Python Vestigial Pelvis, Femur and Spur

Questions such as these (Source) raised further questions that only professional herpetologists, geneticists and the like could perhaps ever answer. Those "spurs" that we have seen on the Boa/Python, are they truly "vestigial limbs" ? --or, perhaps they are genuinely "spurs" like those found in the males of birds and monotremes (aka platypus). For now, as far as I am concerned, the jury is out. The "expert" conclusions differ,

"...In the Boinae [Boinae are a subfamily of boas found in Central and South America, Africa and Southeast Asia] the pelvic spurs are modified scales, located either side of the cloacal region and usually comprised of just one scale. They DO NOT APPEAR to be linked to ANY BONE structure and unlike other scales they have a high degree of mobility and can be moved by appropriate musculature from their normal position, lying along and against the body, into a perpendicular plane to resemble miniature legs."
The Role of Pelvic Spurs
Originally Published in HERPTILE (UK), 10 (3), 1985, PAGE 95
(Source)

These structures may in fact be "true spurs" and not "vestigial limbs," because they mostly develop in males and are not connected to any bone structures.

Photo (above) of rooster spur and a python spur. Both are made of the same substance (keratin) and both can or do break off, sometimes, on their own.

BEWARE: THIS IS WHAT THE TOPIC IS ABOUT

Spurs sometimes come off. It is keratin -- that forms a layer around a bony material. The structure in question is not a "vestigial limb".

Concerned Python Owner: "...My ball python just shedded today and I again noticed some blood on the anal spot of her shed. She also had some blood spots in and around her anus. I do not know what is causing it. This is probably the second or third time this has happened." ANSWER FROM A CONCERNED DARWINIST: "...Shed it's spurs? They don't shed their spurs. Their spurs are vestigial limbs...Shedding their spurs would be like a lizard shedding it's back legs." (Source)

The spur (or for those who mistakenly call that exterior keratin structure a "claw") -- is its "leg"? a "femur"? They are mistaken.

CLARIFICATION

The "vestigial remnants" in the python/boa, are not 100% "vestigial leg" as in a "femur"... it is not. Part of the structures, do in fact shed, because it is a spur, similar even to a claw... and NOT a "femur".

Spurs also (to the extent of my knowledge) come symmetrically on each side of the body, in pairs. Claws are located at end of digits. There should be up to five "claws" if they are truly "claws".)

"...Lizards are suppose to have 5 toes, chameleons however have 2 melded toes. 3 toes melded together on one side and 2 on the other. That way they can grasp sticks better."
(Source)

"...Amphibians and birds typically have four digits on each foot, amphibians having lost digit one (thumb) and birds digit five. Reptiles usually have five digits."
(Source)

Claws also shed but are quite different in appearance from spurs. Photo below of "claw sheaths" shed from a cat.

What Causes Claw Sheaths to Fall Off?

The good news is that the process is natural and actually beneficial for a cat. Claws are essential for felines, who use them for defense, climbing and hunting.
According to Dr. Smith, when this happens, the nail has grown beyond the blood supply, so the outside sheath is discarded to make room for a newer, sharper version. He estimates that this happens to each claw about every two to three months in the average housecat.
(Source)

Here is my current understanding. I have added text and arrows to the photo.
I found this otherwise great image, on a Creationist website denying they are limbs. (Source)

I've marked the image with a "?" (Question mark). It is a spur, attached to a vestigial femur and pelvis. Is it attached, or is it free floating? The python vestigial pelvis is free floating, and not attached to bone. This is normal for many rudimentary limb structures.

(Source)

"Skeleton of an Indian Python, showing the tail (left) and ribcage (right). The extra bones attached to the ribs (glued for mounting, but naturally just attached to the flesh without direct contact with any ribs) are half a pelvis and one of the back legs, which pythons and boas have not completely lost. Though they are not the only types of snakes to still have these vestigial legs (appearing as cloacal spurs on live animals), they are the ones that are best known for the feature."

A historical discussion about Python/Boa "Spurs" from The Penny Cyclopaedia of the Society for the Difussion of Useful ..., Volume 5.

Spurs are fused with bone.

Medical Management of the Rooster Spur
"...The radiograph shows the tarsometatarsal bone (A) with the calcar (B) protruding from it. The calcar is surrounded by an extensive horny, keratinized layer (C). The calcar and the horny layer make up the spur." "...The spur papilla can be removed when the rooster is still a chick. A veterinarian uses electrocautery to hinder the growing cells of the spur papilla. Since the bony core is not fully developed, the process is quick, non-invasive, and the bird recovers well. Removing the spur from an adult rooster is a more invasive procedure, because it involves the amputation of bone. The rooster is anesthetized, and a bone saw is used to cut the spur at its base from the tarsometatarsal bone. The skin has to be sutured over the wound and the area needs to be kept clean. Postoperative infection of the bone is a possible complication."
(Source)

A photograph of the python skeleton and the remnant "femur" is deep inside the body of the python the "vestigial pelvis" and spurs are fused with it, and attached at the end. Spurs are fused with bone. They are not "claws" and they are NOT "vestigial femurs"... or whatever people have tried to call them. There is a vestigial pelvis, femur... and SPURS.

Some have attempted to rename these vestigial spurs to "claws" because now, in modern time their only functional purpose seems to be alignment during mating. They're now no longer used to subdue prey or territorial -- therefore "how could they possibly be spurs?" For starters, they're vestigial spurs.

