Ctenomys uco: A new species of Tuco-tuco from Mendoza Province, Argentina.

Tuco-tucos, Ctenomys spp., are a large group of burrowing Rodents found in South America from southern Peru to the southern tips of Chile and Argentina. There are currently 68 living members of the genus, eleven of which have beed described in the last decade, during which time the application of genetic analysis to phylogenetic studies has led to the genus being divided into eight well-supported species groups, as well as several other groups with less clear relationships. The Ctenomys mendocinus species group has been the subject of several recent studies, which have led to several new species being erected, as well as a number of previously described species having been recognised as populations of other species, and several lineages identified which appear to be as yet undescribed species. One such population is found in northwestern Mendoza Province, Argentina, with populations at Tupungato and the Valley of Arenales which were previously thought to belong to the species Ctenomys mendocinus having been identified as genetically distinct, although the morphological distinctness of these Tuco-tucos has not been assessed.

In a paper published in the journal Vertebrate Zoology on 8 March 2024, Raquel Alvarado-Larios of the Laboratorio de Filogeografía at the Instituto Argentino de Investigaciones de las Zonas Áridas, Pablo Teta of the División Mastozoología at the Museo Argentino de Ciencias Naturales 'Bernardino Rivadavia', Pablo Cuello, also of the Laboratorio de Filogeografía at the Instituto Argentino de Investigaciones de las Zonas Áridas, Pablo Jayat of the Unidad Ejecutora Lillo and the Departamento de Ciencias Básicas y Tecnológicasat the Universidad Nacional de Chilecito, Andrea Tarquino-Carbonell, again of the Laboratorio de Filogeografía at the Instituto Argentino de Investigaciones de las Zonas Áridas, Guillermo D’Elía of the Instituto de Ciencias Ambientales y Evolutivas and the Colección de Mamíferos at the Universidad Austral de Chile, and Paula Cornejo and Agustina Ojeda, again of the Laboratorio de Filogeografía at the Instituto Argentino de Investigaciones de las Zonas Áridas, formally describe the Mendoza Tuco-tuco as a new species, based upon genetic and morphological data.

The new species is named Ctenomys uco, in reference to the Valle de Uco, the region in which the new species was discovered. It is a small Tuco-tuco, reaching 215-263 mm in length, with a drab or dusky drab coat, lighter on the flanks and underside, with the underside sometimes also having a brownish tinge. 

External appearance of Ctenomys uco. (A) CMI 7712 (holotype), from Cajón de Arenales, Tunuyán, Mendoza, Argentina; (B) CMI 7737, from Finca Caicayén II, Tupungato, Mendoza, Argentina. Alvarado-Larios et al. (2024).

While the populations assigned to Ctenomys uco were formerly assigned to Ctenomys mendocinus, but a genetic study based upon the mitochondrial cytochrome b gene found that not just were these populations distinct from Ctenomys mendocinus, but also that they aren't particularly closely related, with Ctenomys uco instead forming a sister species to Ctenomys fochi, and these two together forming the sister taxon to a clade which includes Ctenomys verzi, Ctenomys mendocinus, and Ctenomys flamarioni, as well as two as yet un-named lineages.

Ctenomys uco is known from only two locations, 39 km appart, but Tuco-tucos have been reported elsewhere in the region, which are likely to belong to the same species, for which reason Alvarado-Larios et al. decline to make a detailed assessment of the species distribution or conservation status at this time. The species seems to be solitary in nature, and lives in an environment between the Low Monte and the Southern Andean Steppe at altitudes of 1000 and 2710 m above sealevel. One of the known populations lives largely within vineyards, digging burrows at the foot of vines.

Views of the landscapes at the two known localities of Ctenomys uco. (A )Mendoza, Tunuyán, Cajón de Arenales (type locality), (B) Mendoza, Tupungato, vineyards of Finca Caicayén II (note the burrows at the lower right corner on this photograph). Alvarado-Larios et al. (2024).

The region is close to the Andes, and has a temperate climate with harsh winters, hot summers with cool nights. The mean annual temperature varies between about 10°C and about 15°C, with an average of about 300 mm of rain each year, most of which falls in winter.

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Promyrmekiaphila korematsui: A new species of Trapdoor Spider from California.

Cryptic species are species which resemble one-another physically yet are reproductively isolated from each other. While such species clusters can come about due to convergent evolution, the vast majority are closely related species which have become reproductively isolated, but which have not diverged morphologically, usually as a result of a physical barrier splitting a population, followed by genetic drift. This is particularly common among morphologically conservative groups with low distribution rates, such as Mygalomorphs (Tarantulas, Trapdoor Spiders etc.), which are large Spiders occupying silk-lined burrows, typically remaining at a single site for their entire lives. 

