A new PeerJ paper by Hone, Henderson, Therrien and Habib (2015) reports on a new complete, articulated (with a crushed and scattered torso) Rhamphorhynchus specimen, TMP 2008.41.001, the Tyrrell specimen (Fig. 1_.
Figure 1. The new Tyrrell specimen of Rhamphorhynchus.
Hone et al report, “Here we follow Bennett (1995) in considering all Solnhofen specimens of Rhamphorhynchus to belong to a single species, R. muensteri.” This is wrong and lazy. Phylogenetic analysis (Fig. 2), which Hone et al do not attempt, divides this genus into several clades. Even the feet have distinct pedal proportions. The Tyrrell specimen nests at the base of the JME SOS 4785 (Darkwing specimen) clade and is similar in size to other clade members.
Figure 2. Cladogram of Rhamphorhynchus. See, they’re not all one species. And phylogenetic miniaturization occurred at the genesis of this genus.
Juveniles and subadults?
Hone et al. report, “The genus has previously been split into a dozen or more species but these have convincingly been shown to consist of juveniles and subadults of a single species (see Bennett, 1995 for a review).” This is also wrong. We know from several single genus bone beds that hatchlings and juveniles of all tested pterosaurs had adult proportions. We know from phylogenetic analysis that a juvenile Rhamphorhynchus was recovered in phylogenetic analysis because it scored identical to an adult but was less than half as tall.
The specimen used to be in a private collection
of the quarry owners. It was discovered in 1965 and recently sold to the Tyrrell. It is preserved in ventral view with light impressions of wing membranes and a trapezoidal tail vane.
Hone et al. report, “Some sutures in the skull can be tentatively identified but these are mostly not clear, either because they are being obliterated as a result of cranial fusion during ontogeny, or owing to crushing of elements.” Here (Fig. 3). DGS colorizes the skull bones. I did not notice any obliteration in the sutures.
Figure 3. Rhamphorhynchus Tyrrell specimen after DGS colorizing of the bones.
Hone et al. considered the tooth count (twelve uppers, ten lowers) “higher than normal” for Rhamphorhynchus (ten uppers, seven lowers), but the extras appear to be incipient teeth or tooth tips from the right side of the skull.
Hone et al. identify four sacrals (Fig. 5), not counting the anterior vertebrae that lie between the ilia and sends out processes to the anterior ilia.
Hone et al. report, “The divisions between the vertebrae are difficult to distinguish along the majority of the length of the tail and parts are covered by the left pes, so a vertebral count is not possible.” I had less of an issue while applying DGS (Fig. 4). But then I had only a jpeg, not the real thing. The photo looks good. Is this a case where DGS trumps first hand observation? See figure 6 for comparison.
Figure 4. Rhamphorhynchus, Tyrrell specimen, caudals. They are distinct from one another contra Hone et al. 2015. Click to enlarge.
Hone et al. report, “Numerous dorsal ribs and gastralia are preserved on the specimen but a count is not possible given that many elements overlap one another.” This is exactly what DGS does best (Fig. 5) because the eye get overwhelmed by the chaos and colors segregate and ultimately simplify the issue.
Figure 5. Torso of Rhamphorhynchus from Hone et al. 2015. Above as originally interpreted. Below using DGS. What Hone et al. identify as a mc (metacarpal) is the radius + ulna. Scale bar = 2 cm. One rib is actually a prepubis. It is much more robust then even the anterior ribs. A fifth acral rib is identified here. The coracoids are in light blue. The light gray areas maybe an egg. A smaller second possible egg is also in gray. The sternal complex (not just the sternum) appears to be broken into several parts. Fibula parts are identified along with a second ischium.
Hone et al. refer to the sternal complex as the sternum. That’s inexact. They know it’s not just a sternum, but also includes the clavicles and interclavicle. Nesbitt (2011) assumed these latter elements were missing from pterosaurs in his analysis, so such deletions have real world consequences in cladograms.
