Reader’s wildlife photo

June 20, 2022 • 8:00 am

It’s a holiday and I want to have a bit of fun today, so we’ll have just a brief edition of the wildlife photos: in fact, just one.  But be sure to keep sending them in!

This comes from Claudia Baker, whose narrative is indented. Click on the photo to enlarge it.

This snapping turtle (Chelydra serpentine) made an appearance in my driveway a couple of weeks ago. As I live quite close to a wetlands area, about 30 km southwest of Ottawa, Ontario, I often get turtles in my driveway and yard this time of the year as they are looking for suitable places to lay their eggs.
Look at the size of this beast! I was taking out the garbage in the evening when I spotted her. She backed under the car a little in her fright. Those claws!

The moral: check around your car for turtles and other wildlife before driving off!

Readers’ wildlife photos

May 27, 2022 • 8:00 am

Don’t forget to send your photos in! There’s a prize! (You get to show them off to a lot of people).

Today’s batch comes from Daniel Shoskes, whose captions and IDs are indented. Click on the photos to enlarge them.

It’s been a few years since my last submission so I thought I would share a few photos from a recent trip to Belize. Brown Iguana, Toucan (the national bird of Belize), Howler monkeys, nurse sharks and a Roseate Spoonbill. [JAC: not in order, but I trust you won’t be confused.]


Happy World Turtle Day!

May 23, 2022 • 9:47 pm

by Greg Mayer

I’ve only just learned that today, Monday, May 23, is World Turtle Day. Jerry noted the holiday in today’s Hili Dialogue, but I missed it, so my apologies for posting so late in the day.

The day is sponsored by American Tortoise Rescue, so I thought it appropriate to share a video of Zelby, a tortoise who is an acquaintance of mine.

Zelby is a member of the genus Testudo, and is one of the species from the Mediterranean area which also extend eastward into Asia. The species might be T. horsfieldi, the Russian Tortoise. There are several forms of this group popular in the pet trade; the alpha systematics is still in flux, and I don’t know the group well.

Zelby is dining on mixed greens and cucumber slices.

Readers’ wildlife photos

May 18, 2022 • 8:00 am

Today we have an assortment of diverse photos by Tony Eales from Queensland. His captions and IDs are indented, and please click on the photos to enlarge them.

By the way, if you have good photos you’d like to send me, see the link on the left sidebar of this site, “How to send me wildlife photos.”

I came across this Aseroe rubra Anemone Stinkhorn Fungus the other night. This fungus is relatively common here in eastern Australia but by daytime they have grown into a 100mm high tree-like shape with deep red tentacles and the light brown part collapsed into a dark brown-black goo. They start out as a white egg shape emerging from rotting mulch that then bursts revealing the tentacles. You can see the remains of the egg in the photo.

I don’t often photograph vertebrates but I’ve seen a few cool ones of late. This one is  or Red-bellied Black Snake. They are specialists of frogs and smaller reptiles. They are one of the more common snakes in my area but had their numbers reduced by the spread of the introduced Cane Toad (Rhinella marina), which is highly poisonous. Red-bellied Blacks are dangerously venomous but reluctant biters, even so, being very common they are responsible for a few bites every year.

For their size their venom is among the least dangerous of the Australian elapids with the only recorded deaths being early on and of questionable identification.  My most frequent encounters with them is to see the tail rapidly disappearing into the bush. It was good to have a calm subject to photograph.

Another lovely snake I found recently is Cacophis squamulosus, the Golden Crowned Snake—a rainforest specialist living in the leaf litter hunting insects and small reptiles. Again I normally see only a flash disappearing into the leaf litter, but this one was out on a fence at night time and I managed a few snaps before it retreated.

Another exciting find for me was this Lycid beetle larva. The larvae of these beetles are some of the strangest animals I’ve seen. I have no idea of the species and adult lycids are very similar looking to one another so I have a devil of a time getting them to species level as well.

