The second osteoderm is even triangular however, wide than the very first osteoderm

The second osteoderm is even triangular however, wide than the very first osteoderm

5.8.1 Prior cervical paramedian osteoderms

The original about three paramedian rows of the right side is actually maintained into the PEFO 34561, and lots of rows was managed when you look at the PEFO 42442/UWBM 116869 (Profile 12h). The original osteoderm is approximately triangular within the dorsolateral glance at having straight medial and posterior entation are weakly incised, and there is zero anterior bar. Rather, towards anterior ventral epidermis there can be a beneficial scalloped, rugose epidermis getting articulation for the rear margin of one’s skull. This osteoderm is like the first with its morphology except so it does not have the newest ventral articular epidermis and you will alternatively has actually a great weak anterior club across the slim anterior margin. The next osteoderm is actually rectangular (mediolateral width:anteroposterior duration proportion regarding dos.0), which have a great dorsal ornamentation away from short pits. So it osteoderm was curved near the lateral boundary, as there are an obvious prior bar with a triangular anterior projection in the part away from arching. This new ventral surface of the plate are simple. In the dorsal check, the fresh new medial margin is upright, whereas the fresh lateral margin is lightly round and lacks an enthusiastic articular surface to own a lateral osteoderm.

5.8.2 Middle and you will posterior cervical paramedian osteoderms

Cervical paramedian osteoderms is greater than just long (mediolateral width:anteroposterior length proportion out-of 2.5 leaving out new prior club) and appear to widen a bit inside the for each and every subsequent posterior line (Shape 12h). The newest dorsal pitting is shorter and you can weakly incised. The brand new anterior pub is the reason you to definitely-5th of the complete length of the newest osteoderm. The fresh new prior margin of your osteoderm are upright and you can lacks anteromedial and you may anterior forecasts. Brand new osteoderm is a little arched nearby the horizontal border, two-thirds the length from the medial edge. There’s absolutely no dorsal eminence associated with area in which the osteoderm are curved. From inside the dorsal view the medial margin of the osteoderm try straight, while the newest lateral boundary try weakly rounded. This new lateral margins taper and then have zero signs and symptoms of a keen articular surface to have a lateral osteoderm. Ergo, there was at this time zero proof getting cervical horizontal osteoderms for the R. callenderi.

5.8.step 3 Dorsal trunk paramedian osteoderms

Dorsal paramedian osteoderms was called particularly because they protection the back vertebral show (Much time & Ballew, 1985 ). This type of osteoderms (Numbers 12a, b, h) enjoys mediolateral thickness:anteroposterior length percentages around 2.2 excluding the fresh anterior bar. This new dorsal pitting on these plates try larger and more incised after that on the cervical paramedians. In dorsal check, this new medial margin is upright, additionally the horizontal edge some rounded. As with the fresh cervicals, this type of osteoderms is transversely curved near the horizontal margin; although not, a number of ones osteoderms there clearly was an effective dorsal eminence within the the type of a keen anteroposterior ridge that lacks pitting and you may contacts the fresh new posterior margin of the osteoderm. This ridge is far more pronounced regarding the so much more posteriorly based osteoderms, nevertheless appropriate updates associated with the changes is not obvious from inside the the current materials. The fresh prior pub are well-create however, comprises less than that-5th of your own overall duration of the new osteoderm, in contrast to the latest cervical osteoderms. In addition, there are 2 collection of processes on the anterior club, a triangular anterior techniques prior on dorsal eminence and you may good triangular anteromedial projection. The brand new prior margin of osteoderm anywhere between both of these forecasts try concave inside dorsal examine. Equivalent projections in addition to concave edian dishes out-of non-desmatosuchin aetosaurs (elizabeth.grams., Scutarx deltatylus, PEFO 34045). The newest ventral epidermis of osteoderm is effortless.

5.8.cuatro Horizontal trunk osteoderms

This new articulated specimen PEFO 42442/UWBM 116869 (Shape 12h) conserves some of the horizontal osteoderms when you look at the articulation (eight off to the right front side and six with the remaining), and additionally they had been present through at the least the latest mid-trunk in order to sacral town. Cervical and caudal horizontal osteoderms aren’t maintained. There can be simply an individual band of lateral osteoderms for every line as with aetosaurs, different away from A good. geoffreyi, which in particular regions possess collection Bu siteyi kontrol edin of internal and external horizontal osteoderms ( ). The fresh horizontal osteoderms out of Roentgen. callenderi are significantly oblong (subrectangular otherwise oval, more than wider), with an increasing central keel and an adjacent ornamentation regarding shallow pits like in another osteoderms (Profile 12c). There isn’t any good medial articulation skin to your relevant paramedian; but not, this new medial edge is upright, while the lateral line is actually game. The brand new horizontal osteoderms are quite flexed into the anterior and you will posterior feedback, for this reason the newest feature was put into distinctive line of medial and horizontal flanges such as aetosaurs (Parker, 2007 ). These types of flanges was of roughly equal proportions, and you can full brand new osteoderms are extremely slim when compared to other aetosauriforms, varying notably regarding the horizontal osteoderms off A good. geoffreyi, and you will aetosaurs which can be much greater into the dorsal have a look at and sometimes square or wider than a lot of time rectangles (Desojo et al., 2013 ; ). Furthermore, the fresh laterals of R. callenderi use up all your pronounced dorsal eminences you to form elongate spines in many most other aetosauriforms (e.g, desmatosuchin aetosaurs sensu Parker, 2016a ). Instead they look more like this new appendicular osteoderms utilized in aetosaurs and erpetosuchids (e.grams., Ezcurra et al., 2017 ; Heckert & Lucas, 1999 ).


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