Figure 6. Rhamphorhynchus Tyrrell specimen right wing GIF movie showing vane and wing tip ungual visible in high contrast. Note the lack of differentiated caudal vertebrae. Click to enlarge.
Wings and their membranes
Hone et al. identify an ulna where an ulna + radius is present, as described in their text. In prior works these authors have supported the deep chord wing membrane false hypothesis, despite all evidence demonstrating otherwise. Here again is another narrow chord wing membrane with a direct connection to the elbow. That the knees are drawn up does not negate this observation, which is universal in pterosaurs.
FIgure 9. Rhamphorhynchus left wing GIF movie (click to enlarge) showing radius + ulna, pteroid and standard narrow chord wing membrane.
Hone et al. note that both wings terminate in a squared off tip. They were not present when this specimen was prepared 50 years ago. I agree that no wing tip ungual is readily apparent here, as opposed to the many seen on several specimens previously. If you bump up the contrast on the matrix, several ungual candidates appear (Fig. 10). The “squared-off tip” described by Hone et al. looks like any other articular surface, as in the other interphalangeal joints on the wing. This should have been noted.
Figure 10. Right wing tip of Tyrrell specimen of Rhamphorhynchus showing blunt tip and, with higher contrast, several ungual candidate impressions.
Figure 11. Pelvic elements of Rhamphorhynchus, Tyrrell specimen, replaced to their in vivo positions in lateral view along with the two possible egg candidates for comparison to the pelvic opening. Seems like a good fit. The prepubis, originally identified as a rib, has no counterparts among the ribs. It is more robust and straighter.
Hone et al. report, “The pelvis is partially disarticulated and some elements appear to have been lost.” The ilia are both easy to see. Hone et al. report, “The proximal part of the right pubis is articulated with the right ilium, but only the articular end is visible and the rest appears to be hidden below other elements.” I did not see that. I did see both pubes scattered in the mix (Fig. 5). They are not readily apparent. Hone et al. report, “Only one ischium (?right) can be identified.” I found both (Fig. 5) parallel to each other. Hone et al. report, “Both prepubes are preserved but are in poor condition and covered by other elements. They are in close association but are not articulated with one another and lie posterior and ventral to the sacrum.” The authors did not identify the prepubes in their tracings. In ventral view the prepubes should not be covered by other elements (which elements?). I found one prepubis, misidentified as a rib by Hone et al. and the other one where they said it was. I don’t think they realize how large the prepubes are in this species of Rhamphorhynchus, which is a ‘chubbier’ pterosaur than most others owing to its long ribs, gastralia and deep prepubes. No other ribs are robust like the prepubis. And all of the anterior ribs, those likely to be more robust, but are not in this species, are accounted for. Plus it matches the darkling prepubis (Fig. 12).
Figure 12. The darkling specimen of Rhamphorhynchus, very similar to the Tyrrell specimen, showing the depth of the gastralia and prepubis.
traits alone nested the Tyrrell specimen within its clade as this is the only clade with penultimate pedal phalanges longer than the others (Fig. 13). Click here to see others.
Figure 13. Pes of the Tyrrell specimen of Rhamphorhynchus.
The wing membrane
Hone et al. report, “Each wing has a more narrow chord along most of its length than seen in some specimens of Rhamphorhynchus (e.g., BSPG 1938 I 503a, the ‘DarkWing’ specimen—Frey et al., 2003) suggesting some postmortem shrinkage of the membranes (Elgin, Hone & Frey, 2011).”
There is no shrinkage!
Hone et all are refusing to face the facts. They are making up scenarios to avoid the narrow-wing morphology (Peters 2002). This pterosaur, like all others, has a narrow chord wing membrane. Hone et al acknowledge that. And so does the dark-wing specimen, as documented earlier and shown below (Fig. 14). When the wing is outstretched, as if in flight, the membrane goes with the wing finger and it is stretched between the elbow and wing tip. Any other attachment points needlessly complicate matters. Any other scenarios are excuses and just-so stories.