But by far my favourite find recently was the wonderful Ordgarius magnificus AKA the Magnificent Bolas Spider. These are large spiders, the abdomen being about the size of the end of your thumb.  Their eyes are very strange, being perched on top of a thin red tubercule in the middle of their large cephalothorax.

By day they hide in a retreat composed of leaves and twigs lashed together [below] with a few strong web lines. Most people only see their (up to a dozen) 5 cm-long, dangling egg sacs, each containing up to 600 eggs.

Not only are they large and colourful, but their predatory behaviour is extraordinary. They hang at night from a simple web and create a dangling thread with large globs of sticky glue dotted along it. They exude a pheromone that attracts the male moths of one particular species. When they detect the vibrations of an approaching moth they swing the sticky bolus around and around which catches the moth. I am reliably informed that the vibrations from a nearby diesel engine running will also elicit this predatory behaviour.

The  hideout:

I found this one hunting, but my light disturbed it and it reeled in and reconsumed its bolus unfortunately so I did not get shots of the hunting behaviour.

Readers’ wildlife photos

February 5, 2022 • 9:00 am

Today’s photos are of the Galápagos Islands and its wildlife, taken by reader Joe Baldassano. His commentary and IDs are indented, and you can enlarge his photos by clicking on them.

Attached are some photos of my November 27 thru Dec 6, 2021 trip to the Galapagos Islands.

First, you will recognize the Island below (not named in the attachment) as Daphne Major. I want to mention to your readers that this was the site of Peter and Rosemary Grant’s studies of finches which led to the book The Beak of the Finch, a work I highly recommend. This island is off limits to visitors without special permission from the government.

During this trip, I visited the islands of Genovesa, Balta, St. Cruz, Santiago, and Isabella.  Most of the wildlife has no fear of humans and I believe credit for that rests with the government of Ecuador.  All excursions into the islands are closely regulated and visitors are accompanied by a well-trained naturalist. You can get very close to the animals, but no contact is permitted.

Each island offered an opportunity for snorkeling, and I was able to swim with sea lions, fur seals, sea turtles, manta rays, white tip sharks, and penguins. On one particular snorkeling excursion, a large sea gull did not welcome our presence and swam over to me and began pecking at my goggles; he/she was not happy and began pecking at my arm. I just swam backwards and the gull focused attention on my snorkeling buddy by ripping one of the filters off of his underwater camera.  It was very exciting provided and comic relief for all of us.

Seeing the giant tortoises and all of the wildlife found nowhere else was a gift,and I would encourage any follower of your WEIT site to put the Galapagos Islands on their bucket list.

Nazca Booby (chick):  Sula granti:

Blue Footed BoobySula nebouxii:

Galapagos Sea LionZalophus wollebaeki:




Magnificent FrigatebirdFregata magnificens:

Galapagos HawkButeo galapagoensis: 

Galapagos penguinSphensicus mendiculus: 

Galapagos short-eared owlAsio flammeus:

Ground Finch: (I do not know which finch I photographed; there are six different ground finches):

Land Iguana:  Conolophus subcristatus:

Red footed booby: Slua slua websteri:

With egg:

Round Shell Tortoise: Chelonoidis Nigra:

Saddleback Tortoise: Chelonoidis becki:

Sea (Marine iguana): Amblyrhynchus cristatus:

Green Sea TurtleChelonia mydas mydas:

Swallow-tailed gull: Larus furcatus:

Yellow warbler: Dendroica petechia aureola:

Darwin Research Station [b: An especially good photo!]:

Readers’ wildlife photos

January 21, 2022 • 8:30 am

Today’s photos are from Athayde Tonhasca Júnior, and the topic is biological nomenclature: how these creatures were named. Do read all the captions. The descriptions are of course from Athayde, and are indented. You can enlarge the photos by clicking on them.

