Range Extension Research Articles

Angle Estimation for Range-Spread Targets Based on Scatterer Energy Focusing

Wideband radar is becoming increasingly significant in modern radar systems. However, traditional monopulse angle estimation techniques are not suitable for wideband targets exhibiting range extension effects. To address this, we explore the angle estimation problem for wideband Linear Frequency-Modulated (LFM) signals and propose a new monopulse angle estimation algorithm tailored for range-spread targets. In this paper, the phase of the highest energy scatterer is used as the reference to compensate for the phases of other scatterers. The compensated scatterers are then accumulated for energy focusing. Finally, the angle of the energy-focused signal is estimated using the sum-and-difference amplitude comparison method. The proposed method can effectively focus the scatterers’ energy. Moreover, since the echo of a range-spread target can be regarded as the sum of sinusoids with different frequencies, scatterer energy focusing can effectively improve the performance of the detector. To further demonstrate the practicality of the proposed angle estimation method, it is combined with the detector to evaluate its performance. Simulation results comparing the proposed method with other approaches validate its effectiveness and demonstrate that it achieves a lower signal-to-noise ratio (SNR) threshold and higher angular accuracy. Through the proposed method, tracking and imaging can be achieved entirely within the wideband radar framework. The proposed method can also be extended to other sensor systems, advancing the development of sensor technologies.

New phylogeographic insights for the Saurodactylus brosseti species complex: range extensions and additional contact zones among evolutionary lineages

Abstract Morocco is a major biodiversity hotspot for reptiles in the Western Palearctic, yet it remains underexplored due to the remoteness and difficult access to some regions within the country. Several studies have revealed high genetic diversity and cryptic species complexes. Five evolutionary lineages of lizard-fingered geckos have been identified within the Saurodactylus brosseti species complex, later classified as separate species. In this study, we sequenced two mitochondrial markers (12S and ND4) of geckos from 14 new localities to better characterise their distribution and identify putative contact zones in the Anti-Atlas and Drâa Valley regions. Phylogeographic results extend the western range limit of S. slimanii and S. splendidus by ∼150 km and ∼110 km respectively and pinpoint two potential contact zones between these species and S. brosseti and S. harrisii. These findings will guide evolutionary studies on speciation and hybridization within this species complex.

Rediscovering Colletes bradleyi (Hymenoptera: Colletidae): First notes on natural history, male description, and a range extension

Rediscovering Colletes bradleyi (Hymenoptera: Colletidae): First notes on natural history, male description, and a range extension

Stomach Microbiome Simplification of a Coral Reef Fish at Its Novel Cold-Range Edge Under Climate Change.

Climate-driven range extensions of animals into higher latitudes are often facilitated by phenotypic plasticity. Modifications to habitat preference, behaviour and diet can increase the persistence of range-extending species in novel high-latitude ecosystems. These strategies may be influenced by changes in their gut and stomach microbial communities that are critical to host fitness and potentially adaptive plasticity. Yet, it remains unknown if the gut and stomach microbiome of range-extending species is plastic in their novel ranges to help facilitate these modifications. Here, we categorised stomach microbiome communities of a prevalent range-extending coral reef fish along a 2000-km latitudinal gradient in a global warming hotspot, extending from their tropical core range to their temperate cold range edge. At their cold range edge, the coral reef fish's stomach microbiome showed a 59% decrease in bacterial diversity and a 164% increase in the relative abundance of opportunistic bacteria (Vibrio) compared to their core range. Microbiome diversity was unaffected by fish body size, water temperature, physiology (cellular defence and damage) and habitat type (turf, barren, oyster, kelp and coral) across their range. The observed shifts in microbiome composition suggest dysbiosis and low plasticity of tropical range-extending fishes to novel environmental conditions (e.g., temperate prey and lower seawater temperature) at their novel range edges, which may increase their susceptibility to disease in temperate ecosystems. We conclude that fishes extending their ranges to higher latitudes under ocean warming can experience a simplification (i.e., reduced diversity) of their stomach microbiome, which could restrict their current rate of range extensions or establishment in temperate ecosystems.

