Please note that the Wolfcampian Permian age given the El Pueblo tracksite or ichnotelmafacies by outside geologists in 1990 will be changing to Kasimovian late Pennsylvanian. This is because of a newly found giant centipede trackway and the footprints of very large dragonflies. Please excuse the inconvenience.

Dimetrodon and Darwinism 

The fact that Dimetrodon's large toes (thicker digits) were located outwardly (Henry Ortiz, 2017, 2020) raises questions about Dimetrodon's continued evolution. In other words, might there have been a link between Dimetrodon's pes and early mammals, or primates, as some have suggested? Darwin's concepts of natural selection always apply insofar as preparedness for a changing environment. But when, if ever, did Dimetrodon's big toe switch from the outward side of the pes to the inside, as in humans? It appears that the species and their individual specialization was designed for a specific ecological purpose, in a specific time, in a specific world. Because of its sail, Dimetrodon had to cope with maintaining its balance when it was windy, or in heavy currents. Having the big toes on the outer side aided in maintaining side balance. Three premises about early life come to mind:

1. Watery environments within a feasible climate engendered fish and        terraqueousy.

2. Terraqueous environments led to terrestrial tetrapodism.

3. Low ozone-layer protection and abundant carbon dioxide led to bumpy    heat-deflecting skin in tetrapods and dinosaurs, as well as temperature      regulating sails on known and unknown tetrapods.  

All of the above triggered the life force that is life itself but within the confines of very specific environments that when destroyed or altered, killed off countless species. (Modern climate change has begun to exact a toll on certain species.) Some animals were able to adapt; some did not. The implication is that many species were a product of a specific time and space, and Dimetrodon may have been such a species. Even if destined to become extinct, Dimetrodon's temporal range of 23 million years far exceeds Man's temporal progression of six million years. Something tells me that any link from the late Carboniferous to humankind will involve the isolation of one or more tetrapods that habitually climbed trees to escape predators, with claws, thumbs and forefingers providing a grasping ability. 

        Dimetrodon Berea, Like Other Dimetrodons, Was a Narrow Animal

Photo above shows the first (ever?) measurable pes footprint distance of a Dimetrodon berea tetrapod from the El Pueblo facies. Like Dimetrodon elpueblus (straight claws), Dimetrodon berea (biforked claws) was a very narrow animal. The space between the pes footprints (smallest digit to smallest digit) suggest a distance of about 2.5 inches, maximum. That is not much of a sprawled posture. It appears that Dimetrodon berea was also slightly pigeon-toed, suggesting, perhaps, a lower sail that was less wind compromised. A question of balance comes to mind when studying the narrow footprints of sailed tetrapods. Nonetheless, able to range from swamp to swamp in broad, CO2-hot daylight, Dimetrodon berea was one of the early Permian's most active controllers of small amphibia.  

A change in geological age: Please note that the El Pueblo ichnotelmafacies (swamp facies) has been updated to Kasimovian age or late Carboniferous. Please read the Kasimovian age abstract by Henry Ortiz in academiaedu.com. Fossils differing from the early Permian constitute a very diverse assemblage equal only to a post-quintessential Kasimovian forested swamp and an obvious recent departure from a Carboniferous forested swamp represented by a small nearby lake. Some important late Carboniferous markers include evidence of Dimetrodons smaller than Dimetrodon grandis and myriapod traces varying from small to wide trackways. A geological abstract in the area of the Pecos mission monument by US geologists agrees closely with the beginning of the Permian as encompassed by the Rowe Mesa stratification from Permian to Triassic (Henry Ortiz 2024).  

Dimetrodon, the Hunter

Where else would Dimetrodon do most of its hunting if not inside swamps of the early Permian. This was its workplace. It's hard to call Dimetrodon a predator. A predator is one who preys for secondary gains. Dimetrodon was entrusted with regulating the superfluous numbers of amphibian hatchlings. It was an important link in the food chain. Hard to call Dimetrodon an it because it has assumed some kind of hero status deserving of a he. Dimetrodons were either male or female. Both genders were in the business of advancing their genes. And why would nature assign Dimetrodon such an elitist job? Because, unfair as it seems, those animals that had become more terrestrial during the early Permian were at the forefront of evolution. The evolution was aimed at populating dry land with early advanced pelycosaurs, early mammals and eventually tree climbers that would ultimately lead to the evolution of primates. And look at what human primates have done to the earth--but that is a different story.