They were spurs. That is evident because they are prominent on males and quite often a trait unique to males (as all spurs tend to be). They may function like a claw but these structures are vestigial spurs. Spurs are determined typically by gender, "claws" are not.

Reports of loss of "spurs" common among Python and Rooster owners:

"...he got in as usual and suddenly started fighting against the mirror on my closet door. As soon as I noticed that I immediately opened the door so that he couldn't see his reflection, but it was too late: he broke his right spur."
//As long as it is only his spur that is injured and not his foot or joint, he should heal just fine I think. My rooster seems to actually pick his spurs off once a year when they get too long and then they just grow back like a toe nail.
///My rooster lost his spurs and they grew back."
(Source)

"...just wondering if anyone's experienced broken spurs with any of there male breeders? I was cleaning cages today, and noticed my male blood python whos been breeding a few females has half spurs..."
///After a shed, or even during the shed cycle, the snake looses its full outter epedermis layer right .. including the rattle on a rattle snake or the outter layer of the spurs on a large boid. I mean, venemous snakes even shed there fangs so I don't think shedding there spurs is that far fetched..
Snakes loose their outter superficial cells in order to renew their skin.. In the shed process the intermediate epidermal zone is full of blood vessels and is seperated by the epidermal zone by a small layer of O2. During this process, the deeper layer keratanizes.. and the sloth comes off.."
///This is normal and nothing to worry about. Sometimes they break off. The spurs are their softest when the snake sheds and if you pinch the nail of the spur you can actually pop it off (and sometimes it doesn't take much to do that)."
(Source)and (Source for Python Spur Photo)

"...The fangs are shed and replaced periodically". TRUE. (Source)

SPUR BREAKS OFF FROM PYTHON AND OWNER CONCERNED:

"...I don't think it's anything to be concerned about. I think they may be equivalent to fingernails and will grow back over time."
"...anyhow the spur are just a build up of dead skin on a toe for lack of a better word ( off the top my head) and can be consider something like a nail. Their no real pressure to remove it and it don't bleed, and the snake O removed it from don't even care."
"...I agree with the fingernail analogy. I've had a ball python get a spur torn off when it got stuck in the fabric of a snake bag. I pulled the snake out and the spur stayed behind. I haven't really paid much attention to it, but if memory serves it is growing back. If there is some root of the scale left behind it should grow back, but if its been torn out completely it may not."
(Source)

Popping adult male python (Source)

Popping adult female python (notice typical reduced spur size) (Source)

Determining Snake Gender (Source)

"...Spurs have a bony core and are covered with a keratinous material similar to our fingernails."
adjective 1. composed of or resembling keratin; horny.
As in a "horn". Not quite the same thing as "bone". It would harm a snake if its "leg bone" broke off, but herp owners seem to feel it is a relatively common occurence.
keratinous in Medicine
keratinous ke·rat·i·nous (kə-rāt'n-əs)
adj. Relating to or resembling keratin.
Horny.
(Source)

This lady is trimming her rooster's spur. It's huge and twists off and does not harm the rooster. Just like python spurs can come off.

"...Scales are formed largely of keratin derived from the epidermis. As the snake grows, which they do their entire lives (growth just slows as they get older), this outer layer of epidermis sheds off. New scales grow beneath the older outer scales. Eventually, the outer layer sheds off, usually in one piece and inverted as if it were a sock pulled from the top down. This shedding process is called ecdysis. They also lack a pectoral girdle (shoulder bones) and — with the exception of the boids, which retain a vestigial pelvis AND EXTERNAL SPURS — they also lack a pelvic girdle (rear leg support)." (Source)

[Why with "Darwinists," does it always have to be (ONE) or (THE OTHER) and not possible to be BOTH? Because very few have acknowledged it was BOTH spur and limb rudiment?]

"...Both boas and pythons have external or cloacal spurs. These sharp, keratin-covered, bony structures are remnants of the vestigial pelvic girdle. Spurs are better developed in males, and are very small or absent in females."
(Source)

If they are true "spurs" found in Pythons, it explains why they develop mostly in males. Therefore they would not be "vestigial leg" remnant which size and distribution is not gender-oriented. See the article at NCSE, which describes enlarged limb remnant in FEMALE whale.

In July 1919, a female Humpback Whale (Megaptera nodosa) with two remarkable protrusions on the ventral side of the body, posteriorly, was captured by a ship operating from the whaling station at Kyuquot, on the west coast of Vancouver Island, British Columbia. One of the protrusions was cut off by the crew of the vessel but the other was photographed in situ by the superintendent of the station.
(Source)

If they are not true "spurs" found in Python, there remains a serious problem to overcome. The growth, acts as a spur and are typical -- primarily found enlarged in males. Which evidence seems to show as gender-oriented, and a spur. For that reason, I have strong doubts about the research being referred to.