In a paper published in the journal Ecology and Evolution on 1 March 2024, James Starrett, Emma Jochim, Iris Quayle, Xavier Zahnle, and Jason Bond of the University of California, Davis, present the results of a genetic study of the Trapdoor Spider genus Promyrmekiaphila, which is known only from California, and describe a new species, the third within the genus.

The genus Promyrmekiaphila was first described in 1950 by the Swiss arachnologist and herpetologist Ehrenfried Schenkel to describe a morphotype of Trapdoor Spider found across California, which he named Promyrmekiaphila gertschi. This was later found to have previously been described by the French naturalist Eugène Simon as Aptostichus clathratus in 1891, though it was later recognised that the assignation of the species to the genus Aptostichus was wrong, and Schenkel's name Promyrmekiaphila was adopted, leading to the combination Promyrmekiaphila clathratus.

In 2007 and 2008 Amy Stockman and Jason Bond, then both at the Department of Biology at East Carolina University, carried out a study of the population of Promyrmekiaphila clathratus using mitochondrial DNA (mtDNA), coming to the conclusion that there were in fact two species within the genus, Promyrmekiaphila clathratus found throughout the coastal ranges in central and northern California, and a new species, which they named Promyrmekiaphila winnemem, which was found at the northern end of the Central Valley. 

However, Stockman and Bond recognised that a study based upon mtDNA alone had its limitations, and that there still remained the possibility of other, cryptic, species of Promyrmekiaphila being found in California. 

Starrett et al.'s new study is based upon a wider gene set. This identified a number of deeply separated lineages within the Promyrmekiaphila clathratus  population, although Starrett et al. decline to name these as new species at this time, reasoning that they are not yet sufficiently genetically different to be reproductively isolated. However, a small group of Spiders found close to the San Andreas Fault line, from mid-San Francisco Peninsula to the Diablo Range, east of Paicines, were found to comprise a sister group to the Promyrmekiaphila clathratus and Promyrmekiaphila winnemem pair, therefore clearly representing a new species.

This new species is named Promyrmekiaphila korematsui, in honour of Fred Toyosaburo Korematsu, who  was awarded the United States Presidential Medal of Freedom in 1998 in recognition of his lifelong dedication as a civil rights activist and his resistance to the  incarceration of Japanese Americans in concentration camps during World War II.

Promyrmekiaphila korematsui, male live habitus photographs, side and dorsal views. Starrett et al. (2024).

Promyrmekiaphila korematsui is found d in shaded ravines and along roadcuts in Oak woodland habitat. Its distribution overlaps with that of Promyrmekiaphila clathratus, which may have implications for evolution of the genus, although the small sample size available for the genus so far prevents any detailed  analysis at this time.

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Trimeresurus ayeyarwadyensis: A new species of Mangrove Pit Viper from the Ayeyarwady and Yangon regions in Myanmar.

The taxonomy of the Asian Pit Viper genus Trimeresurus have proved difficult to unravel, as species tend to be both similar to one-another and morphologically variable. The Mangrove Pit Vipers, Trimeresurus purpureomaculatus and Trimeresurus erythrurus are considered to form a species complex, with Trimeresurus purpureomaculatus being an obligate Mangrove-inhabitant with variable colouration and dark blotches on its back, found in southern Thailand, Peninsula Malaysia, and on the island of Sumatra, while Trimeresurus erythrurus is a green Snake lacking markings, found in but not restricted to Mangroves, found in northern Myanmar, and eastern Bangladesh and India. Between these, in southern Myanmar, is a population of Snakes which show a mixture of traits seen in the other two groups, which have been assumed to represent a zone of hybridization. However, a recent study of genetic structures within the group has suggested that this southern Myanmar population is actually a separate species, which forms a sister taxon to Trimeresurus purpureomaculatus, although this species does show signs of hybridizing with Trimeresurus erythrurus.