      There was quite an interruption in terrestrial evolution during the intense volcanic activity that marks the Permian-Triassic boundary. As a new round of uplifting ensued, thunderous eruptions announced the web-like pattern of sill volcanic venting that incinerated many ponds and swamps, killing countless animals in the process. Many theorize that the excessive smoke degraded the environment considerably, atrophying evolution of both plants and animals. Somehow many species survived. The scant evidence of the first Triassic mammals in the US is limited to rat size species. Where are the large early mammals of the neo-Triassic? That is one of prehistory's greatest mystery. Was there a second renaissance of evolution that gives credence to the theory of stratified evolution? That theory simply asserts that a prehistoric-like environment will engender another round of prehistoric creatures. Sounds like science fiction, but consider the ancient-looking lizards of the Galapagos Islands. Or do the skeletons of animals that evolved continuously from the early Permian to the neo-Triassic exist somewhere? Is such evidence simply undiscovered? Of course Dimetrodon phased off or became extinct as some would put it. A popular theory is that Dimetrodon evolved into an early mammal-like animal called a therapsid.  Therapsids in turn gave rise to mammals. But did some of Dimentrodon's elitist characteristics transition into more advanced lizards of a large size. No proof yet, but did somewhere along the line crocs and gators, without any temperature-regulating sail, clinch their survival and presence inside tropical or semitropical swamps and rivers. In other words those animals that controlled the the number of amphibia no longer had to roam from swamp to swamp. They became resident regulators of amphibians. Did the world's greatest volcanic and CO2 extinction trigger the greatest occurrence of stratified evolution that re-engendered the continuation of basic species? No one knows if during very warm Periods a persevering Dimetrodon continued to make its rounds. But surely Dimetrodon was an important evolutionary figure during the early Permian. And because of excessive heat, roaming coldblooded animals could have utilized a temperature regulating sail during the Cretaceous. After all there is an early Cretaceous sailed theropod somewhere.  Dimetrodon is believed to have gone extinct at the close of the Permian Period. Apparently, the control of numbers became an in-swamp occupation and crocs and gators, while exchanging genes, roamed during cloudy weather. But then again there was a great dimming during the early Triassic that may have actually blocked a lot of sunlight, reducing the temperature to a comfortable seventy degrees out of the shade. And Dimetrodon was out of a job, but not forgotten.

Dimetrodon (Edward Drinker Cope 1878) 

For some reason Dimetrodon has joined the ranks of dinosaurs and has become the most popular tetrapod of the early Permian. Dimetrodon was a large lizard and not a dinosaur. Its presence in the El Pueblo early Permian swampsite of northeastern New Mexico predated Tyrannosaurs Rex by over eighty million years. Nonetheless, most people have decided that Dimetrodon stands out from the rest of the early Permian tetrapods. Perhaps it's the showy sail that helped regulate its temperature. That plus the fact that dimetrodon was the main carnivore of the early Permian. He was just a lizard, some may say, but look at its primordial place in time and space. The variable temperature of the early Permian tested the toughest of the cold-blooded creatures. It is possible that lesser creatures curled up and died in the sweltering sun. During extreme hot weather, which was the sum total of a tropical latitude and "global warming" from carbon-spewing volcanoes, Dimetrodon had to keep going, literally. Luckily new research points to nearby seas and rainfall practically on a daily basis even if the evaporation rate was quite high. Dimetrodon was a carnivorous predator assigned by nature to that never-faraway mechanism of which we all partake: the food chain. Dimetrodon was a reptilian who depended on his temperature-regulating sail as he traveled from swamp to swamp mandated with the task of regulating the numbers of infantile hatchlings. It is quite probable that occasionally he regulated the numbers of the propagators too. Dimetrodon was the coyote of the early Permian and the amphibians, and occasionally small errant reptilians, were the rabbits. The absence of Dimetrodon at the top of the food chain would have resulted in a catastrophic overpopulation of amphibians to the point of overcrowding swamps, which often became shallow during the long droughts of the early Permian Period. Conversely, those amphibian tetrapods that reproduced the most, usually the swamp-bound mid-size amphibians, ensured, through sheer numbers, that some of their hatchlings would survive to adulthood. Many amphibians were hatched simply to become food for Dimetrodon. But Dimetrodon had his own problems to content with. Where there is food there is competition. The superfluous numbers of small amphibians were the mainstay for the megafauna (larger carnivores). It is very likely that while competing for feeding grounds Dimetrodon got into regular frays not just with very large amphibians but with other Dimetrodons. A large predator's demise normally entails old age, at which point it is chased away from feeding grounds by stronger and younger predators. An aging Dimetrodon probably became a shore scavenger. 
      So how can we be sure that Dimetrodon, both the male and the female, were predator hunters? The evidence from the following trace fossils provides a convincing feeding profile of Dimetrodon. Except for the infantile Dimetrodon footprint, the other redbed fossils were excavated from a fifteen-feet-square area. They demonstrate that at that particular area a Dimetrodon was doing what it did best: invading a variable-shore hatchery zone full of newly hatched amphibians. But was Dimetrodon going for the tiny amphibians or for the moms? Probably for both if the mom was not too large? But never fear. Newly hatched amphibians depended on microfauna including both zooplankton and phytoplankton and many survived to adulthood without the mother. Many young amphibians were passive feeders.  The name Dimetrodon literally means two measures of teeth, and that in itself proves two measures of prey.

Above photo: One of the best Dimetrodon pes footprints ever found in the El Pueblo swamp facies is that of Dimetrodon berea (Tilton 1931).  Size of all adult-size Dimetrodon footprints so far found in the El Pueblo facies is around five-and-a-half inches long. Above footprint shows bifurcated claw ends which were blade-like at the bottom for added traction. 