"...However, little mentioned is that males of at least some species (or all species?) also possess paracloacal spurs, one on each side of the cloaca (and normally hidden from view by the hindlimbs) [adjacent photo shows paracloacal spur (in box) of Py. schraderi, as revealed by lifting hindlimb. Photo by Henry Cook, from the Aussie pythons & snakes forum]. They look much like the far better known spurs of male boas and pythons. Evidently, the pygopodid ‘spurs’ are nothing to do with the hindlimbs – they’re neomorphs (and they aren’t unique to pygopodids: they also occur in carphodactylid and diplodactylid gekkotans). This got me thinking. It’s widely thought that the cloacal spurs of boas and pythons are relictual hindlimb remnants – but could they actually be neomorphs too, and not genuine hindlimbs? Well, no. Embryological work demonstrates pretty convincingly that the ‘relictual hindlimbs’ of certain modern snakes really are relictual hindlimbs (Cohn & Tickle 1999) (this issue was previously discussed in Monster pythons of the Everglades: Inside Nature’s Giants series 2, part II). On a more speculative note, does the presence of cloacal spurs mean that pygopodids have the evolutionary potential to evolve an extra set of posterior limbs?"
(Source)

Here is the "hindlimb" and "spur" being shown on the page:

True vestigial hind limbs normally are not noted in literature as "larger in males" and/or "absent or reduced in size" in females for purpose of determining gender or gender-based. (However, Source) Gender is seldom noted with limb rudiments, to imply a gender-oriented purpose even, in spite of Answers in Genesis who claims that such structures aid males in copulation among some whales. If a "design" and "purpose" for structures is implied, then who, or what is the female humpback mounting?

Due to the lack of objectivity in both "pseudo-Darwinist" and "Creationists," I won't accept either of their explanations at face-value. Research can be contradictory, depending on which scientist(s) are behind the work. Evidently, other scientists have came to different conclusions. They must explain "why" the limb would manifest -- primarily in males. Why a "limb" (vestigial or otherwise) is not comprised of cartilage or bone) but composed of keratin (like true spurs). If designed specifically for sexual reproduction in males, then WHY place such limbs on females? Just as spurs are typically reduced, and sometimes absent in females.

True Spurs
"...The platypus uses its spur mainly to fight for females during the breeding season. It can also be used as a potentially effective mechanism for males to ensure that they have spatial separation from each other.
Juvenile females have a rudimentary version of the spur, but, unlike juvenile males, they lose it within their first year. The spur of the female does not change in size during the 8 to 10 months it can be seen, after which it is shed."
(Source)

Hartz is a reputable company that deals in pet supplies. It notes among the larger female, the spurs generally are reduced in females -- which seems the opposite holds true for hind limb rudiments in whales. :

Snakes: Visually sexing your snake is tricky, but generally speaking:
The female is larger and more rounded than the male.
In larger species, such as boas and pythons, you may see spurs on either side of the cloacal vent. The spurs will be much larger on a male than on a female; in fact, many females have little or no spurs at all.
The tail of the female also tends to look shorter and wider while the male’s tail is longer and more slender in appearance.
These tips for determining the gender of your reptile are not foolproof - your pet snake might be a female with large spurs or a male with a shorter, rounded tail. In general, it’s best to let your veterinarian or an experienced reptile handler figure it out
These tips for determining the gender of your reptile are not foolproof - your pet snake might be a female with large spurs or a male with a shorter, rounded tail. In general, it’s best to let your veterinarian or an experienced reptile handler figure it out.
(Source)

I present evidence of a FEMALE who grew spurs. True spurs, not "vestigial hind limbs". Females among birds and reptiles can develop spurs, but they tend to be either reduced, or absent. It is a gender-related trait, not a "hind-limb" trait.
If these structures tend to be reduced in females, then it is a spur.
Otherwise, my question would be, "Show me evidence that hind limb rudiments are reduced in female whales and their size increased in males". I will attach the research which explained WHY the female developed large spurs, below :

"TIL that a rooster in Basel, Switzerland was sentenced to burn at the stake for committing the "heinous and unnatural crime of laying an egg". (Source: news.google.com): The Spokesman-Review - Sep 12, 1938
Source: Studies on the Relation of Gonadic Structure to Plumage Characterisation in the Domestic Fowl.--III. The Laying Hen with Cock's Plumage F. A. E. Crew Proceedings of the Royal Society of London. Series B, Containing Papers of a Biological Character Vol. 101, No. 712 (Jul. 1, 1927), pp. 514-518 Published by: The Royal Society

Sex-Change Chicken: Gertie the Hen Becomes Bertie the Cockerel (Under the right circumstances, a hen can actually transform herself into a rooster).
(Source)

At this point, I am nearly convinced the "spurs" on pythons and boas are spurs and not hind limb remnants. Female chickens have spurs, and can become quite large too, due to hormonal imbalances.

"...A spur is a sharp horn-like protrusion that can grow on the legs of chickens, and is used for fighting and self-defense. Although all chickens have the potential to grow spurs, large spurs are most common on roosters. Hens can and sometimes do have large spurs, but generally do not. Spurs on a rooster start out very small and may take a year or more to become sharp."
(Source)
Standard run of the mill, average hen, Gallus gallus domesticus with reduced spur.

