Ostromia: The Haarlem specimen of Archaeopteryx

Updated January 17, 2018 with a new tracing and nesting of Ostromia as a sister to Eosinopteryx in the proximal outgroup clade to the birds. 

Updated June 23, 2109 with revised closeup images of the pelvis, ‘clavicle’ and pes.

A recent paper
by Foth and Rauhut 2017 reexamined the incomplete Haarlem specimen on plate and counter plate (TM 6928, 6929, Figs. 1–3) originally attributed to a pterosaur (Pterodactylus crassipes, von Meyer 1857) and later to Archaeopteryx crassipes (Ostrom 1970). The co-authors renamed the specimen Ostromia crassipes and nested it with Anchiornis (Fig. 2), a larger troodontid with a short coracoid outside of the bird clade in the large reptile tree (LRT).

Figure 1. The Haarlem specimen of Archaeopteryx now named Ostromia crassipes.

Figure 1. The Haarlem specimen of Archaeopteryx now named Ostromia crassipes.

Foth and Rauhut 2017
considered Anchiornis“the possibly oldest and most basal clade of avialan, here named Anchiornithidae.” And they considered Ostromia the first and only anchiornithid outside of the Tiaojushan Formation of China.

Figure 1. Anchiornis, the pre-bird troodontid, to scale with Ostromia, the Solnhofen bird, the Haarlem specimen.

Figure 1. Anchiornis, the pre-bird troodontid, to scale with Ostromia, the Solnhofen pre-bird, the Haarlem specimen.

The authors employed a previously published phylogenetic analysis
from Foth et al. 2014. which looked at the privately owned 11th specimen of Archaeopteryx. Unfortunately their cladogram lumped all Archaeopteryx specimens (Fig. 3) together. So we’re dealing with a possible taxonomic chimaera and a certain taxon exclusion.

Figure 3. Several Solnhofen birds, including Archaeopteryx, compared to Ostromia to scale.

Figure 3. Several Solnhofen birds, including Archaeopteryx, compared to Ostromia to scale.

The variety shown by the Solnhofen birds
(Fig. 3) should invite phylogenetic analysis (Fig. 4). But Foth et al. (2014, 2017) did not respond to the invitation. If they had done so, perhaps they would have replicated the results of the LRT in nesting Ostromia with other coeval Archaeopteryx specimens. Their Ostromia nests here with Eosinopteryx, not with Anchiornis.

In size, strata and morphology
Ostromia nests rather closely to the other Solnhofen birds in the LRT, but in the proximal outgroup, along with Eosinopteryx and Xiaotingia.

I encourage bird workers
to not lump the Solnhofen birds together as a single taxonomic unit, but to split them into individual specimens. There’s a treasure to be found there. Each one deserves to be its own species, if not its own genus.


Revised images in detail

Closeup figure of femora and pubis of Ostromia.

Figure x. Closeup figure of femora and pubis of Ostromia traced on data from both plates. It is still tricky to see the elements. Blue lines could be bones or soft tissue in this fossil.

Figure y. Closeup of possible displace clavicle with alternate curved rib and busted clavicle interpretation.

Figure y. Closeup of possible displace clavicle with alternate curved rib and busted clavicle interpretation.

Figure z. Pedes of Ostromia in greater precision and closeup. It is apparent that digit 2 on both pedes had a robust ungual and phalanges.

Figure z. Pedes of Ostromia in greater precision and closeup. It is apparent that digit 2 on both pedes had a robust ungual and phalanges even accounting for displaced keratin sheaths.


References
Foth C and Rauhut OWM 2017. Re-evaluation of the Haarlem Archaeopteryx and the radiation of maniraptoran theropod dinosaurs. BMC Evolutionary Biology 17:236
Foth C, Tischlinger H, Rauhut OWM 2014. New specimen of Archaeopteryx provides insights into the evolution of pennaceous feathers. Nature 511:79–82.
Ostrom JH 1970. Archaeopteryx: notice of a “new” specimen. Science. 1970;170:537_538.
Von Meyer H 1861. Archaeopteryx lithographica und Pterodactylus. N Jb Min Geognosie Geol Petrefaktenkd. 1861:678–679.