In a paper published in the journal ZooKeys on 13 December 2023, Kin Onn Chan of the Lee Kong Chian Natural History Museum at the National University of Singapore, and the School of Biological Sciences at the Universiti Sains Malaysia, Shahrul Anuar, also of the School of Biological Sciences at the Universiti Sains Malaysia, Ananthanarayanan Sankar of the Herpetological Society of Singapore, and the Department of Biological Sciences at the National University of Singapore, Ingg Thong Law and Ing Sind Law, also of the Herpetological Society of Singapore, Rasu Shivaram, also of the Lee Kong Chian Natural History Museum at the National University of Singapore, and of the Herpetological Society of Singapore, Ching Christian, again of the Herpetological Society of Singapore, and of the Department of Life Sciences at the Natural History Museum, Daniel Mulcahy of the Museum für Naturkunde at the Leibniz Institute for Evolution and Biodiversity Science, and Anita Malhotra of the School of Natural Sciences at Bangor University, formally describe the southern Myanmar Trimeresurus population as a new species. 

The new species is named Trimeresurus ayeyarwadyensis, meaning 'from Ayeyarwady'; the species is known from the Ayeyarwady and Yangon regions on the Ayeyarwady delta in southern Myanmar. The species has partially fused first infralabial and nasal scales, a condition not seen in any other member of the genus Trimeresurus, but otherwise shows a mosaic of traits seen in other species.

An unvouchered, live specimen of Trimeresurus ayeyarwadyensis from the Yangon Region, Myanmar. Wolfgang Wüster in Chan et al. (2023).

Unhybridized populations of Trimeresurus ayeyarwadyensis were found in Mangrove forests in the Pyapon and Myaungmya districts of the Ayeyarwady Region, as well as in a forest surrounding a lake unconnected to any Mangrove system in the Hlawga Park in the Yangon Region. In the Pathein District of the Ayeyarwady Region a population of Trimeresurus ayeyarwadyensis hybridized with Trimeresurus erythrurus was found living alongside an unhybridized population of Trimeresurus erythrurus. Trimeresurus purpureomaculatus is known from the Dawei District in the Tanintharyi Region of Myanmar, and could potentially have a contact zone with Trimeresurus ayeyarwadyensis in Mon State, where no members of the genus Trimeresurus have been recorded, but this is thought likely to be due to a lack of searching rather than an absence of Snakes.

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Planigale kendricki & Planigale tealei: Two new species of Dasyurid Marsupial from the Pilbara Region of Western Australia.

Among Mammals, the most diverse groups tend to be those which feed on Insects. In Australia, about a quarter of all land Mammals belong to the Dasyuridae, which ate insectivorous and sometimes carnivorous Marsupials. The genus Planigale currently contains four species of Shrew-like insectivorous Marsupials, weighing between 3 and 17 g, which are found across most of the continent, with a fifth species on the island of New Guinea, although molecular studies have suggested that the genus probably contains more diversity than is reflected in this classification. Australia's indigenous Mammals have suffered greatly since the arrival of Europeans, with sharp declines in their numbers still being seen even in parts of the continent with few Human visitors, which makes having an accurate inventory of Australian Mammal species essential to conservation efforts.

The four currently described species of Planigale from Australia, Planigale gilesi, Planigale maculata, Planigale ingrami, and Planigale tenuirostris, are widely distributed in northern and eastern Australia. None of these species are considered to be threatened, but the two most widespread species, Planigale ingrami, and Planigale tenuirostris, have been shown to contain very high levels of genetic diversity, which may indicate that they are actually multiple species with much smaller ranges, and therefore potentially at conservation risk. 

The last major revision of the genus Planigale was carried out in 1976 by zoologist Michael Arche, but since that time genetic methods have become available, with several studies having suggested that there might be one or two undescribed species belonging to the genus present in the Pilbara Region of northerm Western Australia.

In a paper published in the journal Zootaxa on 14 August 2023, Linette Umbrello of the School of Biology and Environmental Science at the Queensland University of Technology, and Collections and Research at the Western Australian Museum, Norah Cooper, also of Collections and Research at the Western Australian Museum, Mark Adams of the Department of Biological Sciences at the University of Adelaide, and the Evolutionary Biology Unit at the South Australian Museum, Kenny Travouillon, again of Collections and Research at the Western Australian Museum, Andrew Baker, also of the School of Biology and Environmental Science at the Queensland University of Technology, and of the Biodiversity and Geosciences Program at Queensland Museum, Mike Westerman of the Department of Environment and Genetics at La Trobe University, and Ken Alpin, again of Collections and Research at the Western Australian Museum, and of the Australian Museum Research Institute at the Australian Museum, formally describe two new species of Planigale from the Pilbara Region.

The approximate distributions of the four currently recognised species of Australian Planigale with Pilbara distributions indicated with arrows. Umbrello et al. (2023).