Pelvic Spurs Revisited Last week, one reader indicated that some herpetology textbooks refer to the pelvic spurs of some snakes are the remains of vestigial limbs. This is contrary to what I claimed in one of my previous posts ("How Pythons Get It On"), in which I said that pelvic spurs are actually modified scales and are not the remnants of legs. Since then, I have been doing some digging about this topic in an attempt to clear things up. What I found was that there is some debate upon the issue, and more research should be done to determine if pelvic spurs have any relation to legs. I immediately brought the issue up to my herpetology professor here at my university. She had been taught that the pelvic spurs of snakes are related to vestigial legs, and she had never heard anything contrary to this idea. She managed to find a quick reference to pelvic spurs in my textbook, but the mention was brief and provided no analysis. Even though I would trust both of these sources, I also realize that they could be misinformed. I began searching for reasons behind the conflict. It appears that there are two issues at hand here that make the connection between pelvic spurs and legs a bit fuzzy: 1.) Pelvic spurs are not connected to bones. Some use this argument to claim that pelvic spurs are not related to legs. However, I say this means nothing. Just because structures are not connected now, we cannot assume that they were not connected millions of years ago. 2.) Pelvic spurs have much greater mobility than other scales. If you have ever seen a snake move, you will recognize how the skin of the snake will stretch and bend as the snake winds, and the keratinous scales move along with it. The only thing that changes as the snake bends is the spacing between the scales. Pelvic spurs, on the other hand, are quite mobile, and the male will be able to make his pelvic spurs pivot, dig, and tap. In his 1985 article in Herptile, Raymond Hoser questions the assumption that pelvic spurs are related to legs and suggests that they may be "auxiliary sexual organs." Hoser points out that Australian legless lizards also have structures like pelvic spurs, and this is where I thought, "Aha! The lizards that have pelvic spurs are legless! We have our answer!" In fact, we do not. The legless lizards actually do have small legs that are separate structures from the spurs, according to Hoser. This is all really one big mess because I cannot find the original article in Herptile ( I found Hoser at this url: http://www.smuggled.com/pelspu1.htm), nor can I find another reference to both pelvic spurs and vestigial legs in the legless lizards. And, of course, I like to have multiple sources. I realized quickly that this is becoming one large mess that is going to be very difficult to sort out. I would suggest exactly what Hoser recommended in 1985, and that's that we first examine the structure of the legless lizard in more depth. Perhaps legs and pelvic spurs have nothing in common. However, I would also recommend that we look into the exact musculature that is used to move the pelvic spurs because perhaps this could be related to the same muscles used in legs. I believe the most defining evidence found will come from development. If we can look at which genes contribute to the development of the pelvic spurs (and in which patterns these genes are activated), we may be able to determine if pelvic spurs arose from legs. After all, many genes and developmental patterns are shared among species that look nothing alike. Using the same genes (which Sean Carroll refers to as "tool kit genes" in Endless Forms Most Beautiful), many animals follow the same patterns to develop very different structures. I suggest that if the pattern is the same, perhaps the structures are related. In conclusion, it appears that pelvic spurs are generally accepted as vestigial leg remnants among the herpetologist community. Although I now say I do not have the answers, I think the topic should be investigated rather than assumed. Through all of this mess, one thing has been cleared up. In my first post regarding pelvic spurs, I questioned whether female pythons had pelvic spurs. In fact, according to Slip and Shine (1988), females have pelvic spurs, though they are less prominent than the males'. (Source)

The problem... spurs are attached to legs.

Reptile have spurs on leg.
Photos (Scroll down):
young female yemen... showing lack of spur on hind leg..
young male - can see spur
(Source)

And in male platypus (males) the spur is located on limb. So if these two things are so-called "unrelated" it's a sticky question. Maybe the leg disappeared but the spur is all that remains.

Spurs in Geckos... and good photographs. Some species, the spur is ATTACHED TO leg -- and other species the spur is separate.

(Source)

I'm assuming in boa/python early history -- their ancestors had legs with spurs ON the leg. The leg decreased in size, and only the remnant with the spur remains. I am not in doubt the structure is a true "spur" and in many species spurs are attached to legs...
In some species, spurs are separate from the limb. But its safe to presume that was not the case for ancestors of Python and Boas.

One such reptile:

"...Another sex difference of Chamaeleo calyptratus is a Tarsal spur at the hind legs of the males (marked by the red ring). This Tarsal spur is shown right after birth. Therefore, it is possible to differ male and females immediately after their hatch."
(Source)

Concerned Python Owner: "...My ball python just shedded today and I again noticed some blood on the anal spot of her shed. She also had some blood spots in and around her anus. I do not know what is causing it. This is probably the second or third time this has happened." ANSWER FROM A CONCERNED DARWINIST: "...Shed it's spurs? They don't shed their spurs. Their spurs are vestigial limbs...Shedding their spurs would be like a lizard shedding it's back legs." Charles Darwin would blush. What a "fowl vision" -- a "lizard shedding its back legs." What a sweet, beautiful spotted chicken. "The calcar and the extensive horny, keratinized layer make up the spur." So when the "extensive horny, keratinized layer is twisted off," all that is left is the "calcar." And that, after about 24 hours, will just dry up and begin growing again. Like a nail or hair would. Pulling legs off snake. "...According to Tim Bailey (as he's popping the spurs off one of my males), spurs are really just layers upon layers of shed that build up to make the spur larger. They do "grow" back over time with future sheds. He's popping them off my male going "I bet you didn't know that spurs are just layers of shed". And I'm going , my poor boy!!!!! LOL In any case, to the OP - it's no big deal or any detriment to your snake. This same boy went on to successfully father a clutch a few months later with no "visible" spurs. This also further proves that you can't sex a snake based on the size of their spurs." "...I have had my normal boy also break off a spur once in a while. They do grow back slowly, but it is freaky if you've never seen it before!" "...My BP had his left spur come out about 6 months ago and it has definetely grown back some(but not fully) since then." "...I remember reading this somewhere but once a snake loses its spur(s) they will never grow back, and it really won't have any effect on the snake at all. So pretty much once it's gone it's gone. Never mind that, I read the above posts and found out this statement isn't true. Though, I DO remember reading this somewhere." [Yeah, he probably read somewhere that the spurs are "vestigial legs".] (Source)