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Dimetrodon infantile footprint,
about one inch long

Geological Location and Context of the 

El Pueblo early Permian Swamp Facies

The El Pueblo early Permian swamp facies is located in northeastern New Mexico, USA. It was discovered in 1984 by owner Henry Ortiz during the excavation for salable flagstone. The site is part of the Sangre de Cristo Formation and is early Artinskian, or about 285 million years old. The site was a fluvial environment within a trajectory of contained flooding. The containment occurred within a string of stepped swamps leading from the upland along an intermediate slope. Trace fossils have been confirmed along the intermediate trajectory and at the alluvial-clay valley. Parts of the alluvial-clay valley became the path of the present Upper Pecos River. The El Pueblo facies has so far produced the largest number of Dimetrodon footprints and the largest ichnotype count in the world, including the first ever footprints of that most famous amphibian, Eryops.

Planned Excavation

A backhoe strip is planned for the El Pueblo facies. The above diagram revised from the booklet on the El Pueblo early Permian swamp shows the approximate site of the dig. Although this area had been stripped of overburden since the 80’s a subsidence of the trace-bearing formation and a presence of calcium carbonate “clay” remains a point of curiosity. This excavation will hopefully answer whether the collapse of the formation occurred through intra-bog subsidence or through collapse from later erosion. The carbonate deposit could mean that a low area from progressive subsidence aggraded from closely repetitive flood-evaporation cycles. More details later.

Results of small strip excavation and hand quarrying (late 2019-early 2020):

Each footprint four inches across

Footprint 3/4 inches across, bipedal? 

The planned Excavation, which involved initial overburden stripping, some lower-level stripping and four feet of hand quarrying, revealed ancient collapse of initial strata due to subsidence. A remarkable discovery of an islet and three and four-digit footprints emerged in a very muddy environment populated by quillwort plants. A discovery of a previously unknown stratification process also came to light, which explains previously uninterpreted stratigraphic phenomena. The process defies commonly assumed principles of geology. Look and you shall find. Some of the details, less the newly discovered process of stratification, will be available later in a booklet entitled Investigating a Tiny Islet of the El Pueblo Early Permian Swamp Facies, by Henry Ortiz, 2020. The early Permian, domineered by the world's greatest stages of tectonic and surficial thrust, continues to hide many interesting geological secrets. The new dig also netted, on large slabs, hundreds of bottom gauging footprints of swimming Batrachichnus plainvillensis (Woodworth 1900),  an ichnotaxon that was obviously very numerous and prevalent during the Artinskian early Permian. Based on recent trace-fossil finds, the geologic age of the El Pueblo swamp continues to move closer to the end of the Carboniferous Period. Because of that grey time span from first uplifts to the cessation of all inland marine lakes the approximation of 285 million years ago will remain the same. Like box joints in carpentry, an interlacing of both end-Carboniferous and early Permian environments existed for many millions of years before all classic marine environments in the area finally perished.      

Dimetrodon's Footprints  

Several skeletons of Dimetrodon have been found across the Permian landscape of the United States.  A few skeletons, mostly partial, have been found in New Mexico. Dimetrodon's footprints are much more common, although they are rare in comparison to other footprints of the early Permian. In early Permian swamp trajectories the footprints of small amphibians are the most common. That's because, as numbers go, microfauna (plankton) was the most populous, followed by macrofauna (small amphibians, insects, etc.) and then by megafauna (larger tetrapods). Dimetrodon was part of the megafauna of the El Pueblo early Permian Swamp. The El Pueblo early Permian Swamp facies has produced a modest count of well-defined Dimetrodon footprints, yet probably the most in the entire world. Because no skeletal evidence of Dimetrodon has been discovered in the the El Pueblo facies the local name referring to the trackmaker is IchnoDimetrodon elPueblus. Please note that the El Pueblo early Permian swamp facies is composed of both redbeds and "whitebeds", producing Dimetrodon footprints of both colors. All footprints pictured here belong to IchnoDimetrodon elPueblus (Henry Ortiz 2017) as ichnogenus. Recently found Dimetrodon footprints now confirm the existence of another Dimetrodon type dwelling in the El Pueblo early Permian swamp and related flowways. The second type was none other than Dimetrodon berea (Tilton, 1931). Footprints of Dimetrodon berea elPueblus are shown in the blog, Exceptional Early Permian Footprints. Pes footprints of Dimetrodon berea exhibit bifurcate claws, while the pes of Dimetrodon elPueblus exhibits pointed claws. It appears that these two Dimetrodons and their arch rival Eryops (now evidence of a small Gorgonops has been discovered) were important figures in the protoplasmic scheme of evolution that led to the dawn of first dinosaurs. The actual tetrapodic link or links that evolved into the first dinosaurs remain in question, although early crocodilians are a good guess.

Dimetrodon Was a Narrow Animal

Above photos: Two of the most elucidating Dimetrodon footprints that have been quarried in the El Pueblo swamp facies. Dimetrodon was a narrow animal with a temperature regulating sail on its back. Crosswinds were not favorable for Dimetrodon. Whether its sail could flex with wind, more or less like a fish fin, remains debatable. The early Permian was often windy and Dimetrodon had an important physiological trick up its sleeve. Besides favoring the wind Dimetrodon possessed very wide claw spreads for side balance. The first photo above shows a manus claw spread far wider than the manus width (plantar region). Dimetrodon's peculiar indention of the three outer phalanges becomes self-explanatory: The feet exerted more pressure at the outer phalanges in order to maximize side balance. The second photo shows a complete pes footprint of Dimetrodon elPueblus with a wide claw spread positioned outwardly. 