Range Extension for Critically Endangered Sapajus xanthosternos, with Observations of Stone Tool Use at the Lower Limit of Habitat Suitability

Range Extension for Critically Endangered Sapajus xanthosternos, with Observations of Stone Tool Use at the Lower Limit of Habitat Suitability

New distributional record of the endemic Red Sea Parrotfish Scarus collana (Rüppell, 1835) from the southern coast of India

This study presents the first recorded occurrence of the endemic Red Sea parrotfish, Scarus collana (Rüppell, 1835), in Indian waters. The specimen was collected through trap fishing in the reef and paar regions of the Gulf of Mannar. The specimens were measured 10.8–34.2 cm in length (TL) and weighed 232–1248 g. This newly recorded endemic species of Red Sea represents a geographic range extension and contributes to the marine biodiversity records of India.

Complete genome analysis of the African swine fever virus genotypes II and IX responsible for the 2021 and 2023 outbreaks in Rwanda.

African swine fever (ASF) is a devastating viral hemorrhagic disease caused by the ASF virus (ASFV) that can kill up to 100% of domestic pigs and wild boars. The domestic pig industry in Rwanda is highly threatened by ASF, with several outbreaks reported yearly to the World Organization for Animal Health. Despite the endemic status, no ASFV from Rwanda has been genetically characterized. This study reports, for the first time, the ASFV genotypes causing outbreaks in Rwanda. The ASF confirmation was performed by polymerase chain reaction followed by molecular characterization of the causative ASFV by partial and complete genome sequencing and phylogenetic reconstruction. After genetic analysis, the ASFV strains responsible for the 2021 outbreak in eastern Rwanda clustered within genotype II, while the strain from the 2023 outbreak in northern Rwanda clustered within genotype IX. The extension of the geographical range of genotype II in eastern Africa is of concern. In the countries of the East African Community, this ASFV genotype was reported for the first time in Tanzania at the Tanzania-Malawi border in 2011, followed by a relentless spread of the virus northwards along major highways within Tanzania before the detection of this genotype in Rwanda in 2021. This ASFV genotype will most likely reach other eastern African countries threatening the regional domestic pig industry. The ongoing spread of ASFV genotypes II and IX across Africa impacts food and nutritional security, and hinders the realization of the United Nations Sustainable Development Goal 1 (No Poverty) and·Goal 2 (Zero hunger). The results of this study call for science-driven and regional approaches to enable the timely identification of ASF outbreaks for effective prevention and containment.

A southward range extension of the rockfish, Sebastes ventricosus (Scorpaeniformes: Scorpaenidae: Sebastinae) to Matsu Islands, Taiwan

The rockfish species, Sebastes ventricosus Temminck & Schlegel, 1843, previously documented in the southern Korean Peninsula and Japan, typically at latitudes above 32° N, is recorded for the first time in Matsu Islands, Lienchiang County, Taiwan (ca. 26° N). A detailed description of the single specimen, along with its sagittal otolith, is provided and compared with data from other specimens collected from the northwestern Pacific Ocean. This discovery marks the second record of the genus Sebastes in Taiwan’s EEZ and represents the fourth documented case of southward range extension for cold-water fishes to Taiwan. We suggest that further investigation is needed to understand the mechanism behind this southward movement, as it does not align with the typical warming trend that facilitates northward expansion.

Notes on the rare Pahang Mud Snake (Kualatahan pahangensis) (Tweedie 1946) (Squamata: Homalopsidae) endemic to Peninsular Malaysia with comments on its taxonomy and a range extension for the species

Notes on the rare Pahang Mud Snake (Kualatahan pahangensis) (Tweedie 1946) (Squamata: Homalopsidae) endemic to Peninsular Malaysia with comments on its taxonomy and a range extension for the species

Spaghetti worms from the reef: two new species of Loimia (Polychaeta: Terebellidae) from Bora-Bora and Moorea (Society Islands, French Polynesia) and a range extension of L. tuberculata Nogueira, Hutchings & Carrerette, 2015