(2014)
"Although no fossil evidence of these structures has been found, ancestral monotremes likely had venom delivery systems very similar to that of extant monotremes (see Section 3.1), in the form of an extratarsal spur consisting of cornu calcaris (the spur, which is covered by a keratinous sheath) and os calcaris (the supporting bone). Interestingly, there are several fossils of non-monotreme mammals with evidence of a potential venom delivery system similar to that of the monotremes. These include fossils with what have been interpreted as extratarsal spurs [3,13], and fossils with an os calcaris that may have supported an extratarsal spur [14]. It is thus possible that the extant monotreme extratarsal spur is plesiomorphic, having been retained in monotremes but lost in the therians [14,15]. This implies that many early mammals may have had spurs, and possibly associated venom glands, as a defensive mechanism (Figure 1), although additional fossil evidence is required to resolve this."
(Source)

Vestigial limbs rudiments in whales are used for copulation, says "Answers in Genesis." Spurs in male boa also some times, aide in bracing during mating (but is not necessary, example of a breeder confirming the same, cited above). That makes sense. Spurs are generally developed among males. That is not to say that females can not form them due to hormonal imbalances... and that experts warn, that to determine gender, spurs are not reliable 100% of the time. However, most of the time, -- generally -- males have larger (TRUE) spurs.

That is why it is a single SPUR, fused to leg bone, which builds up from dead cells, and can be removed, and on occasion breaks off, naturally.

Since when were "hind limbs" ever used to determine gender? See the reference again at NCSE I have posted:

"...In July 1919, a female Humpback Whale (Megaptera nodosa) with two remarkable protrusions on the ventral side of the body, posteriorly..."

"Enlarged posterior hind limb protrusians" in a female did not help at all in the determination of gender, did it?

Why typically reduced spurs in female boa, other reptiles, the Platypus or many species of birds? But increased hind limb in female Humpback whale?

One is a true spur... the other, is a hind limb.

Claw? Or, Spur?

There are no absolutes. But ask yourself if this in any way resembles "digits" or "claws". Multiple "spurs". Even among breeders this is not considered at all normal.

Normal spurs are in discussion. Not strange genetic mutations, nor are speculative theories about the evolutionary "junk DNA" throwback to the relationship between spurs and claws and how they evolved. That is a topic for another day.

Double/Triple spurs on a rooster
///One leg has two spurs coming up and the other has 3. Had never seen anything like this before him. Had planned in keeping him for breeding and was just out looking at him last week and realized his spurs looked odd. Unfortunately this is what I discovered.
///Well I have to figure the tendency to develop these extra spurs would be inheritable and although it's interesting, it's not something I would want to have in my stock. At least with some breeds that you mentioned at the beginning of this thread, it is known to occur from time to time so it may be accepted in breeding stock. I don't know that for sure in these other breeds but with Swedish flower hens, this is apparently very unusual.///
(Source)

Which Tetrapod in the fossil record ever had "claws" (fingers/toes/digits) attached to their femur? I'm attaching what a "Femur" is -- because visualizing what some are claiming -- is absurd... only SPURS occasionally are attached on some species' femurs.

Try to imagine toes ... phalanges, claws... hanging from an animal's "Femur". Or, as some mistakenly have been taught to believe, when the spur breaks off a Python, it has "broken its leg".

Where did those toes or fingers go to... to leave the claw behind... claws, which attach to fingers or toes. They should be able to X-Ray the "vestigial limb remnant" of the snake and find a couple toes in there... at least a wee bit trace of a couple toes... AND A TIBIA which feet and toes attach to.

Only spurs do this in reptiles... spurs, attached to the femur.

From: "The Turtles of Mexico: Land and Freshwater Forms"

From: Reptiles, Amphibians, and Invertebrates: An Identification and Care Guide
By Patricia Pope Bartlett, Billy Griswold, Richard D. Bartlett

How to determine the correct age and sex of the turtles?

Paws
Inspect and feet. Here are some possible differences:
The boy has a long and curved claws, they need to hold the female during mating. And claws of the female are short and direct.
The male is more developed femoral spurs than the girl.
Males of some species have some scales on the inner sides of the hind legs, which are also necessary to hold the female.
(Source)

To the reader: Look at your body, and then ask, "how many boney "Femurs" do I have protruding through my skin?

My guess is "None". Unless you were in a severe accident such as falling from a 5 story building or a car crash.

... in light of turtle fossils, all the above MAKES SENSE.