  
Above photo: Why Dimetrodon's manus plantar lobes (left side, right before the beginning of the digits) sank into the mud remains a mystery. The digits usually remained above the mud and did not record, except for the claw ends. It may be assumed that walking on the front plantar aspect was purposeful, perhaps as a way of anchoring, since Dimetrodon's temperature sail was prone to the strong winds of the early Permian. Whatever the reason, several of these types of fossils have been quarried in the El Pueblo facies. The other footprint (right side) is another functional aspect of Dimetrodon's wonderful foot--which was fit for the mud. The fact that the digits recorded, but not the lobes, means that pressure was applied to the claws and digits in order to "hoist" the plantar region from the mud. 

 Could This be One of the Best Trace Fossils Ever?

This trace fossil was accidentally found at the El Pueblo ichnotelmafacies (swamp facies). This fossil simply recorded the pes footprint of Dimetrodon berea atop the impression of a baby Dimetrodon. The baby Dimetrodon might have already been dead when stepped upon. Then again (tragically) there is nothing unusual about wildlife stepping on tiny offspring. Obviously the El Pueblo swamp was full of a large diversity of wildlife but only under weight pressure would an individual animal leave a body impression.  

  IchnoDimetrodon ElPueblus's Age and Size

Because the El Pueblo early Permian swamp facies is of Artinskian age, the smaller sized IchnoDimetrodon El Pueblus (Henry Ortiz 2017) fits that particular age designation. Larger Dimetrodons that have been identified are probably of Guadalupian Age (later-age) sites.

Age correlation for IchnoDimetrodon El Pueblus is as follows:  A partial skeleton of Dimetrodon occidentalis (Berman 1977) was found in the Abo Formation of central New Mexico. Dimetrodon occidentalis, meaning western Dimetrodon, is closely related to Dimetrodon Milleri (Romer 1937). The relationship is based on a smaller size, perhaps 75 pounds maximum, and on the fact that both Dimetrodons ate small animals. It is possible that those sites representing the above Dimetrodon species are also of Artinskian Age. Sites containing skeletal remains are obviously superlative, yet hard to date because of a lack of correlative ichnological traces. It is most interesting that during Artinskian times, as confirmed by very large footprints, it was ichnoEryops El Pueblus (amphibian) that was the real heavy weight, much bigger than the ichnoDimetrodons and the ichnoEdaphosaurus (herbivore) of the El Pueblo early Permian swamp (Henry Ortiz, 2018). (Please note that as size goes, the newly found traces of ichnoGorgonops indicate a carnivore tetrapod possibly bigger than ichnoEdaphodaurus and ichnoEryops, the aforementioned possibly among Gorgonop's prey. Whether Dimetrodon's sail served to discourage top-mount attackers such as ichnoGorgonops elPueblus is now a point to ponder. Read more about ichnoGorgonops elPueblus in the blog, Exceptional early Permian footprints.) 

Other Dimetrodon Footprints 

from the EPEPSF

Several of the Dimetrodon footprints below have sold on E bay.  Although not a moneymaker by any means, proceeds from fossil sales have payed for travel and other expenses related to the investigation of the the El Pueblo early Permian site. The real reward has been in the discovery of so many different types of footprints that prove a coeval existence of a very diverse fauna within a definitive ecology and environment.   

5-1/2 inch long, recorded in soft mud 

3-1/2 inches, recorded over hard mud

Dimetrodon convex pes footprint
with typical wide claw spread.

Typical five-inch long pes footprint of
 ichnoDimetrodon El Pueblus

Dimetrodon concave footprint
 4-1/2 inches long.

Convex counterpart of above
footprint. Note thick padding.

This is probably a manus

                                 

Dimetrodon pes, five inches long

The above footprint, with a rather shallow and flat indentation, is special. It recorded in an intermittent marsh, on mud, but atop a concreted slab. The chance of finding this type of trace recording is extremely rare. I found it by accident. Since this is a left-side concave (true animal contact impression) an important podological characteristic becomes clear: Dimetrodon usually oriented its claws outward in order to achieve better side balance. Dimetrodon footprints exhibit very good control of the claws and of the metacarpal joints. Some footprints show a sinking of the manus plantar region into the mud and the hoisting of same through downward pressure of the claws.   

Above photo: A Dimetrodon convex pes footprint missing two claw-tip impressions, but still the best available. The EPEPSF is the only site known that produces full-plantar impressions of the Dimetrodon pes and manus. Unfortunately, a lengthy and well defined trackway of the local celebrity, IchnoDimetrodon ElPueblus, has not been found. Dimetrodon's footprints are a bit evasive. Only muddy tracks have been found just about everywhere else.

Convex manus and pes footprint
of Dimetrodon EP.

Above: Hundreds of traces of newly hatched amphibians from the same redbed hatchery zone where Dimetrodon's footprints were discovered. Hatchery zones of the early Permian were endowed with special geological characteristics (geological and hydrological thesis, Henry Ortiz, 2013-2017).

