The Northern Solstice.

The Northern) Solstice falls on Thursday 20 June this year (2024), the day on which the Sun rises highest in the sky and the longest day of the year in the Northern Hemisphere (where it is the Summer Solstice) and the day on which the Sun rises lowest in the sky and the shortest day in the Southern Hemisphere (where it is the Winter Solstice). Up until this date the days have been growing shorter in the Northern Hemisphere and longer in the Southern Hemisphere since the Southern Solstice in December last year (which is the Summer Solstice in the Northern Hemisphere and Winter Solstice in the Southern Hemisphere), but after it the situation will be reversed, with days growing steadily longer in the Northern Hemisphere and shorter in the Southern Hemisphere until the next Southern Solstice in December. 

The solstices are entirely a product of variation in the Earth's rotation on its axis, which is at an angle of 23.5° to the plain of the Earth's orbit about the Sun. This means that in December the Earth's Southern Pole is tilted towards the Sun, while the Northern Pole is tilted away from it. This means that around the Southern Solstice the Southern Hemisphere is receiving radiation from the Sun over a longer part of the than the Northern, and at a steeper angle (so that it to pass through less atmosphere to reach the planet), creating the southern summer and northern winter.

The tilt of the Earth at the Northern Solstice. Wikimedia Commons.

The solstices are fairly noticeable astronomical events, and tied to the seasons which govern the life cycles of life on Earth, and they have been celebrated under different names by cultures across the globe, but most notably by those at higher latitudes, who are more profoundly affected by the changes of the seasons.

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Oroperipatus tiputini: A new species of Velvet Worm from the Ecuadorian Amazon.

Velvet Worms, Onychophora, are a unique group of elongate, soft bodied, many legged  Animals, given phylum status and considered to be among the closest living relatives to the Arthropods. They are currently the only known phylum of Animals known entirely from terrestrial species, both living and fossil, although they may be related to the Lobopodans, an entirely marine group known only from Early Palaeozoic fossils. 

The 230 living Velvet Worm species are divided into two groups, the Peripatidae, found in the tropics of Central and South America, the Antilles Islands, Gabon, India, and Southeast Asia, and the Peripatopsidae, found in Chile, South Africa, Papua New Guinea, Australia, and New Zealand. All South American members of the Peripatidae are placed within a single clade, the Neopatida, which is further divided into two lineages, the 'Andean' genus Oroperipatus, and the 'Caribbean' lineage, comprising all other genera.

In a paper published in the journal Zoosystematics and Evolution on  14 June 2024, Jorge Montalvo-Salazar of  the Instituto de Biodiversidad Tropical at the Universidad San Francisco de Quito, and the Laboratorio de Zoología Terrestre at the Quito Museo de Zoología, Lorena Bejarano and Alfredo Valarezo of the Instituto de Energía y Materiales at the Universidad San Francisco de Quito, and Diego Cisneros-Heredia, also of the Instituto de Biodiversidad Tropical at the Universidad San Francisco de Quito, and the Laboratorio de Zoología Terrestre at the Quito Museo de Zoología, and of the Estación de Biodiversidad Tiputini of the Universidad San Francisco de Quito, and the Ecuadorian Instituto Nacional de Biodiversidad, describe a new species of Oroperipatus from the Amazonian lowlands of Ecuador.

The new species is described from five male, three female, and three juvenile specimens collected in the vacinity of the Tiputini Biodiversity Station of the Universidad San Francisco de Quito in Orellana Province, Ecuador, between 2001 and 2023, as  well as one youngling, which one of the female specimens gave birth to in captivity. The new species is named Oroperipatus tiputini, in reference to the location where it was discovered. 

Oroperipatus tiputini, adult female holotype (ZSFQ-i8248) and youngling paratype (ZSFQ-17794) a few days after being born. Pedro Peñaherrera in Montalvo-Salazar et al. (2024).

Adult female specimens of Oroperipatus tiputini very between 46 and 65.3 mm in length, while the adult males are smaller at 22.7 to 39.8 mm. Females have between 37 and 40 pairs of legs, while the males have between 34 and 37, although one male specimen had a different number of legs on each side, with 35 legs on the right and 36 legs on the left. The species shows considable colour variation, with one adult male being a light brown colour with a faint rhomboid pattern, two adult males and one adult female being brown with orange diamonds, and another female (the one which produced a youngling) being a plain dark orange colour. The youngling itself was yellowish with a diamond pattern. All specimens were darked on their heads and antenae,  had orange or brown legs, and a distinctive white band on the head.

Oroperipatus tiputini, adult male paratype, ZSFQ-i8270. Pedro Peñaherrera in Montalvo-Salazar et al. (2024).