This beetle had the bad luck of being described in 1937 by Oskar Scheibel, an Austrian amateur entomologist. Scheibel, supposedly an admirer of a powerful compatriot of sinister reputation, named the new species Anophthalmus hitleri. The elusive, eyeless cave beetle was already rare at the time of its description, but since then its numbers have plunged because of collectors and wackos obsessed by Nazi memorabilia: specimens have even been stolen from museums and sold on the black market for hundreds of pounds. Because of poaching, A. hitleri is now endangered and restricted to a few Slovenian caves. This beetle has been a flagbearer for the Woke Brotherhood’s Zoologist Chapter, which is on a mission to change names inspired by disreputable people. The International Code of Zoological Nomenclature has resisted these demands, with good reason. Once a precedent is set, the Latter-day Puritans will demand the renaming of all creatures baptised after shady types such as Darwin, Huxley, John Muir and J.K. Rowling (more than ten species were named after Harry Potter characters); the moth Neopalpa donaldtrumpi and the beetle Agathidium rumsfeldi would have to go, although the spider Aptostichus barackobamai is probably safe. Moralistic renaming would be foolish and cause immense confusion. Also, the Righteous Mob should consider that species naming is not necessarily laudatory: among other taxonomic stabs, Linnaeus made good use of the seed bug genus Aphanus (from the Greek for ‘obscure’) to name a species after his estranged student Daniel Rolander: Aphanus rolandri.  Indeed, naming a blind, cave-dwelling beetle after the Führer could be seen as a less than flattering move.

When a team of herpetologists examined a snake stored in a collection for 42 years, they discovered it had eaten another snake. Such findings are not particularly rare, but that semi-digested dinner turned out to be a hitherto unknown species – in fact, a new genus altogether. The image is an artist’s rendition of the meal before its consumption. The newcomer to science was christened Cenaspis aenigma: the enigmatic dinner snake, a name derived from the Latin cena(dinner) and aspis (snake) (Campbell et al., 2018. J. of Herpetology 52: 458-471). The snake, from Mexico’s Chiapas highlands, has never been seen in the wild, probably because it’s rare, elusive and nocturnal. Or it has gone extinct. This case was not unique:  the ant Lenomyrmex hoelldobleri was discovered in a barf sample collected from an Ecuadorian frog, and named after distinguished myrmecologist and E.O. Wilson’s collaborator, Bert Hölldobler.

It took 42 years for Darwinilus sedarisi to come to light, which is understandable because the creature was hidden in the belly of another snake. One rover beetle on the other hand remained unknown for over 180 years despite being in plain sight, so to speak: the specimen was catching dust in the Natural History Museum (London). American entomologist Stylianos Chatzimanolis borrowed it to discover that the beetle belonged to an undescribed genus. As it had been collected in Argentina by Charles Darwin during a HMS Beagle stopover, Chatzimanolis deservedly named the genus Darwinilus. For the species epithet, he chose sedarisi to honour raconteur David Sedaris, who is famous here in Britain for his books, BBC Radio 4 monologues and litter-picking activism (Chatzimanolis, 2014. Zookeys 379: 29–41).

Every name has a story, even if it’s a sketchy one. Paul Williams, a bumblebee specialist at the Natural History Museum (London), painstakingly tracked down scraps of information about a shabby, mislabelled specimen collected about 200 years ago and sitting in the Oxford University Museum of Natural History. Paul concluded it belonged to Bombus rubriventris, an extinct bumble bee from the Brazilian Atlantic Forest, one of the world’s richest and most threatened biomes (Williams, 2014. J. of Natural History 10.1080/00222933.2014.954022). We know nothing else about this bee; that pinned specimen lying inside a dark drawer is the only evidence left of a species that once buzzed from flower to flower, probably pollinating some lucky plants. Considering the greatest environmental disaster ever to befall Brazil, that is, the election of Jair Bolsonaro as president, certainly there will be more sad stories about extinct Brazilian species.

Ytu,the word for ‘waterfall’ in Tupi-Guarani (a group of native languages spoken in Brazil and Paraguay), is a suitable name for a genus of water beetles. So when entomologist Paul Spangler discovered a new species, how could he not name it Ytu brutus? (Spangler, 1980. The Coleopterists Bulletin 34: 145-158).