This Ancient Creature Shows How the Turtle Got Its Shell
The 240-million-year-old "grandfather turtle" may be part of the evolutionary bridge between lizards and shelled reptiles
"...In addition to illustrating how the turtle's shell evolution likely took place, Pappochelys helps answer another hotly debated question: whether turtles are more closely related to lizards and snakes or to dinosaurs and birds. Based on an examination of Pappochelys’ skull, the researchers now possess evidence that turtles and tortoises fall firmly within the lizard and snake camp." (Source)

This ‘grandfather’ turtle had no shell
The discovery of a 240-million-year-old reptile reveals that turtles and snakes are more closely related than scientists have previously believed, and may help explain how turtles first evolved their shells, according to a study published this week in the journal Nature. The new extinct species, officially named Pappochelys rosinae, was found in a region that was once an ancient lake in southern Germany during the Middle Triassic Period, researchers from the Smithsonian Institute said in a statement. The creature’s physical characteristics revealed that it is “a clear intermediate between two of the earliest known turtles,” they added.
According to Discovery News, Pappochelys rosinae – which has also been affectionately dubbed the “Grandfather turtle” – was discovered by an international team of researchers. Based on its anatomy, the creature has been classified as a “diapsid” (a group also including dinosaurs, birds, pterosaurs, crocodiles, lizards, snakes, and other living and extinct species).
[...]
The study authors also report that this new species of turtle, which is small enough to fit in the palm of a person’s hand, possesses an unusual pair of openings behind the eye socket on either side of the skull. This shows that turtles did not evolve from early stem-reptiles as previously thought, but were more closely related to snakes and other lizards, as modern turtles have lost these eye socket openings. The socket openings can still be found in present-day lizards and crocodilians, however.
“Scientists hypothesize that the development of the shell observed in early turtles supports the idea that the turtle shell evolved in aquatic environments rather than on land,” the Smithsonian said. “Early turtles may have relied on having a partially or fully fused plastron as a defense mechanism against these kinds of attacks. The back portion of the shell, called a carapace, appears later in the fossil record.” (Source)

Grandfather Turtle Had No Shell, But Link to Snakes
"...A newly discovered 240-million-year-old turtle suggests that turtles are more closely related to snakes than anyone ever thought, and it also reveals how turtles first evolved their shells.
"Grandfather turtle," as it has been named, could help to solve longstanding debates about the amazing family tree of all turtles. One theory is that turtles are living dinosaurs, as birds are, but this study, published in Nature, concludes that turtles are more closely related to lizards and snakes." (Source)

As a side note, Darwinists often read "tetrapod" and presume every bit of evolution occurred in "dry terrain" necessitating, land in dry, arid conditions... terms like "Semi-Aquatic" fall on deaf ears, an interesting note in regard to the turtle shell, and snakes who fly, as well as birds:

"...“Scientists hypothesize that the development of the shell observed in early turtles supports the idea that the turtle shell evolved in aquatic environments rather than on land,” the Smithsonian said." (Source)

How many more major evolutionary events occurred because of the underestimated impact aquatic and semi-aquatic environments had on development in various animal anatomy?

MORE MISINFORMATION:

"...The remnants of a pelvis and femur, which have no connection with the spine, simply "float" in the muscle mass.[1] The femur protrudes from the snake's body and is covered by a corneal spur, which resembles a spur or claw.[1] Males' spurs are generally longer and more pointed than females', and are used for clasping and tickling during courtship and mating,[2] as well as combat with other males in some species."
(Wikipedia, Misinformation on "Pelvic Spur").

"The femur protrudes from the snake's body..." ?

Seriously... the femur DOES NOT "protrude from the snake's body."

FACT:

"...snakes both have tiny hips and thighbones BURIED DEEP in their bodies..."

Reference: Evolution: What the Fossils Say and Why It Matters
By Donald R. Prothero
(Source)

The keratinous structure, that is attached to those bones which are BURIED DEEP WITHIN THE FLESH... protrudes on a limited number of snakes... primarily MALES (therefore it is evident the structures are Spurs).

But some persist in the belief, the "Femur" is sticking out of the snake. They really truly believe, a BONE is protruding from the snake and if it breaks off, you have broken a vestigial "limb". It is not a "limb". Though spurs are naturally fused with bone via the calcar.

Biology Quiz 4 U
Name Parts #1 #2 #3 #4 and explain their function.

(Image Source)

BONUS INFORMATION!

Are those the "spurs" laying below the skeleton?!

Spur-Thighed Tortoise Skeleton
(Image Source)

Testudo graeca (Spur-thighed Tortoise) - Female (Source)

Testudo graeca (Spur-thighed Tortoise) - Male (Source)

While reviewing dissections of spur-bearing snakes, I could not help but to notice the close location of the spurs near the scent gland.
The Echidna uses its spurs for secretion gland during mating, whilst the Platypus uses spurs to inject venom. Above is a posted reference to study that suggests ancient ancestors of all mammals likely had spurs with venom delivery system, but they are not certain, yet, until more fossil evidence can confirm it.
There is clearly some primordial relationship between claws, spurs and fangs (they forms keratin sheaths that detach and fall off.) They share the traits of delivering venom or scent (communication)... and associated with mating or defense systems.
I haven't studied this topic in depth, but strongly suspect it. There may be an underlying and closely associated genetic relationship with the endocrine system that govern claws, spurs and fangs and have played a significant role in their evolution. (The endocrine system is the collection of glands that produce hormones that regulate metabolism, growth and development, tissue function, sexual function, reproduction, sleep, and mood, among other things, (Source)) I only found some limited examples of insects as (sometimes) containing venom in their claws, but spurs and fangs deliver venom and spurs sometimes used for scent glands. Other times, they serve no overtly "noticeable" purpose... perhaps surviving as remnants of the past.