TM = Teylers Museum in Haarlem, the Netherlands

4 thoughts on “Ostromia: The Haarlem specimen of Archaeopteryx

  1. Having seen the actual fossil up close many times, there seem to be some issues with that reconstruction of Ostromia.

    What looks to be a furcula on the drawing simply isn’t there on the actual fossil. Running along the lower curve there is only a rib fragment. Same issue with the sternum? big green shape on the abdomen. That area is where all the gastralia are located and the shape around it is just rock. And gastralia have been drawn in a place where there are none (between the abdomen area and hand).

    The pubis is also not nearly as curved as shown here though much of it is only an impression of bone like most of the specimen.
    The one claw on the foot is also much too big. On the actual fossil the keratin sheaths make some of the claws look larger at a glance because some of these sheaths have slipped out of their original position.

    • Some closeup GIF images are provided, Olof. Your comments will be appreciated. I regret not taking the same care to provide this much precision earlier. I must have had something else demanding my attention that day. The technique of combining plates and tracing with colors can only be done on a computer monitor, not a microscope with firsthand observations.

      • Thank you for your reply.
        I’ve actually done a reconstruction of this animal myself some ten years ago. I used a similar technique, though I used my own closeup photos. Then I compiled those in Illustrator to make a vector drawing of it.

        Even behind glass, the specimen is actually fairly easy to photograph up close in fairly decent light. Looking back I made a few mistakes myself. And I kinda need to revisit my reconstruction as well. Though much of it still holds up. The main mistake I made was precisely with the slippage of the keratin sheaths as I didn’t know those were the actual keratin part at the time. So I had added one claw too many that turns out to be just a sheath for one of the other claws.
        You can view my reconstruction here. Though there are some definite mistakes, most of the bones should still be pretty accurate.
        https://www.deviantart.com/olofmoleman/art/Haarlem-Archaeopteryx-88632473

        And as it happens I’ve just finished a photogrammetry scan of the specimen. That’s how I stumbled on your reconstruction and noticed some clear differences.
        Again based on my own photos, much more high resolution this time I was able to make a fairly accurate scan. Feel free to use it as reference.

        Though the photogrammetry process isn’t perfect, so there might be some slight distorting, especially on the sides of the matrix. There is little preserved near the sides however, so that isn’t that big a loss. There is also some shifting of the photos, so some bones may appear to be broken. So I wouldn’t use it as direct reference to trace from. But the texture projected onto the model is made from high res closeup photos I took, so it could potentially be useful for use in how to interpret the bones.

        And yeah I can understand it can be pretty hard to interpret bones from photos of limited resolution. So hopefully these resources might be of use to you.

        Cheers,
        Olof Moleman

  2. Thank you for your careful and considerate comments, Olof. Unfortunately I can only interpret the data I acquire, sometimes it is low resolution or old line drawings. Better images are always appreciated and reviewed if you have any to share. On the same point, some of what I trace can be misinterpreted by the reader. What looks like a giant sternum shape, for instance is much larger than in sister taxa. It is best to think of it only as a first-draft shape still needing a label or refinement. The same goes for the parallel curved lines you identify as gastralia. They are smaller than in sister taxa and lie atop some preserved feathers, so that is probably their origin. If the clavicle bone is not present, could that semi-clavicle shape be an impression from a counter plate, or parallel displaced ribs? The toe keratin sheath can be displaced, as you suggest. In either case, the LRT does not score for deeper digit 2 unguals, so that data is irrelevant to the matrix. Bottom line: I have corrected tens of thousands of errors when better data comes along. It’s a never-ending task given the size of the present taxon list. Thank you for your input.

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