The first new species described was originally identified as a candidate species in the first ever genetic study of the group, published 1995, in which a team led by Jodie Painter of La Trobe University used the mitochondrial cytichrome b gene to determine the relationships between different species within the genus Planigale. At the time. the candidate species, identified only as Planigale 1, was known from only a single specimen, which was one of only two specimens from Pilbara included in the study (the other specimen was also identified as a new species, Planigale 2, but was later found to belong to a separate genus), but subsequent genetic studies have consistently recovered this species as a separate clade.

Umbrello et al. formally name Planigale 1 as Planigale kendricki, in honour of Peter Kendrick, in recognition of his major contribution to the understanding of the vertebrate fauna of north-western Australia. Planigale kendricki is large for a species of Planigale, with a maximum recorded weight of 12.5 g and a maximum recorded length of 74 mm (excluding the tail). Females are smaller than the males, with a maximum recorded weight of 9.5 g and a maximum recorded length of 69 mm. It is more reddish than other species of the genus, with its back and flanks covered by a thick coat of orange-tan fur with patches of dark brown, while the hair of the underside is grey, changing to yellow or even brown at the tips.

Planigale kendricki. Note the rufous, orange-tan colouration of the fur and the orange eye ring.  Roy Teale in Umbrello et al. (2023).

Planigale kendricki is found across the Pilbara and the surrounding area of northern Western Australia, including the Cape range Peninsula, Ashburton and Gascoyne regions, with specimens reported from the Great Sandy Desert and Little Sandy Desert, Lake Auld, and Mandora near Eighty Mile Beach. It appears to favour areas with exposed bedrock, including sandy plains, scree slopes and rocky creek beds. 

Proposed distribution of Planigale kendricki inferred from specimens at the western Australian Museum (blue dots) that were examined during this study. the border of the Pilbara region is shown by the dashed line in inset A. Umbrello et al. (2023).

The second new species was first identified as a candidate species in a study led by Mark Blacket of La Trobe University and published in 2000, in which a much larger selection of Planigale specimens were examined, and a phylogeny for the genus developed using the 12S rrNA gene sequence. Blacket et al. identified this candidate species as Planigale Mt Tom Price, in reference to the area where it was discovered. This species was also recovered by subsequent genetic studies in 2009, 2016, and 2020, which looked at different gene sets.

Umbrello et al. formally name Planigale Mt Tom Price as Planigale tealei, in honour of Roy Teale, for his support for the work of the Western Australian Museum over many decades, and for collecting many of the specimens on which the description of the species is based. Planigale tealei is small for a species of Planigale, with a maximum male size of 6.1 g and 62.5 mm in length (excluding the tail), and a maximum female size of 4.7 g and 60 mm in length. Its back and sides are covered with a thick, greyish brown coat, paler on the flanks, and pale on the underside.

Planigale tealei (WAM M62896). Linette Umbrello in Umbrello et al. (2023).

Planigale tealei appears to be largely restricted to the Pilbara Region, with very few records outside of the area. It us usually encountered on cracked clay soils in areas with plenty of exposed rocky outcrops, preferring more clay-rich soils.

Proposed  distribution  of Planigale  tealei  inferred  from  specimens  (pink  triangles)  in  the western  Australian Museum that were examined during this study, including southern locality of Waldburg Station. the border of the Pilbara is shown by a dotted line in Inset A. Umbrello et al. (2023).

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Looking for variations in Human generation times over the past 250 000 years.

Generation time, i.e. the difference in age between parents and their children, is thought to have played a major role in Human history, and it is common to refer to significant events, such as the reaching of new landmasses or exchanging DNA with other Hominids, as having happened a number of generations ago. When such statements are made, it is generally assumed that generation times will have remained constant throughout Human history, and that we can estimate the number of generations to have passed since a particular event by extrapolating from the generation times of modern hunter-gatherer populations. However, there is no particular reason to believe that either assumption is true; population times among modern Human societies are known to vary independently for males and females, and in response to a wide range of social and environmental factors, while generation times vary considerably between different groups of modern hunter-gatherers. Furthermore, generation time can be shown to have evolved since our separation from our nearest Ape relatives, as well as within the Great Apes as a group.

Another method used in previous attempts to estimate the generation time of past Humans has been to use the rate at which DNA mutates between generations, measured against samples of ancient DNA from 40 000-45 000 years ago. This probably gives a more realistic estimate of the number of generations that have passed, and therefore the length of each generation, but is averaged across both genders, and only looks a limited distance into the past.