Entomologist Terry Erwin probably was one of the most prolific taxonomic punsters, and he had great fun with the ground beetle genus Agra. Erwin named more than a hundred Agra species, including Agra nola, Agra vate, Agra vation, Agra cadabra and Agra memnon. He also named Agra schwarzeneggeri, a beetle with unusually thick ‘arms’, and Agra eowilsoni, after E.O. Wilson. Erwin was witty, but also a great entomologist. His short, unpretentious paper where he hypothesized the existence of around 30 million species of insect on the planet has been cited hundreds of times (Erwin, 1982. The Coleopterists Bulletin 36: 74–75). One subfamily, 2 genera and 47 species are named after him. Here is Agra vation:

John Epler, an expert on Chironomidae (non-biting midges) and other aquatic insects, made good use of his Classics education to honour his favourite band with a new species: Dicrotendipes thanatogratus, from the Greek thanatos (dead) and Latin gratus (grateful) (Epler, 1987. Evolutionary Monographs 9: 102).

A short explanation for those unfamiliar with the art of biological nomenclature: in scholarly texts, the first citation of a plant or fungus’ scientific name (rules for animals are slightly different) is followed by the name of the person who described the species, e.g., Amaranthus retroflexus L. (L. is a standard abbreviation for Linnaeus). When a name is changed, for example moved to another genus, the original authority goes in parenthesis, followed by the name of the person who made the change, e.g. Hyacinthoides italica (L.) Rothm. So when German mycologist Karl Wilhelm Gottlieb Leopold Fuckel discovered a new species of wood-rotting fungus, it was named Nectria applanata Fuckel. But some years later his compatriot Carl Ernst Otto Kuntze moved the species to another genus, resulting in the delightful Cucurbitaria applanata (Fuckel) Kuntze (Gräfenhan et al., 2011. Studies in Mycology 68: 79-113).

The people of Guadeloupe have a soft spot for their only large wild mammal: the raccoon. The masked creature is pictured on stamps, toys, and in a national park logo. Raccoons are notorious for raiding crops and wrecking nests of wild bird and sea turtles, but these shenanigans do not dent their popularity: islanders have long treated the Guadeloupe raccoon (Procyon minor) as a protected species. Then in 2003, the celebrity status of the Guadeloupe raccoon suffered a serious blow. By examining museum specimens, taxonomists discovered that Procyon minoris in fact a subspecies of the common raccoon, Procyon lotor. (Helgen et al., 2008. J. Mammalogy 89: 282–291). This seemingly finicky academic study led to all hell breaking loose: the common raccoon is an alien species in the Caribbean islands. Even worse as PR goes, Guadeloupe is an overseas department of France, so legally speaking, the archipelago is part of the European Union. As the common raccoon is listed as a European invasive species, France has the obligation to eradicate or control it. The people of Guadeloupe were not having any of it: there have been strong words between locals and authorities.

Nessiteras rhombopteryx– The scientific name given to the Loch Ness monster by Sir Peter Scott, renowned ornithologist, conservationist, naval officer and Olympics medallist, and Robert Rines, American lawyer and composer (Scott & Rines, 1975. Nature 258: 466-468). Many were bewildered by Scott’s action – Rines on the other hand was well known in the woo-woo field of cryptozoology. That Nature went along with it was equally puzzling – one can imagine that Scott’s reputation helped the publication. Scott reasoned that a scientific name would give legal protection to the beast, in case it was real. But Scott was lambasted for promoting pseudo-science. Later, a British politician and newspaper – perhaps in an effort to protect the reputation of a British icon – claimed that the name was an anagram for ‘Monster hoax by Sir Peter S’. Rines denied it, pointing out that ‘Yes, both pix [a reference to the paper’s pictures] are monsters – R‘ was an alternative letter arrangement. In other words, the confession anagram was a coincidence. The paper was unlikely to have been a hoax, considering the time and effort Scott dedicated to this fantasy. He created the Loch Ness Phenomena Investigation Bureau, goaded colleagues into reviewing evidence, and even pulled strings with the Royal Navy to obtain military searchlights to sweep Loch Ness. Incidentally, Scott & Rines taxonomic foray was in vain: the scientific name (which was drawn from the Greek for ‘Ness inhabitant with diamond-shaped fin’) was not valid because it lacked a type specimen (a specimen on which the description and name of a new species is based). The International Code of Zoological Nomenclature, which rules on these things, would recognise a description based on photos. But certainly not the paper’s blurred images, which in all likelihood were doctored (but not taken by the authors). Scott may have gone momentarily wobbly, which happens to the best: Newton was an alchemist, Nobel Prize double winner Linus Pauling promoted vitamin C to cure cancer, and Alfred Russel Wallace believed in communicating with spirits.