Above: In relationship to its size of footprints and gait ichnoDimetrodon El Pueblus was a narrow tetrapod. It was bad enough that Dimetrodon had a high sail which could catch the wind and compromise its balance. Dimetrodon's pace distance on the above partial trackway was merely four inches (directly between left and right footprints). Its stride (distance between same-side footprints) was eighteen inches. According to its pace angulation, which figures out to about 130 degrees, Dimetrodon did not wait until the mid-Permian for a higher postural pace and gait. Dimetrodon was not exactly a side-limbed sprawling tetrapod that waddled in low water like swamp-bound macro-amphibians. Dimetrodon's relatively tall stature enabled it to wade in deeper water. Its side balance depended much on its wide claw spread and on claws that were oriented to the sides. An important unknown remains unanswered: Was Dimetrodon able to assume a more sprawled walking position when the need arose? That would have made Dimetrodon quite a versatile ambulator, able to submerge in shallow water, and on par for the attack or for the ambush.

A Dimetrodon footprint showing
claw spread oriented outwardly. 

The convex fossil below portrays a Dimetrodon pes and manus in a muddy substrate containing wet slippery mud. Although it is impossible to know if the two ichno-types were interacting the large claw-marks speak volumes: The wide scrapes of curved claws might belong to Ichniotherium cottae. The large claw spread dwarfs the claw-end dimples left by the Dimetrodon. A dangerous situation for Dimetrodon indeed, based both on the large size of some tetrapods and on the fact that Dimetrodon was not welcome in any swamp because of its instinct to feed on small-size offspring.  

Possible interactive traces of Dimetrodon
and Ichniotherium cottae.

The Case of the Dimetropus
(Romer and Price 1940)

The ichno-classification term Dimetropus simply means two measures of feet and initially referred to the Dimetrodon pes-manus configuration. The pes in Dimetrodon is more elongated than the manus. The implications of such a configuration are many. Canines and felines tend to hunch down or to rear on their hind feet only during confrontation or acrobatic movement. A bear, on the other hand, can assume a sustained standing posture while scouting or in anticipation of confrontation. When it came to the lizards of primordia the elongated pes served more or less the same purpose. Rearing on the hind feet gave Dimetrodon and other large lizards a bigger appearance in the face of danger, and of course, the tail added back support and ballast to such a stance. In its quest for savory seed fruits the herbivore Ichniotherium cottae also reared on its hind feet, but its hind feet were not that long. The plantar region was rather short. Ichniotherium cottae probably braced itself on the same large ferns from where it was eating, a stance that a canine or feline will use to reach food that is located atop an object. The more modern implication of elongated hind feet is of course, that of mankind, who in the long run, eventually assumed a permanent standing and walking posture. Thus the Dimetropus classification is quite useful, as it separates early carnivore reptilians capable of rearing on their hind feet from those more inclined to  keeping a low profile. Early herbivores were essentially well-camouflaged foragers that maintained a low profile. Their pedes did not resemble those of a human. Many carnivore reptilians possessed a human-like pes. It can then be assumed that a bear, as well as a human, is a modern Dimetropus in many respects. 

Above photo: Please note that this footprint has been revised as belonging to Gorgonops and is now included in the blog Exceptional early Permian Footprints. It takes a while for my sub-conscience to latch on to the vibrations from the past. See and listen and be guided, as the sage wanderers of yore used to say.  I should heed the advise. 

Collectors Beware

Above photo: Infantile Dimetrodon swimming footprints in shallow water (half swimming, half walking) with pes ahead of manus because of momentary swimming suspension. Please note that the best way to identify a Dimetrodon footprint is by the human-like or bear-like appearance of the pes. The manus is roundish and can have four or five visible digits. Five digits is standard on both the pes and the manus. The pes footprint is usually located close behind the manus footprint. Infantile Dimetrodon footprints (above photo) also have this configuration. Everyone likes Dimetrodon. Occasionally small amphibious salamandroid footprints, of which there are many, are sold as infantile or small-type Dimetrodon footprints. No similarity to real Dimetrodon footprints whatsoever. The Dimetrodon footprints are of the Dimetropus classification type (two measures of feet). When in doubt simply google Dimetrodon footprints.

Other Interesting Footprints From the El Pueblo 
Early Permian Swamp Facies

( Please note that the following are not Dimetrodon footprints)

This footprint was recently discovered in the El Pueblo swamp facies. It appears to be four digit in respect to the four claws and the plantar region is broad and less articulated than that of Dimetrodon. The wide claw- spread nonetheless suggests a reptilian that traveled on both muddy swamp shores and on dry land. Perhaps another similar find will clarify this one.

Possible interactive traces between infantile Ichniotherium cottae and (fleeing) centipede.  Not to worry, Ichniotherium cottae was an herbivore. Adult Ichniotherium cottaes spent a lot of time feeding inside swamps and protecting their young. Traces lacking in one area and very apparent in another often indicate hard-moist and soft-moist surfaces respectively.

