylogenetic analysis recovers Jian within Microraptorinae, expanding the definitive fossil record of this clade to include northwestern China. The new Changma microraptorine constitutes an additional similarity between the theropod faunas of the Xiagou Formation of the Changma Basin and penecontemporaneous strata of the Jehol Group of northeastern China. In particular, the Changma theropod assemblage closely resembles that of the Sihedang locality of the Jehol Group in that both include representatives of Microraptorinae and are overwhelmingly dominated by single ornithuromorph taxa that phylogenetic analyses have repeatedly resolved as close relatives. This raises the possibility that the two sites were deposited under comparable paleoenvironmental settings that are otherwise poorly represented at known Jehol localities. 

Key Words: Early Cretaceous, Gansus yumenensis, Jian changmaensis, microraptorine, paleobiogeography, paleoenvironment, phylogeny, Sihedang.

Dinosauria Owen, 1842 

Saurischia Seeley, 1888 

Theropoda Marsh, 1881 

Maniraptora Gauthier, 1986 

Dromaeosauridae Matthew and Brown, 1922 

Microraptorinae Xu, 2002 

Diagnosis.—Medium-sized (intermediate in skeletal dimensions between adult specimens of Microraptor zhaoianus and Sinornithosaurus millenii Xu et al., 1999; see Table 2) microraptorine dromaeosaurid theropod characterized by the following three autapomorphies: (1) a coracoid that is proportionally longer relative to the humerus than in any other microraptorine (~36% humerus length; the next closest individuals are the immature Microraptor IVPP V31612, with a value of ~35%, and IVPP V12811, the holotype of Sinornithosaurus, with a value of 33%) (Table 2); (2) humeral distal condyles developed on the cranial surface of this bone (Figs. 2B–C, 3E; a local autapomorphy within Microraptorinae, shared with nonmicroraptorine theropods such as the therizinosaur Erlikosaurus andrewsi Barsbold and Perle, 1980, and Aves); and (3) a well-developed foramen on the ventral aspect of ...

Etymology.—The genus name is for the Jiān (鹣), a one winged bird in Chinese mythology, in reference to the bird-like, possibly volant nature of this microraptorine taxon and the skeletal composition of its holotype (an isolated partial pectoral girdle and forelimb). The specific name is for Changma (昌马), the locality where the holotype was discovered.

Gentiana macneilliana A.K.Halder & D.Maity, sp. nov.

Gentiana macneilliana is morphologically most similar to Gentiana lacinulata but differs from that species by its short petiole, 0.5–1.5 mm long (vs up to 3 mm); acute and usually mucronate leaf apex (vs obtuse leaf apex); narrowly revolute leaf margin (vs flat leaf margin); longer pedicel, up to 8 mm long (vs up to 3 mm long); ovate corolla lobes with acuminate apex (vs suborbicular with obtuse-rounded or rounded apex); much longer plicae, 1.5–2.6 mm long (vs 0.7–1 mm); and plicae more than 1/2 as long as corolla lobes (vs less than 1/3 as long as corolla lobes). It also resembles Gentiana muscicola but can be differentiated from that species by its unique ovate, acuminate corolla lobes with erose margin and distinctly contracted base (vs ovate–lanceolate or ovate–triangular, obtuse or subacute lobes with entire margin and widened base); short petiole, 0.5–1.5 mm long (vs up to 2.5 mm); narrowed leaf bases (vs rounded to cordate leaf bases); long pedicel, up to 8 mm (vs up to 3.1 mm); and short style, 1.5–1.9 mm (vs 3–4 mm). 

Etymology. The specific epithet ‘macneilliana’ is given in honour of Dr John McNeill, Royal Botanic Garden Edinburgh (E), the legendary taxonomist and nomenclature specialist, who has given immense support with the nomenclature of Indian Gentiana.

HELEN H. HAIBIL, OLGA MACAS NUÑEZA, DAYANG FAZRINAH BINTI AWG DAMIT, RAZY JAPIR, ARTHUR Y.C. CHUNG and MING KAI TAN. 2026. New Species and Bioacoustics of Varitrella (Cantotrella) (Oecanthidae: Podoscirtinae) from Sulu Archipelago and Borneo’s Sabah.  Zootaxa. 5821(1); 61-77. DOI: doi.org/10.11646/zootaxa.5821.1.4 [2026-05-28]

 

 A new species of semiterrestrial crab, Geosesarma penrissen, new species, is described herein from Mount Penrissen in southwestern Sarawak, Malaysia. It represents the third species of Geosesarma known from the montane forests of Borneo, the other two being G. larsi Ng & Grinang, 2018 from Mount Ampungan in Serian, Sarawak, and G. aurantium Ng, 1995 from Mount Silam in Sabah. Diagnostic characters distinguishing G. penrissen, new species, from its congeners are provided, together with ecological notes on its highland habitat. 

Key words. freshwater crab, semiterrestrial, taxonomy, lowland forest, comparative morphology

Diagnosis. Carapace almost square, width-to-length ratio 1.01–1.07, lateral margins gently sinuous, subparallel (Figs. 1A, D, 2A–D, 5A, C, F, 6A, D); dorsal surface with welldefined regions, anterior regions covered with small, rounded or flattened, squamate granules (Figs. 1A, C, E, F, 2A–D, 5A, C, E, 6A, D); front deflexed, with 2 broad subtruncate lobes, separated by shallow median concavity; postfrontal, protogastric lobe prominent, sharp-edged (Figs. 1A, C, D, 2A–D, 3A, 6C, F); external orbital tooth acutely triangular, outer margins curving anteriorly, tooth directed obliquely and laterally, clearly extending beyond lateral margin of carapace (Figs. 2A–D, 5A, C, E, 6A, D). Merus of third maxilliped ...