Two new species of coral-reef inhabiting Loimia are described: L. poraporaensis sp. nov., from the lagoon at Bora-Bora, French Polynesia and Hawaii and L. aimehoensis sp. nov., from Moorea in French Polynesia. Loimia poraporaensis sp. nov. has large lateral lobes on segments 2 and 3, a smooth body and eye spots absent. Loimia aimehoensis sp. nov. has banded buccal tentacles, large lateral lobes on segments 2 and 3, with those on segment 3 extending dorsally and with a basal flange, a smooth body and eye spots absent. These species are morphologically and molecularly compared to other recently described species from Pacific coral reefs. This study also allowed us to expand the known distribution of Loimia tuberculata from the type locality at Lizard Island (northern Great Barrier Reef, Australia) Southern GBR, Western Australia, eastern Papua New Guinea and New Caledonia. We provide two maximum likelihood trees (COI and 16S genes) for all species of Loimia for which data are available, as well as an identification key and a table of the diagnostic characters for the species of Loimia of this Pacific region. We also discuss their habitat and association with living corals.

Configuration of Timepix3 read-out parameters for spectral measurements in proton therapy applications.

Configuration of Timepix3 read-out parameters for spectral measurements in proton therapy applications.

Impact of hyposalinity on the barrens-forming sea urchin Centrostephanus rodgersii in context with flooding events.

Impact of hyposalinity on the barrens-forming sea urchin Centrostephanus rodgersii in context with flooding events.

Major range extension of the genus Eucypraedia Schilder, 1939 with the discovery of a new species from the middle Miocene of South Australia

While the genus Eucypraedia Schilder, 1939 is well known in Europe, and has been reported in the Americas with the species Eucypraedia multicarinata Dall, 1890, claimed to have the widest known distribution for a Paleogene gastropod, from the Gulf of Mexico to Peru, a new species belonging to this genus has just been discovered in Southern Australia. Eucypraedia hawkei n. sp., from the Cadell Marl sediments near Adelaide, is a large species that meets all the diagnostic criteria for being assigned to this genus. Its existence therefore considerably extends the range of Eucypraedia, both geographically and temporally, since it had never before been observed in Australia or in the Miocene.

Searchin' for Urchins: Utilising Museum Collections and Citizen Science to Assess Species on the Move in the Genus Tripneustes

ABSTRACTAimWith the global redistribution of species due to warming, accurately quantifying species distributions is critical to understanding patterns in biodiversity and range shift trajectories. The genus Tripneustes comprises globally important sea urchin taxa that graze seagrass and macroalgae and have the potential to transform ecosystems. In eastern Australia, there are two Tripneustes taxa, the tropical T. g. gratilla and the subtropical‐temperate T. australiae. The temperate distribution of T. australiae was considered to be a climate‐driven range extension of T. g. gratilla until recent taxonomic clarification. We quantified the present and potential future distributions of these taxa in eastern Australia, a global warming hot spot.LocationEastern Australia and the Tasman Sea, including Lord Howe Island, Norfolk Island, and the north of New Zealand.TaxonTripneustes (Echinodermata: Echinoidea: Toxopneustidae).MethodsWe reassessed specimen identifications across four museum collections to synthesise distribution data and citizen science observations, determining the biogeographic range and realised thermal niches of Tripneustes. Habitat suitability models were used to determine current suitable habitat and predict future distributional change.ResultsWhilst T. g. gratilla has a wide tropical‐temperate distribution in the region from Papua New Guinea (9°56′2.4″ S) to Jervis Bay (35°7′12″ S) and a broad realised thermal niche (16.3°C–29.97°C), T. australiae has a subtropical‐temperate distribution (Byron Bay, 28°37′0.12″ S, to Narooma, 36°15′0″ S) and a narrower thermal niche (15.3°C–26°C). Tripneustes densities were highest in the subtropical ecoregions, where the two taxa co‐occur. Habitat suitability modelling indicated that T. australiae is a narrow‐range thermal specialist that will likely undergo a poleward range shift by 2100. In contrast, T. g. gratilla is a generalist that appears capable of occupying a broader range of conditions.Main ConclusionsDespite their similar ecological roles, congeneric Tripneustes in eastern Australia and the Tasman region have contrasting distributions and realised thermal niches, with distinct implications for their future distributions as the ocean warms.