Above photo: Dimetropus isp. (Romer and Price 1940) appears to have possessed very slender digits.  This would mean that it was a light-weight tetrapod or that its feet were webbed. Nonetheless, the footprint of Dimetropus, meaning five digits on each foot, cuts an impressive figure in some ichnofacies of the Southwest, including in the El Pueblo early Permian swamp facies. This Dimetropus footprint, if it is that, appears to be a manus with a modest slip-and-slide context. The pes apparently did not indent into the manus impression, again suggesting a light-weight tetrapod. More impressions are needed to fully assess and confirm these impressions.

Footprint Showing Pes Plantar Region

Above photo shows a deeply indented pes footprint of the amphibian Tambachichnium (Mueller, 1954). Tambachichnium does not appear in the El Pueblo facies in any large infantile ichno-count, posing the possibility of a reptilian entity. Whatever the case may be, Tambachichnium, first discovered in the Tambach region of Germany, left many side-by-side pes footprints in the El Pueblo facies suggesting a penchant for standing on its hind feet. No doubt, Tambachichnium was an Interesting tetrapod of the early Permian. 

An Interesting Partial Trackway

Above photo: These tetrapod footprints exhibit slight sideways curvature of the claws. The claws were a bit long and extend from a rather round and short plantar region. The three claw marks at left-top of photo are from a different footprint.  Footprint at far left shows very short digits. The unusual physiology here is a roundish plantar region with very long claws, noticeable on top middle footprint. This was probably a very mobile mud-sink resistant tetrapod about the size of a large house cat. Note digit traction lobes (these are underfoot tracks) that kept the claws elevated on hard ground (from Paleonychiological assessment notes, Henry Ortiz, 2014-2017).

The above footprint is that of Tambachichnium. Its discovery in various partial indentations, and now with long curved claws, has sometimes resulted in erroneous identifications. Different specie of same genus also continues to confuse identifications because the variety  of early Permian ichnotypes is very extensive. This footprint is three inches from one outer digit to the other, or at widest point. Long side-curved claws, as in many Dromopus species had a certain degree of swivel that allowed turning the claws downward in deep mud and sideways on harder ground. Stepping on side-placed curved claws atop concreting swamp surfaces minimized pressure on the phalanges. (Updated identification by H. Ortiz, 5/2019).  

Above photo: Is this footprint what it appears to be, an early Permian  footprint of a neophyte dinosaur?  Not enough evidence to draw any conclusions yet, although according to the main principle of nychiology a tri-digit dinosaur-like footprint of the early Permian would not come as a surprise. Nychiology focuses on the appropriateness of claws as well as the supporting digits and phalanges in relation to the environment and ecology. The early Permian was a muddy affair. It was demonstrated in later geological Periods that for those animals that had achieved a higher mobility the tri-digit physiology proved the best for overall balance in a bipedal stance, and also the best configuration for avoiding too much adhesion to mud. In a tri-digit configuration the inherent space between the digits and claws allowed the quick shedding of mud. This same principle apples to birds, ancient and modern. The added weight of mud stuck to a bird or bipedal dinosaur's feet would have been crippling.

A muddy affair: Above photo shows an indeterminate set of a pes and manus. The pes and the manus are quite similar. The track-maker obviously walked in deep mud, judging by the broad soles and digits. An inward digit curvature is suggestive of Ichniotherium cottae. The inwardly curved claw imprints are probably there, except smoothed over by deep mud.   

Above photo shows the concave right-side pes footprint of Erpetopus willinstoni (Moodie, 1929). Note sizable plantar region and outer thumb impression. This footprint had been attributed to the late early Permian, but fits right in with the early Permian (Artinskian) designation, or about 285 million years ago. The El Pueblo swamp facies again exemplifies the universality and great diversity of early Permian ichnotypes. Because this same ichnotype has been found in Europe the parameters of Pangeaic biosynchronicity remain irrefutable. The only slight chronological differences would be those imposed by variable climate zones, as a tropical belt of the same latitude could not have existed and persisted across pangea without minute gradations of coevality due to slight and uneven continental travel, dwell and spin. In other words the biological early Permian of one continent can be slightly earlier or later than the early Permian of another continent. Climate and geological environments, inclusive of intercontinental-induced uplifts, were the determinants of any specific progression of biological evolution (research notes and comments, Henry Ortiz, 2017). Footprint measures about four inches in length and is probably adult size. One of the most important concerns in paleoichnology should be the co-identification of both the adult and infantile size of footprints whenever possible. By nature, early Permian sites present a high ratio of infantile-size footprints sometimes resulting in suppositions of adult size. 

Above photo shows one of my earliest discovery fossils from the El Pueblo early Permian facies. I have thrown many guesses at these traces which appear to be of a sideways-ambulation context. My best guess is that these are the sideways travel traces of a mud-skipper fish being coaxed along by a watery slope. The circular indentations represent the bottom lobe-like fins and the small oval impressions at bottom of photo represent the tip of the tail. Top of swirls to bottom of oval impressions measures four inches. This means this mud-skipper fish was about six inches long. There were many estuary-like environments during the early Permian, usually at points where abundant floodwater was entering swamps and lakes. This is a floundering fish-fin fossil.