Figure 15. The darkwing specimen of Rhamphorhynchus. Top: in situ. Middle: Soft tissues highlighted. Bottom: Neck and forelimb restored with wings outstretched. This is another narrow chord wing membrane when the parts are restored to their in flight position. The arrows show how much the wing would have to stretch to attach to the ankle. But there’s no muscle and bone to stretch it. Remember, in flight the tibia stick almost straight out laterally,
Biut wait… there’s more!
Hone et al. report, “Proximal to the elbow, the right tenopatagium (Fig. 6) is rather less clearly preserved than the left actinopatagium (Fig. 5), but does appear to meet the left ankle as is considered common, or even ubiquitous, for pterosaur wing membranes (Elgin,Hone & Frey, 2011).” Yeah, right… This is really reaching. This is why these guys keep rejecting my papers and why I don’t attend pterosaur symposia. They are adamant about rejecting anything I have published on. Evidently, I have (figuratively) poisoned the well. And that’s a sorry state of affairs. They will never say, “well, I guess Peters 2002 was right about the narrow chord wing membrane. It’s right here in front of us.”
You should know
Hone et al. report, “Furthermore, at least some parts of the wings have been covered with some form of transparent preservative and brush marks (e.g., swirls) are clearly visible in places on the matrix.”
Uropatagia are preserved
But due to the extreme bending of the knees, their shape cannot be determined. Hone et al. provided an extreme closeup of fibrils in a uropatagium (their figure 7, but note the singular state here as they falsely believe, based on the Sordes error, that one membrane extended from leg to leg). They reported the element on the right is the right tibia, but the right tibia is devoid of tissue, as far as I can tell. I was unable to match the extreme closeup to any other wider view shots. There does appear to be soft tissue between the left femur and tibia (remember the specimen is on its back so left is right and right is left). Their figure 8 has a wider view and represents the left tibia. Still the fibrils are close to the tibia and they provide no evidence that these are not separate uropatagia, as in all other pterosaurs.
Hone et al report gut contents of an indeterminate vertebrate. “most of these are distorted and difficult to identify though their overall shape appears to be that of squat cylinders. Their exact identity cannot be determined as they are incomplete and partially covered by other elements, and much of the chest cavity has calcite crystal buildup. –– These bones may represent fish or tetrapod elements, but are not part of the pterosaur as they match none of the dissociated or missing material (ribs, gastralia, sternal ribs, pteroids, pelvic elements) but instead are a sub rectangular series and associated subcircular elements that collectively may be vertebrae (Fig. 3).” Rhamphorhynchus is typically considered a fish eater as fish have been found within certain specimens. ‘Hooklets’ [= simple spikes and hook-like shapes] are found by the thousands in the coprolites. Hone et al. report, “If the diagnosis is correct, this is the first recorded coprolite for any pterosaur.”
Odd that the torso should be so upset, but the soft coprolites untouched.
Hone et al. did not consider the possibility
of an internal immature egg. The item has an oval outline (Fig. 11). And there may be a second smaller, even more immature egg in the mix (Fig. 11). Hard to tell in all that chaos.
Hone et al. are correct in stating the Tyrrell specimen is adult or nearly so. But sutures are not a reliable indicator of ontogeny. Several clades fuse early and others never fuse, patterns common to lepidosaurs, not archosaurs.
Perhaps these can be corrected since they are online:
- “several specimens seen to have consumed fish”
- The uropatagium has become displaced relative to the bones even in some exceptionally preserved specimens (e.g., Sordes PIN 2585-33). The holotype is PIN 2585-3). I find no record for #33 on the Internet.
Hone D, Henderson DM, Therrien F and Habib MB 2015. A specimen of Rhamphorhynchus with soft tissue preservation, stomach contents and a putative coprolite. PeerJ 3:e1191; DOI 10.7717/peerj.1191