Eleven new heteroscleromorph Demospongiae (Porifera), and a new record of the tetractinellid Ancorina corticata, from Walters Shoal, a shallow seamount on the Madagascar Ridge in the South West Indian Ocean (SWIO)

Walters Shoal is a shallow seamount located on the South Madagascar Ridge, which is situated approximately 833 km south of Madagascar and 1,296 km east of South Africa. Even though it penetrates the euphotic zone (summit is 15 m below the sea surface) and is protected by the Southern Indian Ocean Deep-Sea Fishers Association, there is a paucity of biodiversity and oceanographic data. Thus, a multidisciplinary cruise was initiated in May 2014 on the FRS Algoa as a component of the African Coelacanth Ecosystem Programme (III). This paper reports on 11 new heteroscleromorph Demospongiae collected from Walters Shoal, namely Chelotropella alexrogersi sp. nov., Penares waltershoalensis sp. nov., Tethya muricyi sp. nov., Agelas kellyae sp. nov., Ptilocaulis ramosus sp. nov., Halichondria (Halichondria) madagascarensis sp. nov., Aaptos incrustans sp. nov., Lissodendoryx (Lissodendoryx) ingolei sp. nov., Fibulia punicea sp. nov., Clathria (Clathria) flo sp. nov. and Callyspongia (Callyspongia) cacumen sp. nov. Additionally, a range extension of Ancorina corticata Lévi, 1964, is reported. The sponge assemblage had high levels of endemism with several species shared by both the western and eastern flanks of the seamount. In contrast, sponge assemblages differed significantly according to depth, with the mesophotic zone (31–150 m) acting as a transition between the shallow (15–30 m) and submesophotic (> 150 m) zones. Species richness and the number of new species were highest in the submesophotic zone.

An eastern Congolian endemic, or widespread but secretive? New data on the recently described Afrixaluslacustris (Anura, Hyperoliidae) from the Democratic Republic of the Congo.

The Great Lakes spiny reed frog (Afrixaluslacustris) was recently described from transitional (submontane) forests at mid-elevations of the Albertine Rift mountains in the eastern Congolian region. Previously, because of its similarity, it had been understood to represent eastern populations of the unrelated A.laevis, which is known mainly from Cameroon. Based on DNA barcoding, we document the westward extension of the known range of A.lacustris within lowland rainforests in the Northeastern and Central Congolian Lowland Forests. One sample was represented by a larva found in a clutch in a folded leaf, a typical oviposition type for most Afrixalus species, contrary to oviposition on an unfolded leaf surface in the similar A.laevis and closely related A.dorsimaculatus and A.uluguruensis. Comparison of the advertisement call of A.lacustris from Salonga National Park, Democratic Republic of the Congo, indicates similarity to its sister species from montane areas of the Albertine Rift, the ghost spiny reed frog (A.phantasma). Phylogeographic analysis suggests that A.phantasma and A.lacustris speciated allopatrically during the Early Pleistocene, with the former having refugia in montane forests and the latter in transitional and also lowland forests. The lowland populations of A.lacustris represent distinct evolutionary lineages, which diversified probably in isolated forest refugia during the Middle Pleistocene.

Range Extension of Borehole Strainmeters Using MOSFET-Based Multi-Switch Automatic Zero Setting.