Above photo shows swimming-fish fin traces (undichna, from undulating path) possibly of the pelvic, anal and caudal fin. Swimming trace-way is about four inches long, probably made by a small fish brought down from the upland by flood water. This fossil was quarried from the drainage side of the El Pueblo swamp facies, one of Dimetrodon's hunting spots. Carnivorous tetrapods migrating from the upland eventually increased fish survival in upland lakes. Fish survival in lower swamps that were occupied or visited by many predators was probably not too viable. Although upland creeks and lakes experienced influxes of large rocks, most fishes survived that danger as they still do, by swimming close to the surface or to the sides of strong currents that roll large rocks. This is a swimming fish-fin trace fossil. Henry Ortiz, 2018.

   

Above photo: Probable footprint of Gilmoreichnus hermitanus (Gilmore 1927). Much bigger than previously found.

Above photo: Footprints of Nanopus caudatus, meaning small footprints with occasional tail drag impression (Marsh 1894). Nanopus, whose footprints are quite common in the El Pueblo swamp facies, was probably a swamp-bound salamander-like amphibian.

Above photo: So how big was Hyloidichnus bifurcatus (Gilmore 1927)? Above partial trackway shows Hyloidichnus taking nine-inch footsteps, just like a forty pound dog. In its sprawled long-tailed nature this Hyloidichnus track-maker was probably four feet long. Many early Permian lizards walked tall but were able to assume a sprawled stance for submergence or refuge in shallow water. Hyloidichnus was probably one of them.

Plants from the Time of Dimetrodon

The El Pueblo early Permian swampfacies has produced the traces of many plants that existed within or at the immediate perimeters of the swamp. The following is a sampling.

Above photo: Convex trace of a kelp plant flattened by flood current and buried in clay. Kelp plants were an important source of iodine essential to the evolution of locomotion in early animals. Plant impression is about four inches wide.

Above photo: Traces of lycophyte plants flattened by water and sediment ingress. These were swamp-shore plants. Larger impression is about one inch wide.

Above photo shows a concave impression of the top part of a multi-bulb water-storing plant, possibly Lesqueria elocata that held a scaled stem and follicles at top. The fact that this plant impression recorded on redbeds suggests a tough outer layer. Lesqueria elocata was first discovered in a Cretaceous exposure (Dilcher and Crane, 1985). Trace is about 3-1/2 inches across. One of the most significant attributes of the El Pueblo swampfacies is the yielding of both faunal and floric traces that were previously assigned to a previous or to a more recent geological period.  

Photo above exhibits a convex impression of a small cycad trunk or barrel with that most famous cover from the dim past, scales. Cycads  were very important land plants that stored water for use during dry periods much like their contemporaries and modern barrel cactus do. Cycads of the early Permian may have possessed edible parts. This was a smaller plant probably transferred by floodwater after uprooting or desiccation. Trunk trace is about 2-1/2 inches across at widest point.  

The above trace is a 285 million-year-old fossil conifer-mat. The bottom of fossil is about six inches across. It is colorized from the original red-bed fossil found below the El Pueblo early Permian swampsite. It is probably Walchia conifer and other finer evergreen sprigs and shreds brought in by flooding in same area. 

Above photo shows the top part of an unusual plant that appears in the El Pueblo early Permian swamp facies. The unusual quality of this plant were the leaves, which were thick and apparently stored water. The fact that this is a resistant plant that has recorded the form of its bulbous leaves can only mean one thing: This was the rubber plant of the early Permian. More photos of this type of plant will be shown as they become available. 

An Indication of Abundant Flora 
and Plankton

Above photo: That thin layer peeling off on left side is the standard clay layer that allowed accessibility to trace fossils of the El Pueblo early Permian swamp facies. But some of the clay layers contain a chlorophyllic tint of green from finely milled vegetative matter that was suspended in water. Undoubtedly this suspension included the primary food source that made it all possible: the phytoplankton that supported zooplankton, both which supported amphibious life, which in turn supported reptilian life. This greenish layer is modernly apparent in some ponds and other fertile water containments of decreasing water supply such as vegetated earth livestock tanks and small lakes. Perhaps the early Permian was even more fertile than the present. Microscopic examination shows the components of the clay but not any discernible micro-components from vegetative matter. 

Above: A freshly quarried slab with chlorophyllic tint. Smaller footprints are from Dromopus sp., large indentations at bottom of photo are Ichniotherium cottae ambulative claw marks.  Vegetation transferred into the swamp by strong water currents was Ichniotherium cottae's delight. As effective controllers of vegetation Ichniotherium cottae and Edaphosaurus would have logically fed on spore cases and other fruit appendages.  

Photo above shows a colorized version of preceding fossil that attempts to restore what the surface looked like at the time these footprints were created. Note concave raindrop impressions (may appear convex on photo) that confirm that this surface was moist but above water. 

So What About Early Permian 

Weather Events?

Called Paleotempestology the early Permian and other Periods got their share of significant weather events. Dimetrodon, with a tall sail to reckon with, along with the large assembly of early Permian lizards, large and small, were occasionally subjected to very rough weather ranging from large hail to intense rainfall and powerful winds. Even if intense rain and winds served to convey insects, spores and flood-displaced lizards (tetrapods) further down the swamp valleys, some of these weather events probably resulted in injury and even death. In respect to modern catastrophic weather events the underlying natural origins and causes of such events remain the unquestionable catalysts of which nature gives little warning, explanation or apology. 