Most specimens of Oroperipatus tiputini were found on small herbaceous Plants within old growth, closed canopy upland forests around the Tiputini Biodiversity Station. Other specimens were found in leaf litter, or on the butress roots of trees to a height of about 70 cm above the ground. One specimen was found in a Bromiliad. The Worms were more active at night. 

Oroperipatus tiputini, adult male paratype, ZSFQ-i5151. Diego Cisneros-Heredia in Montalvo-Salazar et al. (2024).

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Archeologists uncover mysterious Minoan structure on the Greek island of Crete.

Archaeologists on the Greek island of Crete carrying out survey work ahead of the construction of a new airport have uncovered a mysterious structure believed to date from the Late Palaeopalatial Period of the ancient Minoan civilization, according to a press release issued by the Greek Ministry of Culture on 11 June 2024.  The excavation work was being carried out on Papoura Hill on the eastern part of the island, where it was planned to build radar station to serve the new airport, though the significance of the discovery means that serious consideration is now being given as to whether this part of the project can go ahead as planned.

The new monumental structure discovered on Papoura Hill, Crete. Greek Ministry of Education.

The structure is believed to have been constructed between about 2000 and 1700 BC, and to have remained in use for several hundred years. It comprises a series of stone rings, which are on average 1.4 m thick, and rise a maximum of 1.7 m above the surroundings. The outer diameter of this structure is about 48 m, with what appears to have been a circular building 15 m in diameter at the centre. This building had entrances on the northwest and southwest parts of its diameter. The area surrounding the structure has produced thousands of Animal bones, suggesting that the site was used for ritual feasting.

The new Minoan structure seen from above. Greek Ministry of Culture.

No similar structure has been found at any Minoan site, despite many decades of intensive study of the culture, emphasising the uniqueness of the site. Possible similarities to structures at the Mycenaean site of Tiryns in the Peloponnese, or the elliptical Middle Minoan house at Hamezion on eastern Crete, although investigations at the site are still at an early stage.

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A new specimen of the Hupehsuchian Nanchangosaurus throws light on the origin of the earliest Mesozoic Marine Reptiles.

The first groups of Mesozoic Marine Reptiles returned to the seas early in the Triassic, quickly gaining suites of specialist adaptations to pelagic life which have made it hard to determine their closest terrestrial relatives. The most notable of these groups is the Ichthyopterygia (Ichthyosaurs and close relatives), a group which for a long time were considered to be of uncertain affinities, and which today are placed within the Diapsida, but with no widely accepted hypothesis on their relationship to other members of this group. The sister group to the Ichthyopterygia is considered to be the Omphalosauridae, another group of highly modified pelagic Marine Reptiles, with the two groups forming the Ichthyosauriformes.

The Hupehsuchians are a group of small Mesozoic Marine Reptiles known only from the Early Triassic deposits of the Nanzhang-Yuan’an region of Hubei Province, South China. As with other Marine Reptile groups, their affinities were for a long time hard to determine, though in the last decade it has been realised that they are the sister group to the Ichthyosauriforms, with the two groups together being referred to as the Ichthyosauromorphs. Hupehsuchians had elongate bodies with slender heads, dermal plates on their dorsal surfaces, dense ribs and tightly packed gastralia. Importantly, they were fairly small, ranging from 40 cm to about 2.3 m in length, and restricted to shallow-marine environments, suggesting that they may be closer to the terrestrial origins of the Ichthyosauromorphs than other members of the group.

A large number of Hupehsuchian specimens have been found, and the anatomy of the group reasonably well understood. However, almost all of these specimens are preserved in lateral view, with only three specimens known with their skulls preserved in ventral view, which presents challenges when comparing Hupehsuchians to other groups

In a paper published in the journal Historical Biology on 25 May 2024, Jun Liu, Fan Wu, and Yu Qiao of the Division of Geology at Hefei University of Technology describe a new Hupehsuchian specimen from the Early Triassic Jialingjiang Formation in Yuan’an County, in the west of Hubei Province, China, which is preserved in ventral view, and discuss the implications of this for our understanding of the origins of the Hupehsuchians and related groups.

The specimen, HFUT YAV-10-001, is a small, well-preserved Hupehsuchian on a slab and counter-slab in ventral view, and held in the collection of the Geological Museum of Hefei University of Technology. This comprises the skull, a set of 36 articulated vertebrae and associated ribs, and a partial appendicular skeleton, including both pectoral girdle, forelimbs and partial hindlimbs. The majority of the bones are preserved on the main slab, while vertebral and rib fragments and the right pectoral girdle and forelimb elements are preserved on the counter slab. 