Readers’ wildlife photos

January 17, 2022 • 8:30 am

Our contributor today is Christopher Starr, a retired Professor of Entomology at the University of the West Indies in Trinidad and Tobago.  His photos span a range of taxa. Christopher’s captions are indented, and you can enlarge his photos by clicking on them. (See his first contribution here.) His captions and IDs are indented, and you can enlarge the photos by clicking on them.

In the early morning, before the sun got hot, I consistently saw bright red velvet mites (Trombiculiidae) walking in the open on a sandy surface.  They were large (about the size of a raisin), soft-bodied and very conspicuous, yet the abundant agamid lizards were not eating them.  Wondering if they were protected by defensive chemicals, I tasted one, and sure enough.  It was so dreadfully bitter that I couldn’t bring myself to try another, so my sample size remains at one.  Ghana.

We are all familiar with mimicry, in which the mimic gains an advantage when the predator mistakes it for something else: a type-1 error.  Those of us with an eye for mimicry sometimes make a type-2 error by mistakenly seeing a deception where there is none.  Coming upon this dried, twisted vine, my reaction was “Aha, a snake camouflaged as a vine.”   Georgia.

The pachyrhychine weevils are a distinctive, extremely hard-bodied group almost entirely restricted to the Philippines and the Pacific islands fringing Taiwan. Pachyrhynchus tobafolius (first photo) is sympatric with an unidentified otiorhychine weevil (second photo), which has the appearance of being one of its mimics.

Although it is highly venomous, the fer-de-lance, Bothrops asper, avoids contact with humans and other large animals.  Note the effective camouflage of this one, which was lying immobile against a backdrop of vegetation. Trinidad.

This male Anolis lizard in the process of shedding his skin ate the old skin as it came loose.  Costa Rica.

Trinidad’s Pitch Lake is analogous to the La Brea Tar Pits in California.  Unlike La Brea, the Pitch Lake has not been mined for fossils, which it very likely contains.  This caiman was trapped in the surface tar and gradually sinking into it, possibly on its way to becoming a fossil.  Trinidad.

JAC: I’ve inserted a 2016 photo of Pitch Lake taken from Wikipedia:

A primary defensive feature is one that operates all the time, while a secondary defensive feature comes into play only when a threat is perceived.  Tortoises present my favorite example of a primary defense enhanced by a secondary defense.  The hard shell is always present, but when the tortoise is threatened it withdraws its head and feet tightly inside the shell. Mexico.

This newly-hatched Gonnatodes gecko was fully active from the moment it broke out of its shell.  Trinidad.

In studying the responses of various orb-weaving spiders to a simulated predatory disturbance, I found that common cross spiderAraneus diadematus, has one that I have not seen in any other. In the early stages of the disturbance, the spider raises its forelegs as if to parry the intruder.  Italy.

In some parts of its range, the large pink-toed tarantula, Avicularia avicularia, is common in rural buildings, including in my house.  I have often seen visitors startled and even fearful when encountering one fo these, but I like having them around. Trinidad.

I have usually found this Hersilia sp. building its web on the surface of tree trunks and sitting in the middle of it, flattened and well camouflaged.  Philippines.

Cnidoscolus urensl is commonly known as “burn bush” or “mala mujer” on account of the highly urticating needles on its leaves, stems and fruits.  Where this plant is very abundant, we found the orb-weaving spider Argiope argentata preferentially basing its web on this plan. St Vincent & the Grenadines.