Borehole strainmeters are essential tools for observing crustal deformation. In long-term observational applications, the dynamic changes in crustal deformation over multi-year scales often exceed the single measurement range of borehole strainmeters. Expanding the measurement range while maintaining high precision is a critical technical challenge. To address this, a full-range measurement system was developed using a bidirectional analog multi-switch based on MOS transistors and automatic feedback control. This system automatically adjusts the zero point of the measurement bridge, maintaining the bridge output at a near-balanced state. The quantifiable zero-setting actions are dynamically converted into equivalent voltage, enabling automatic full-range measurements while fully utilizing the effective linear range of the differential capacitive sensors. A laboratory performance tests demonstrated that an RZB borehole strainmeter equipped with this automatic zero-setting range extension system successfully covers the differential capacitive sensor's effective linear range of approximately 100 μm.

Hook, line, and social media: crowd-sourced images reveal size and species patterns of ocean sunfishes (Tetraodontiformes, Molidae) from California to Alaska

Taxonomic confusion and limited data have impeded species-level biogeographic analyses of the world’s largest bony fishes, ocean sunfishes (Molidae; ‘molids’), in many ecosystems. However, recent advances in molid taxonomy and the emergence of photo-based community-science platforms provide an opportunity to revisit species-level biogeography. In this study, we use crowd-sourced images of 1,213 ocean sunfishes to determine if molid morphology visible in citizen-science images permits reliable species determination. From the ensuing data, we describe patterns in molid size structure and species composition from 1,178 molids observed in the Alaska and California Current Systems (ACS and CCS, respectively). Molids <1 m total length (TL) were commonly reported in the CCS, particularly off the central coast of California, suggesting this area may function as a molid nursery. Molids >1 m TL were more commonly observed in both the CCS and cooler ACS, which suggests larger molids occupy a larger thermal range (ontogenetic habitat expansion) than smaller individuals. Overall, Mola mola was the most frequently observed species in both the ACS and CCS; however, the persistent occurrence of Mola tecta in both current systems suggests a range extension for this otherwise Southern Hemisphere species. The species identity of six M. tecta specimens from California and Alaska were verified with genetic analysis. Finally, two Mola alexandrini confirmed in the southern portion of the CCS represent the first records of this species in the Northeast Pacific Ocean.

Hibiscus sidiformis Baill. (Magnoliopsida: Malvales: Malvaceae): A New Addition to the Flora of India

ABSTRACTIn the present communication, Hibiscus sidiformis Baill. is reported as a new record for India from the arid region of Kachchh district, Gujarat state. The newly reported species shows a close similarity with the resembling resident species Hibiscus lobatus (Murray) Kuntze. A detailed taxonomic description with the palynological comparison is provided for the first time. The extension in the native range of H. sidiformis from Africa to Asia is proposed.

Can citizen science fill knowledge gaps for the world’s most speciose and poorly-known insular amphibian fauna?

Context Tropical regions host the richest, yet most poorly known and threatened concentrations of biodiversity on the planet. Citizen science is increasingly viewed as a strategy to help fill these key data gaps. However, inadequate taxonomic frameworks, social inequities, and poor infrastructure may all constrain this potential. Aims To examine how effectively citizen science data from iNaturalist fills gaps in knowledge about the distribution, species richness and conservation status of a megadiverse tropical biota, namely the frogs of Melanesia (New Guinea and nearby islands). Methods We identified all records of Melanesian frogs on iNaturalist to species or genus where possible. Species distributions on iNaturalist were then compared to existing distribution maps and records to identify range extensions, and the IUCN Red List conservation status of any species not currently considered Least Concern was assessed based on new distributional information. Key results We estimate that around 125 described Melanesian frog species (23% of the total fauna) have been recorded on iNaturalist, including putative range extensions for at least 42 species. Based on these new data we recommend updating IUCN Red List assessments for nearly 20 previously Not Evaluated, Data Deficient, or Vulnerable species. Many records cannot be identified to species, and this issue is compounded by a mismatch between the area best-known scientifically (Papua New Guinea) and the area from which the majority of citizen science records originate (Indonesia). Conclusions Citizen science has clear potential to fill some key knowledge gaps for poorly-known tropical biotas, but does not obviate the need for baseline survey and taxonomic work based on voucher specimens with associated tissues. Implications Based on our experience, we make recommendations that may increase the impact of citizen science data for poorly-known biotas.