The Hupehsuchian HFUT YAV-10-001 from the Early Triassic of Hubei Province, South China. (A) Photograph of the skeleton on the main slab. (B) Photograph of the skeleton on the counter slab. (C) Interpretive drawing of the skeleton on the main slab. (D) Interpretive drawing of the skeleton on the counter slab. Scale bars are 1 cm. Abbreviations: 2 and 4, distal carpals; I, IV and V, metacarpals; ax, axis; axr, axis rib; bo, basioccipital; Cl, clavicle; cna#, cervical neural arch; Co, coracoid; da, dermal armour; dna#, dorsal neural arch; dns#, dorsal neural spine; dnss, dorsal neural spine second (distal) segment; dr#, dorsal rib; F, femur; Fi, fibula; H, humerus; i, intermedium; mand, mandibular ramus; pm, premaxilla; R, radius; r, radiale; Sc, scapula; Ti, tibia; U, ulna; u, ulnare. Jun et al. (2024).

Jun et al. consider HFUT YAV-10-001 to be referable to the genus Nanchangosaurus, having the same number of cervical vertebrae, as well as distinctively low neural spines, as well as lacking a parapophysis, and having subequally-sized scapula and coracoid bones. However, it differs from the previously described Nanchangosaurus suni in a number of features, including having forelimbs which are longer compared to the size of the Animal, and a smaller overall size, with Nanchangosaurus suni reaching about 20 cm in length, while HFUT YAV-10-001, which is clearly an adult, has an estimated size of only 15 cm. This could be a sign that HFUT YAV-10-001 represents a new species of Nanchangosaurus, but it may also indicate that Nanchangosaurus suni was sexually dimorphic, something which has been suggested in early Ichthyosauriforms and Sauropterygians, and which might therefore be predicted in an early Hupehsuchian. For this reason, Jun et al. assign specimen HFUT YAV-10-001 to Nanchangosaurus cf. suni.

The different aspect in which HFUT YAV-10-001 enables significant extra features to be added to a matrix used for the phylogenetic analysis of Diapsidans. Jun et al. recover HFUT YAV-10-001 as a Hupehsuchian, and the Hupehsuchians as the sister group to the Ichthyosauriformes, together  forming the Ichthyosauromorphs, as with previous studies. Their analysis further suggests that the Ichthyosauromorphs form the sister to the Sauropterygomorpha (a diverse group of Mesozoic Marine Reptiles which included groups such as the Nothosaurs and Plesiosaurs), and that this larger grouping forms a sister group to the Thallatosauria, a group of Lizard-like Marine and semi-Marine Reptiles, again restricted to the Triassic.  This grouping of the Ichthyosauromorphs, Sauropterygomorphs, and Thalattosaurs was in turn found to be the sister group to the Archosauromorphs, the group that includes the Archosaurs (Pterosaurs, Crocodilians, and Dinosaurs) plus close outgroups such as the Rhynchosaurs and Tanystrophids.

Simplified phylogeny of Sauria showing the relationships of Ichthyosauromorphs to other Reptiles. Jun et al. (2024).

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Eruption and lahar on Mount Kanloan, Negros Island, the Philippines.

Mount Kanlaon, a 2465 m stratovolcano (cone shaped volcano made up of layers of ash and lava) on northern Negros Island in the central Philippines, erupted on Monday 3 June 2024, producing a 5km high column of ash, and subsequent ashfalls in the area around the volcano. On Wednesday 5 June heavy rainfalls in the area produced a series of lahars (mudslides of volcanic ash) which swept down watercourses in some cases entering villages. There are no reports of any casualties, but the Philippine Institute of Volcanology and Seismology has warned that the mud is likely to be toxic, raising concerns about the availability of safe water in the effected villages.

An eruption on Mount Kanloan, Negros Island, the Philippines on Monday 3 June 2024. Dollet Demaflies/AFP/Getty Images.

The geology of the Philippines is complex, with the majority of the islands located on the east of the Sunda Plate. To the east of this lies the Philippine Sea plate, which is being subducted beneath the Sunda Plate (a breakaway part of the Eurasian Plate); further east, in the Mariana Islands, the Pacific Plate is being subducted beneath the Philippine Sea Plate. This is not a smooth process, and the rocks of the tectonic plates frequently stick together before eventually being broken apart by the rising pressure, leading to Earthquakes in the process. Material from the subducting Philippine Plate is heated by the temperature of the Earth's interior, causing lighter minerals to melt and the resultant magma to rise through the overlying Sunda Plate, fuelling the volcanoes of the Philippines.

Subduction beneath the Philippines. Yves Descatoire/Singapore Earth Observatory.

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