This Myrmarachne sp. [JAC: note that this is a spider] has the appearance of a specific Batesian mimic of a Crematogaster ant that is abundant in its habitat. Taiwan.

Tortoise eats bird (by Greg Mayer)

January 12, 2022 • 1:15 pm

by Greg Mayer

Last month Matthew asked me about herbivory in reptiles, and part of my reply was that there are few or no reptiles that are exclusively herbivorous. The ones that came closest that I could think of were the true land tortoises (family Testudinidae, sensu stricto). I wrote, “some true tortoises are pretty close to vegetarian, but I’d still say they are at least facultatively omnivorous.” And sure enough, shortly after I ran into the following:

The video, of a giant tortoise (Aldabrachelys giganteus) on the island of Fregate in the Seychelles eating a noddy (Anous tenuirostris, a member of a genus of common tropical terns), accompanied a paper on the incident published last August by Anna Zora and Justin Gerlach in Current Biology. Wikipedia makes an amusing observation about noddies:

Anous is Ancient Greek for “stupid” or “foolish”. Noddies are often unwary and were well known to sailors for their apparent indifference to hunters or predators.

The sailors were right– the noddy, it seemed to me, though not fledged, could have gotten away. Perhaps it had a strong aversion to moving away from the immediate vicinity of its nest.

We’ve encountered island biologist Justin Gerlach before here at WEIT, where I noted his paper on an Aldabran tortoise’s ocean journey.

The Aldabra tortoise at Kimbiji, shortly after its discovery in December 2004. Photograph: C. Muir. Figure 1 of Gerlach et al. (2006).
An Aldabra tortoise that came ashore at Kimbiji, Tanzania, in December 2004. Note the barnacles acquired during its adventure at sea. Photograph: C. Muir. Figure 1 of Gerlach et al. (2006)

We’ve encountered Justin Gerlach before here at WEIT, where I noted his paper on an Aldabran tortoise’s ocean journey (picture just above). The Fregate tortoises are probably introduced from Aldabra, but the systematics of Indian Ocean tortoises is not entirely settled, and there have been a number of claims of tortoises surviving from the Seychelles populations that are usually thought extinct.

As far as reptile feeding in general goes, snakes, crocodilians, and the tuatara are exclusively carnivorous (in the broad sense of feeding on any kind of animals, including carrion), lizards range from carnivorous to omnivorous with a large herbivorous component (e.g. iguanas), and turtles are omnivorous, ranging from mostly carnivorous (e.g. snapping turtles) to mostly herbivorous (e.g. true tortoises).

Gerlach, J., C. Muir and M.D. Richmond. 2006. The first substantiated case of trans-oceanic tortoise dispersal. Journal of Natural History 40(41–43): 2403–2408.

Zora, A. and J. Gerlach. 2021. Giant tortoises hunt and consume birds. Current Biology 31: R989-R990.

Readers’ wildlife photos

January 10, 2022 • 8:30 am

Today’s photos, a mixed bag of taxa, come from reader Chris Taylor in Australia (that almost rhymes!).  His notes and IDs are indented, and you can enlarge his photos by clicking on them.

Another set of photos:  all were taken at home on my property outside Canberra.

Black Fronted DotterelElseyornis melanops, at the edge of the dam next to the house.  These are quite common visitors, and have even tried to breed here. Unfortunately, their nest attempts have not met with success.

An Eastern Grey KangarooMacropus giganteus, on the dam above the house just before dawn.  Very common here; there are mobs of up to 50 that move between the forest reserves up above our house and the paddocks in the valley.

An Echidna, Tachyglossus aculeatus, ambling across one of the paddocks.

Eastern Long-necked TurtleChelodina longicollis. These are quite common in the farm dams and waterways around here.  Unfortunately, many fall victim to cars as they try to cross the roads – they just stop walking and retreat into their shell as a car approaches, with the inevitable result.