Popping Adult Male Ball Python (Source)

I suspect (such as the Echidna) when the male python/boa uses its spurs to scratch on the female, it is a behavior that is linked to the distant past, where the scent gland may have been once involved. In the Platypus, the venom gland is located right behind the knee and connected to the spur. My suspicion is the snake's spur once had a more significant role (with its scent gland so near). I can find nothing significant on the web, that discusses any relationship between the snake's scent gland and the spur. They're in close proximity, but today, separated as far as I know). They do set right next to each other. However, functions, locations, structures alter over time as they evolved.

Cloaca, a common cavity at the end of the digestive tract for the release of both excretory and genital products in vertebrates (except most mammals) and certain invertebrates. Specifically, the cloaca is present in birds, reptiles, amphibians, most fish, and monotremes.

(Image Source)

". . . Many boids possess remnants of rear-legs (femurs) in the form of cloacal spurs that border the sides of the anal plate (and the cloaca, underneath). The post-cloacal scales are divided in this Ball Python (Python regius)."

(Source)

Here is the best photograph of all. The scent gland is located close to the "cloacal spurs" which by definition, cloaca is ". . . a common cavity at the end of the digestive tract for the release of . . . genital products."

Snake Gastrointestinal Tract Anatomy
By Douglas Mader, M.S., DVM, DABVP
". . . In snakes . . .The large intestine ends at the cloaca, a three-chambered structure with multiple functions. Feces is discharged from the large intestine directly into the cloaca’s forward chamber, which is called the coprodeum. The middle chamber, called the urodeum, receives the urogenital (urinary and reproductive) ducts, which carry urine and either eggs (females) or sperm (males). The proctodeum, the posterior chamber, acts as a general collecting (mixing) area for digestive and excretory wastes. The male hemipenes open into the portion of this compartment nearest the tail, and both male and female snakes have scent glands that also open in this location."
(Source)

I can not prove this, but at one time I suspect in the ancestor of snakes, the spur may have served a function related directly to this scent gland, such as in the case of the echidna :

"...Sydney researchers have discovered that male echidnas use the spur on their hind leg to communicate with their peers, quite unlike their close relative, the platypus, who use their leg spur as a weapon.
''The echidna gland looks more like a scent gland, which they use to mark their territory,'' she said.
Male echidnas use the marking to communicate during breeding season but further study would reveal if they were communicating their readiness to mate, or using it to ward off other males.
Professor Belov said the echidna did have some venom genes, with low expression levels, which suggested the animal's secretions may have been toxic and used for defence millions of years ago.
''It suggests they were there in the past and they're no longer important,'' she said.
The gradual disappearance of the venom in the spur secretion meant a new role for the gland had evolved, she said."
(Source).

BUT THAT, IS MERELY MY PERSONAL SUSPICION. . .

Not "Claws" but in fact, "Male Gender (territory, mating, defense) = "True Spurs".

The Role of Pelvic Spurs
"...In all species the mating behaviour is similar. The pelvic spurs are usually held in the "erect" position and used by the male (at least) to stimulate the female. The male at all stages of the mating act has a tendency to dig his pelvic spurs into the female's body. Whilst crawling over the female the male's spurs will scratch the surface of the female snake often making a distinct scratching sound. On other occasions the male's spurs will move rapidly in and out, up and down, again to stimulate the female snake. This supports the theory that the pelvic spurs have a sexual role and refutes any claims that they perform no useful function in modern day Boinae.
Pelvic spurs are, however, not restricted to the Boinae - some Australian legless lizards (Family: Pygopodidae) possess spurs resembling those of the pythons. This is in addition to their rudimentary hind limbs."
This paper first appeared in HERPTILE - JOURNAL OF THE INTERNATIONAL HERPETOLOGICAL SOCIETY IN 1985
(Source)

And, regarding snakes using the spurs to " . . . making a distinct scratching sound . . . " would in itself, serve no function because, by comparing to the way humans perceive the sound of scratching, snakes are for the most part, "deaf"... that is, at least, comparing to how mammals perceive sound, snakes do not "hear" the same way as we do.

They perceive vibrations.

Do Snakes Have Ears?
"...Snakes have no visible ear, so they don't hear sounds as we do. But it's not quite right to say that snakes are deaf. They have vestiges of the apparatus for hearing inside their heads, and that setup is attached to their jaw bones, so they feel vibrations very well and may hear low-frequency airborne sounds."
It's thought that the hissing sound snakes make is purely to warn other creatures, because presumably snakes can't use sound to communicate with each other."
(Source)

Vibrating Skulls Help Snakes Hear
"...In humans, sound waves traveling through the air hit the eardrum, causing the movement of tiny bones and vibrations of tiny hair cells in the inner ear. These vibrations are then translated into nerve impulses that travel to the brain. Snakes have fully formed inner ear structures but no eardrum. Instead, their inner ear is connected directly to their jawbone, which rests on the ground as they slither. Previous studies have shown that vibrations traveling through the ground—such as the footsteps of predators or prey—cause vibrations in a snake's jawbone, relaying a signal to the brain via that inner ear.
It was still unclear, however, whether snakes could hear sounds traveling through the air. So Biologist Christian Christensen of Aarhus University in Denmark took a closer look at one particular type of snake, the ball python (Python regius). Studying them wasn't easy. "You can't train snakes to respond to sounds with certain behaviors, like you might be able to do with mice," says Christensen. Instead, he and his colleagues used electrodes attached to the reptiles' heads to monitor the activity of neurons connecting the snakes' inner ears to their brains. Each time a sound was played through a speaker suspended above the snake's cage, the researchers measured whether the nerve relayed an electrical pulse (the snakes showed no outward response to the sounds). The nerve pulses were strongest, the researchers found, with frequencies between 80 and 160 hertz—around the frequency for the lowest notes of a cello, though not necessarily sounds that snakes encounter often in the wild.
The snakes don't seem to be responding to vibrations that these sounds cause in the ground, since these vibrations were too weak to cause nerve activity when they weren't accompanied by sound in the air, Christensen and his colleagues found. However, when the researchers attached a sensor to the snake's skull, they discovered that the sound waves were causing enough vibration in the bone—directly through the air—for the snakes to sense it. The results appear online today in The Journal of Experimental Biology."
(Source)