In a paper published in the journal Science Advances on 6 January 2023, Richard Wang of the Department of Biology and Department of Computer Science at Indiana University Bloomington, Samer Al-Saffar, also of the Department of Computer Science at Indiana University Bloomington, Jeffrey Rogers of the Human Genome Sequencing Center and Department of Molecular and Human Genetics at Baylor College of Medicine, and Matthew Hahn, again of the Department of Biology and Department of Computer Science at Indiana University Bloomington, present the results of an attempt to estimate Human generation times, for both sexes and across several different populations, spanning the past 250 000 years.

As Humans age, they accumulate an increasing number of mutations in their genetic code, and pass this on to their descendants. Wang et al. used data from an Icelandic study, in which the ages of parents at the time of conception were known, to model the six potential types of single nucleotide mutations, establishing that some became significantly more common with age, while others did not, thus providing a clock by which to estimate the age of unknown parents at the time of conception. 

The mutation spectrum changes with human generation time. (A) Data on de novo mutations from 1247 Icelandic trios were used to train a model that predicts the effect of both maternal and paternal age on the mutation spectrum. (B) Data from 25.3 million segregating variants whose date of origin was estimated were used to assess the mutation spectrum at different periods in the past. The mutation spectrum from each time period (bin) was used as input to the model from (A) to estimate the generation interval for males and females. (C) Differences in the frequency of each of the six different mutation types through time, as compared to the most recent time period (smoothed lines from local regression). Wang et al. (2022).

All living Humans are thought to be descended from a single population living about 250 000 years ago. By combining this with their data on age related mutation rates, Wang et al. estimate that the average generation time over this period has been 26.9±3.4 years. Furthermore, they were able to record differences between the sexes in their data, giving an average male generation time of 30.7±4.8 years, and an average female generation time of 23.2±2.0 years. Furthermore, Wang et al. are able to detect changes in the signal over time, suggesting that the average Human generation span was 24.9±3.5 years about 250 generations (or approximately 6700 years) ago, having declined from a peak of 29.8±4.1 years about 1400 generations (or approximately 38 000 years) ago, which would have been just before the Last Glacial Maximum. These estimates are, however, across multiple Human populations.

The study shows a longer generation time for males than females across all timespans, something which tallies with our understanding of modern Human cultures, 99% of which typically see such a longer male generation interval. Wang et al. note that much of the variance in generation intervals seem over time is connected to male generation intervals, while female intervals remain more constant. They suggest that the reason for this is likely biological rather than cultural, with Male humans typically remaining fertile for about 20 years longer than females. This creates the possibility for social structures to create considerably more variation in male generation time than in female generation time. Thus the difference in average generation time is strongly connected to a difference in male generation time in all but the most recent period, during which an overall increase in generation time has been linked to an increase in both male and female generation intervals, and the female generation interval appears to be larger than at any point in the past 250 000 years.

Wang et al. also looked at variations in generation interval between Human populations, considering four major geographical groups, Africans, Europeans, South Asians, and East Asians, although they note that beyond about 2000 generations ago the ancestors of all of these groups were likely to have been living in Africa, while about 10 000 generations ago all of these groups would have been descended from the same ancestors.

It was found that over the past 1000 generations, the average generation time for European and South Asian populations had increased slightly, while that for East Asian and African populations had remained relatively constant. Over the past 40 000 years, Europeans have had an average generation time of 26.1 years, slightly lower than the East Asian average of 27.1 years, but beyond this, the generation time for all non-African populations grows progressively shorter further into the past. Over the past 10 000 generations all non-African populations have shown significantly lower average generation times than African populations, with an average of 20.1±3.9 for East Asians, 20.6±3.8 for Europeans, and 21.0±3.7 for South Asians, compared to 26.9±3.5 for Africans.

This strongly suggests that different time scales should be used to calculate generation length in Africa (roughly 27 years per generation) and outside Africa (20-21 years per generation). Wang et al. note that, since the generation times for non-Africans dating back more than 2000 generations, when they would presumably have been living in Africa, these differences are in fact between different groups living on the same continent, suggesting that considerable variation in the population on that continent (which is considerably genetically more diverse than the rest of the planet) may remain hidden.

Change in generation interval across different Human populations. Generation intervals were estimated in ancestors of four major continental Human populations included in the 1000 Genomes Project; sex-averaged generation intervals are shown here. Confidence intervals for each population were  obtained by bootstrapping. The inset shows results from including polymorphisms that  date back to 78 000 generations ago; note that  age estimates of mutations in the very distant past  have  decreased accuracy. Abbreviations: AFR, Africa; EAS, East  Asia; EUR, Europe; SAS, South Asia. Wang et al. (2023).