Above photo: During the existence of the El Pueblo early Permian swamp a single layer in particular relates to an unusual weather event. The context of this trace fossil, categorized as a weather dynamic fossil, is wind. The wind came from the present southwest side of Pangea, which was close to the equator. The wind was powerful enough to erase any previous impressions and scored the wet mud with what are probable sand or dirt particles (or flat rain?) blowing over the swamp. The marks along the bottom of photo are from an unknown object being blown along the surface. There are two possible explanations: There are no raindrop impressions because it might have been a dry wind or, more probable, the water was pushed toward the middle of the swamp and then spread evenly again when the wind gust abated, blocking any traces. Either way, wind scoring over a semi-hard clayey surface points to wind of substantial force, such as from a micro burst or even from a hurricane that had lost wind speed over land. This fossil might represent an early Permian hurricane that had abated into a tropical storm. 

The Age of Lizards

The early Permian is seldom described as the age of lizards. Yet countless footprints of the late Paleozoic and other Periods include the words saur and lacerta. The Paleontologists of yesteryear were quick to recognize a world barely separated from fishes that had converted to "long sinuous walking animals" as their fins transformed into feet.  

From the Prey Side   

Above photo: This sixteen-inch long trackway exhibits about thirty very small footprints. The manus was barely 3/8-of-an-inch long. Infantile or adult? Hard to tell. What is apparent is the small size and the susceptibility to predation, especially if not in the refuge of water and aquatic vegetation. Such was paleo-predation in brevity; an often short-lived existence that in many species prompted the propagation of large numbers in order to insure the survival of a few. If we consider that the common toad is actually poisonous to predators then we can infer that in nature everything fights back, somehow, in some way. Many so-called swamp prey or captive prey, then and now, has become toxic or otherwise detrimental in some way for the predator. The trackway above shows very intentional direction. This track maker was probably headed for deeper water or into the swamp itself. 

Burial of The El Pueblo Swamp Facies

At the end of the Permian Period the El Pueblo swamp facies was buried in several hundred feet of sediment. The evolution trajectory, which at the present runs from north to south (as it generally did before), runs in a typical geological-age progression. Twenty miles downriver skeletal remains of mid-Triassic dinosaurs and large amphibians have been discovered, although in a very fragmentary condition. Dinosaurs of the mid-Triassic hint of a great change from the fauna of the early Permian. Although large swamp-bound amphibians were still occupying swamps, dinosaurs were getting bigger, but more importantly, more mobile. Although still small, perhaps in the two hundred pound range, dinosaurs were hunting up and down the upper Pecos alluvial valley, probably from lake to lake and from swamp to swamp. By the end of the Triassic Period the high mobility of early dinosaurs had probably created a crisis of sorts: the cannibalizing of eggs. Newly hatched dinosaurs left unprotected also became prey for large wandering dinosaurs. Dinosaurs had to roam in order to eat, often leaving nests unattended. Even if this served to regulate numbers the smaller animals were having a hard time surviving. A great need for innovation within the mandate of early evolution arose. That innovation occurred in smaller animals that could hide in small spaces while evading early dinosaurs with keen eyesight and a keen sense of smell. Memory genes carry information of traumatic and negative events, and God-particles are forever busy. Besides hiding under rock ledges these small animals may have been tree climbers, and might have even utilized holes in tree bark, just like birds do. If we think opossum or rat then we might be getting close to the entity of the first mammals whose great innovation was live birthing, mammary glands for feeding, and of course, the ability to hide along with their offspring. Rats might have also participated in the plundering of dinosaur eggs. Mammals probably did not get bigger until the world became a safer place, which would mean an environmental expansion that spread dinosaurs into much broader habitats. This in turn would mean that swamps were changing into creeks and streams, and unfortunately, fossilization was becoming a less common phenomena. End-Triassic fossils south of the El Pueblo facies have not been found so far. Like in so many other places, the Upper Pecos valley continues to hide quite well the vestiges of its first mammals. Survival was the name of the game and it was dinosaurs, of the small kind, that created what is probably the greatest innovation of all. In order to escape so many large dinosaur predators smaller dinosaurs took to the trees and eventually learned to fly. The Upper Pecos valley and all of New Mexico, even with its strong fossil record of dinosaurs, is still far away from divulging that fossil of a small  dinosaur with feathers.  

Copyright © 2017 by Henry Ortiz. All rights reserved.

The author reserves the right to make corrections and or to update this blog. Occasionally mistakes occur that unfortunately cannot be blamed on anyone else.  But we keep trying.

Contact e-mail address:   elpuebloearlypermianfacies50@gmail.com

Blogs related to the El Pueblo early Permian swamp facies are free-view in the interest of sharing information with all who are interested in earth's geological history and procession of early life. 

Trace fossils from the El Pueblo early Permian swamp facies are available for purchase at flagstone yard (575-421-7045) and on e-bay under: El Pueblo early Permian. Thanks for viewing.