The next osteoderm is even triangular however, large versus very first osteoderm

The next osteoderm is even triangular however, large versus very first osteoderm

5.8.step 1 Anterior cervical paramedian osteoderms

The initial about three paramedian rows of the right-side is maintained in the PEFO 34561, and several rows try managed during the PEFO 42442/UWBM 116869 (Figure 12h). The initial osteoderm is roughly triangular inside the dorsolateral examine that have upright medial and you will rear entation is weakly incised, and there’s zero anterior club. Rather, to your anterior ventral facial skin discover a good scalloped, rugose surface to have articulation with the posterior margin of the head. This osteoderm is much like the first in its morphology but that it lacks the latest ventral articular skin and alternatively keeps a weakened anterior pub across the narrow prior margin. The third osteoderm is rectangular (mediolateral width:anteroposterior size proportion out of 2.0), which have a great dorsal ornamentation off small pits. So it osteoderm was arched close the horizontal line, and there is a pronounced prior pub which have an effective triangular prior projection during the area out-of arching. This new amino apk ventral surface of the plate is actually simple. During the dorsal have a look at, brand new medial margin was upright, while the fresh lateral margin try lightly game and you can does not have a keen articular surface having a lateral osteoderm.

5.8.2 Middle and you may rear cervical paramedian osteoderms

Cervical paramedian osteoderms is actually wide than much time (mediolateral thickness:anteroposterior duration proportion regarding 2.5 excluding this new anterior club) and appearance so you’re able to expand quite for the per further posterior row (Contour 12h). New dorsal pitting are reduced and you can weakly incised. The latest prior pub makes up you to definitely-fifth of total period of the newest osteoderm. This new prior margin of your osteoderm try upright and you may lacks anteromedial and you will prior forecasts. This new osteoderm try quite arched near the horizontal boundary, two-thirds the distance on the medial border. There’s absolutely no dorsal eminence of point where osteoderm is actually curved. When you look at the dorsal view the medial margin of the osteoderm try straight, while the fresh new horizontal border try weakly rounded. The latest lateral margins taper and have now no signs and symptoms of an articular facial skin to own a lateral osteoderm. Hence, discover at this time zero evidence getting cervical lateral osteoderms inside R. callenderi.

5.8.step 3 Dorsal trunk paramedian osteoderms

Dorsal paramedian osteoderms are termed particularly because they shelter the trunk spine show (Much time & Ballew, 1985 ). Such osteoderms (Rates 12a, b, h) features mediolateral width:anteroposterior length ratios of around dos.2 excluding the latest prior pub. The newest dorsal pitting throughout these plates is huge and a lot more incised upcoming with the cervical paramedians. In the dorsal consider, the medial margin is actually straight, and horizontal border a bit rounded. As with the new cervicals, these types of osteoderms is transversely curved close to the lateral margin; yet not, a number of of them osteoderms there was good dorsal eminence when you look at the the type of a keen anteroposterior ridge one does not have pitting and connections the brand new posterior margin of osteoderm. It ridge is much more noticable in the a lot more posteriorly dependent osteoderms, nevertheless the particular status of the transform is not clear from inside the the present material. The anterior pub is better-developed but constitutes lower than you to-5th of full duration of the new osteoderm, compared to this new cervical osteoderms. Furthermore, there’s two line of process with the prior bar, a good triangular anterior processes prior for the dorsal eminence and you can good triangular anteromedial projection. The fresh anterior margin of your own osteoderm ranging from these two projections was concave inside the dorsal see. Similar projections in addition to concave edian plates out of non-desmatosuchin aetosaurs (age.g., Scutarx deltatylus, PEFO 34045). Brand new ventral epidermis of your osteoderm try easy.

5.8.cuatro Horizontal trunk osteoderms

The newest articulated sample PEFO 42442/UWBM 116869 (Shape 12h) saves a number of the lateral osteoderms inside the articulation (seven off to the right front side and you may half dozen on left), and additionally they was in fact present because of at the very least new middle-trunk area so you can sacral area. Cervical and you will caudal horizontal osteoderms commonly managed. There is just one set of horizontal osteoderms per line such as aetosaurs, differing out of An effective. geoffreyi, which in certain regions keeps type of external and internal lateral osteoderms ( ). The fresh horizontal osteoderms out of R. callenderi is significantly oblong (subrectangular otherwise oval, more than wider), with an elevated main keel and an adjacent ornamentation regarding low pits as in another osteoderms (Profile 12c). There is no solid medial articulation surface towards the corresponding paramedian; although not, the fresh new medial border try straight, while the horizontal edge is actually game. The fresh new horizontal osteoderms is some flexed in prior and you can posterior feedback, therefore the newest ability is put into collection of medial and you may horizontal flanges such as aetosaurs (Parker, 2007 ). Such flanges is off approximately equal proportions, and you can overall this new osteoderms are thin when compared to almost every other aetosauriforms, different notably regarding the lateral osteoderms from A good. geoffreyi, and you may aetosaurs that will be far wider in the dorsal glance at and you may either square or wide than just enough time rectangles (Desojo et al., 2013 ; ). Also, the fresh laterals from R. callenderi use up all your obvious dorsal eminences you to definitely setting elongate spines in lots of most other aetosauriforms (elizabeth.grams, desmatosuchin aetosaurs sensu Parker, 2016a ). Instead they appear similar to the brand new appendicular osteoderms found in aetosaurs and you can erpetosuchids (age.g., Ezcurra et al., 2017 ; Heckert & Lucas, 1999 ).

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