(Image Source)

The exception makes the rule (as I stated earlier about there are no "absolutes" (see above reference to a rooster with spur sprouting double or triple spurs --and yardbird breeders finding them to be abnormal)...

Greeks & Leg Spurs
". . . Greek tortoises (Testudo graeca) are also called "Mediterranean Spur-thighed" tortoises. The photo below shows you why! :O) Look at those big spurs (conical tubercles) on that male Golden Greek's legs.
Greek tortoises can have one, two, or even three spurs on each back leg. Both males and females have leg spurs, and they are already present in baby tortoises. One of my adult Golden Greeks has large double spurs while the others have single spurs. . ."

(Image Source)

More turtle spurs. The turtle crowd said "Female". The spurs do look quite reduced. So, maybe that's why.

Sexing med spur thigh

I was wondering if anyone can see if my tortoise is a boy or girl at 4 years old? (Source)

African spurred tortoise (Centrochelys sulcata)
"...Large, overlapping scales cover the front surface of the forelimbs, while the hind surface of the thigh bears two or three large conical spurs, from which the species earns its name (4) (5)."
(Source)

Another great photo of turtle spurs.

(Source)

Closeup view of leg and spurs of African Spur-thighed tortoise. (Source)

Let's Play the "Sex My Tortoise" Game (Source)

. . . a 35 pound adult female for comparison (Source)

/What are two lil bits sticking out near his tale? About an inch away and on opposite side of under belly.
//if they are spurs I've always been lead to believe they are the remains of what used to be a pelvis/femur structure within the snake, generally more associated with heavier snakes like Boas and Pythons. Male spurs are more prominent and larger and are used in the mating process.
///the remains of hind legs!! and males use them for mating!!
////.spurs are like little claws either side of the royals vent...as shown in the pic, they vary greatly in size etc...and have no real bearing on sex, although in other pythons and boas the males often have larger spurs...but in the case of royals it is not a good indicator, I have had females with huge spurs and males with barely visible spurs.

Including owners reporting of the spurs breaking off and grow back, as spurs do.

/////Spurs aren't an accurate way to sex as many royals break the gender rules and have confusing spur lengths.
(Source)

"Keratin Spurs" not a "Bony Femur"

(Source)

Skin
". . . The outer skin on the legs of many chelonians is rough and hard. Some tortoises have armored legs made of keratin to give them even more protection for life on land. The keratin scales can be quite large and create spikes or spurs on the legs of the tortoises. Desert tortoises use the spurs to help retain water.
Aquatic turtle species’ skin is a lot softer with fewer protective scales than that of the land-dwelling tortoise. Although the skin of most chelonians looks extremely rough and leathery, they are very sensitive to touch. Zookeepers have found that many chelonians enjoy having their necks rubbed and will keep going to the keepers for more when they stop."
(Source, American Animal Hospital Association)

So, the question remains, "Vestigial Toe Claw" or "Vestigial Femoral Spur"?

A little comparative anatomy may help.

We have that long "Pelvis" bone labeled as #1...
Some strangely protruding bone structure sticking out is labeled #2...
Bone #3 is clearly a ...FEMUR...
Protrusion #4... Spur...

What #2 is... can give an idea what #3 and #4 are.
Compared to Lizard Leg Bones... the bones match, splendidly.

#2 appears to be nothing more than extension of the pelvic girdle. (As shown with the lizard leg bone diagram).
The remainder are femur and spur...no tibia... no fibula... not even phalanges are present... (which all, in addition to many other bones would all have to have been *skipped* and dissolved?) to jump to a "claw?"

Not likely.
That keratin structure called the "Spur" is a TRUE vestigial Femoral Spur. Not a "toe" claw.

(Source for Lizard Leg Bones Diagram: HIND LIMB SKELETON IN, REPTILE BIRD AND MAMMAL –COMPARATIVE ANATOMY)

Allow me to reiterate.. tibia, fibula, fibular, intermedium, tibiale, centrales, metatarsals, distalia, phalanges... would all have to magically dissolve and disappear... then the femur reconnect to the tip of a single phalange' "claw" and a claw attaches itself to the femur? To presume such a huge evolutionary *skip* in the lizard/snake's leg anatomy, it is questionable... the femur bypasses all those complex bones, and then reconnects itself to a single "claw?"

Highly unlikely..

The simplest explanation is often the correct explanation: IT IS A FEMORAL SPUR REMNANT and a common trait shared between turtles and snakes to this day... down to the tough scales on the inner-thighs of males, used in mating which are noted to form the spurs on some species of both snakes and some species of turtles.

Further Recommended Reading

A whole lot of interesting diagrams, photos, captions and factual overview of Boas...
Boas: Everything about Selection, Care, Nutrition, Diseases, Breeding, and Behavior