Wang et al.'s study improves considerably on our previous understanding of the spontaneity of genetic mutations, and uses this information to make estimates about Human generation times in the past which were previously impossible. Their results are compatible with previous studies which have estimated generation times over the past 40 000 years, but extend the period covered by the estimate back much further, to 250 000 years before the present. While they suspect that the convergence of the Human race back to a single population about 10 000 generations in the past will prevent this model from looking back any further, Wang et al. believe that larger data sets may in the future allow for a much more detailed understanding of generation times within individual populations over the past 100 generations, particularly as parts of this period can be covered by historical birth records.

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Acanthaster benziei: A new species of Crown-of-thorns Starfish from the Red Sea.

Crown-of-thorns Starfish, Acanthaster spp., are highly distinctive Starfish found across the tropical Indo-Pacific region from the east coast of Africa to the west coast of Mexico, which get their popular name from the covering of long, venomous spines found in most species. They are typically corallivorous, feeding on Coral Polyps by extruding their stomachs and digesting them externally. Notably, Crown-of-thorns Starfish can undergo sudden rapid population increases, known as outbreaks, which can lead to large areas of Coral Reefs being denuded of their living Polyps, something of great concern to conservationists at a time when Coral Reefs are facing a range of other threats, which has led to them being one of the most extensively studied groups of Marine Invertebrates.

Crown-of-thorns Starfish were first described by the German naturalist Georg Eberhard Rumphius in 1705, and given their own generic name, Acanthaster, by the French palaeontologist François Louis Paul Gervais  in 1841. For a long while, only two species were described within the genus, Acanthaster planci, the typical, long-spined, venomous, corallovorous form, and Acanthaster brevispinus, a shorter-spined, non-venomous form, which does not feed on Corals. However, genetic studies carried out within the past three decades have shown that Acanthaster planci is in fact a species cluster, made up of a number of physically very similar species (cryptospecies), which are nevertheless genetically distinct, which often appear to have diverged from one-another a long time ago. 

Based upon this, it was suggested that the original species should be split into four different species, each inhabiting a different geographical area; the Pacific, the Southern Indian Ocean, the Northern Indian Ocean and the Red Sea, which each of these species probably needing further division into several subspecies. Subsequent studies have indeed confirmed that the Pacific, North Indian Ocean, and South Indian Ocean populations are in fact separate species, although genetic material from the Red Sea population has not, until now, been available.

In a paper published in the journal Zootaxa on 17 November 2022, Gert Wörheide of the Department of Earth and Environmental Sciences Palaeontology and Geobiology, and the GeoBio-Center at Ludwig-Maximilians-Universität München, and the Bavarian State Collection of Palaeontology and Geology, Emilie Kaltenbacher and Zara-Louise Cowan, also of the Department of Earth and Environmental Sciences Palaeontology and Geobiology at Ludwig-Maximilians-Universität München, and Gerhard Haszprunar, also of the GeoBio-Center at Ludwig-Maximilians-Universität München, and of the Bavarian Zoological State Collections, describe the Red Sea population of Crown-of-thorns Starfish as a new population.

The new species is named Acanthaster benziei in honour of marine biologist John Benzie, for his extensive work on Crown-of-thorns Starfish. The description is based upon four specimens collected from species within the territorial waters of Saudi Arabia by  Sara Campana and OliverVoigt in 2017.

Typical colouration of Acanthaster benziei. (A) GW4081 (Paratype, hiding during the day under a crevice), Al-Lith, Saudi Arabia, (B)–(D) Thuwal Reefs, Saudi Arabia. Approximate diameter of specimens is 25–30 cm. Oliver Voigt & Gert Wörheide in Wörheide (2022).

Acanthaster benziei is a large Starfish with a convex disk and 11-14 arms (the range for the genus being 10-25), of uneven lengths, and tapering to a point. Each arm has two rows of ambulacral tube feet, which have flattened tips and lack suckers. The central disk of the species is 28-65 mm across, with an aboral (upper surface) covered in papulae (pimples) arranged in an apparently random manner. Both surfaces are covered in calcareous ossicles (plates) and spines. These Starfish are grey-green to grey-purple in colour, although the aboral spines are orange or red. The papulae on the aboral surface of the central disk can form darker patterns, giving this surface a 'bulls-eye' appearance.

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