We quite often see snakes here.  The most venomous are the Brown snake, and the Red-bellied Black Snake, Pseudechis porphyriacus, pictured here. The Brown is reputed to have the third or fourth most potent venom of any snake, while the Red-belly comes in rather further down.  It is said that the red-belly will eat brown snakes, and so when they are around, brown snakes will not be a problem.  Just how truthful that is I can’t say, but the years when the red-belly was here we didn’t see a single brown.

A Jewel Beetle, Scutiphora pedicellata:

Welcome Swallows, Hirundo neoxena. The first photo is of a swallow nest and fledgeling in the roof of one of the sheds above where we parked our vehicles. So during the time when the young birds were still in the nest, we had to clean the car windows every time we wanted to drive out!

The second photo is of the swallows bathing in the dam below the house.  They would fly around, then almost hover for a moment, before dipping their breasts into the water.

Two photos of Willie Wagtails (Rhipidura leucophrys). A very common bird, and here all year.  First we see a bird coming in to land on a fence post.  The second is one of a nest.  This is constructed from spider web, and this nest was particularly cozy as it was luxuriously lined with Alpaca fleece that the birds had been able to gather from bits left in the paddock after we had shorn our animals!

Wonderful fossil dinosaur embryo shows birdlike “tucked” posture before hatching

December 24, 2021 • 11:00 am

This is one the most stunning fossils I’ve seen in a long time. It’s an almost perfectly preserved dinosaur embryo that somehow died in the egg during the Late Cretaceous (100 mya-66mya). It’s not just amazing for its preservation, but also for the posture of the unhatched embryo, which resembles the posture that modern bird embryos (an also early birds themselves) assume soon before hatching. The inference is that the behaviors that precede hatching in birds, and help them through the tough process of getting out of the egg, actually evolved from their reptilian ancestors—the theropod dinosaurs, of which this specimen is one.

The paper appears in iScience and is free; click on the screenshot below or get the pdf here.

I’ve really conveyed the gist of the paper in the first paragraph above, but you need to see this embryo! Click to enlarge; all the photos are high-resolution

(from paper): Figure 1. Oviraptorid embryo inside an elongatoolithid egg (YLSNHM01266) Abbreviations: cev, cervical vertebra; cv, caudal vertebra; dv, dorsal vertebra; f, femur; fi, fibula; II-1, pedal phalanx II-1; il, ilium; is, ischium; m, mandible; mt-I, metatarsal I; mt-III, metatarsal III; mx, maxilla; p, pubis; pm, premaxilla; r, radius; s, scapula; t, tibia; ul, ulna. Scale is 1 cm.


The specimen is given the number YLSNHM01266, and is described as a “new non-avian theropod dinosaur embryo. . . from the Late Cretaceous Hekou Formation of southern China.” No species name is given because without a fossil of an adult in the vicinity, we have no idea. We can tell, however, that it is a theropod dinosaur, and an “oviraptorid oviraptorosaur“.

Oviraptors constitute is a group of theropod dinosaurs of varying sizes, which lived in what is now North America and Asia. Fossils show that they had feathers, parrot-like beak mandibles, sometimes bony crests on the head, and walked on their hind legs. Paleontological analysis combined with phylogeny shows, as Wikipedia notes, that they are “close to the ancestry of birds.” (The ancestor of birds is thought by most but not all paleontologists to be theropod dinosaurs.)

Here’s a group of diverse ovoraptors from Wikipedia. You can see that their skeletons are more birdlike than those of other dinosaurs. Some scientists, indeed, group them with birds! Four species have been found with feather impressions, so it’s likely that the group (including the baby above) had feathers, but couldn’t fly. Maybe one of the species below is the adult that would have developed from the juvenile above!

Back to the fossil.  Here’s part of a later figure that helps you make sense of what’s what in the photos above. The air cell, also present in modern bird eggs, is to the right between the embryo and the shell.

If you want the technical description of the posture, here it is from the paper. I’ve bolded the important parts.

The articulated embryonic skeleton is preserved curled inside its egg (YLSNHM01266), with the skull positioned ventral to the body (Figure 1). The egg is elongate ovoid in shape with dimensions of 16.7 cm long by 7.6 cm wide, and has characteristics typical of the egg family Elongatoolithidae (see STAR Methods for eggshell analysis). The skeleton is almost complete, without much apparent postmortem disruption. The anterior surface of the skull faces toward the pointed pole and is situated about egg mid-length at the level of the ilium in-between the flexed hindlimbs, with a pes [foot] on either side. The anterior cervical vertebrae are in line with the long axis of the skull. The presacral vertebral column is strongly bent in an angular manner, so that the upper back of the embryo faces the blunt pole of the egg (similar flexion of the vertebral column is found in modern in ovo skeletons, e.g. Balanoff and Rowe, 2007: Figure 4, Day 18, and is not likely to be a taphonomic artifact). The skeleton is ∼23.5 cm in total length, measured from the anterior tip of the skull to the last preserved caudal vertebra, and occupies nearly the entire width of the egg and most of the length, with the exception of a ∼1.9 cm space between the dorsal vertebrae and the blunt pole of the egg. This space may represent the air cell, a space usually found between the back of the embryo and the blunt pole of bird eggs (e.g., Rahn et al., 1979). However, this inference is tentative and awaits further evidence. The posterodorsal, sacral and caudal vertebrae almost form a straight line along the long axis of the egg. Although the precise developmental stage of the embryo is unclear, it is likely to represent a late-stage embryo because the skeleton is well ossified and is large in size relative to the space inside the egg, as inferred in MPC 100/971 (Norell et al., 2001).

Note that the specimen is 23.5 cm, or a bit more than nine inches long: as long as a dollar bill and half of another one (American dollar bills are almost exactly 6 inches long, and can be used for emergency measurements).

When modern birds hatch, they assume this position as the first of three stages prior to hatching: “pre-tucking”, “tucking” and “posttucking” (we know this clearly because, sadly, many pre-hatched birds have been dissected from the egg). I won’t go through the complicated description of the changes in posture, but here’s how it happens in a chicken, with the fetal dinosaur placed between “pretucking” and “tucking”. “Membrane penetration” is when the bird uses its bill to get out of the membrane in which the embryo is enclosed, and “pipping” is when it begins to peck through the shell (often a long process).

Apparently birds always tuck their heads below their right wing, not their left, before pipping. How they know left from right (genetically) is beyond me; but somehow this asymmetry is coded in the DNA:

And here are three examples of embryonic oviraptors compared to a modern bird (chicken) at the assumed similar stages:

(from paper): Figure 3. In-ovo late-stage embryos of non-avian and avian dinosaurs (A) Oviraptorid specimens (MPC 100/971, YLSNHM01266 & IVPP V20183), which potentially correspond to various tucking stages. (B) Domestic fowl Gallus ontogenetic series (day 16-20) (modified from Rowe (2003)). Not to scale. Silhouettes modified from PhyloPic.

Now the authors are very careful not to overinterpret a single fossil, but I do think it’s likely that the oviraptor fossils show that their pre-hatching positions and behavior was passed on to birds, as oviraptors are phylogenetically close to the ancestor of birds (though we don’t know whether the ancestor of birds was an oviraptor).

The only question remaining is: do all dinosaur embryos—not just those closely related to the ancestor of modern birds—show similar embryonic behavior? The answer is, as usual, we just don’t know. There’s a severe shortage of well-preserved dinosaur embryos, as you might imagine One specimen of a sauropod, a distant relative, seems to show a different fetal posture than the ones above.

I hope we can find more fossil embryos, because, although behavior doesn’t fossilize, the correlates of behavior—represented by the posture of embryos—do. In that sense the way modern birds hatch might what some systematists call a synapomorphy: a character shared by two species (or groups) because it was present in an ancestor—in this case the common ancestor of the ovoraptors and modern birds. And it’s surely an adaptive synapomorphy, because birds that can’t get out of the shell don’t leave any genes behind.


Xing, L. et al. 2021.  An exquisitely preserved in-ovo theropod dinosaur embryo sheds light on avian-like prehatching posturesiScience, in press.