英国普茨茅斯大学的古生物学家Mark Witton博士通过对1.25亿年前一块飞翔爬行动物的头骨化石进行研究，发现它们可能为腐食动物——食性类似秃鹫，它们以恐龙尸体为食。这块翼龙头骨化石保存于伦敦自然历史博物馆已长达一个世纪，但直到现在Witton在研究中精确地重建了它的真实形貌后，才揭开了它的秘密。相关研究3月21日在线发表于《公共科学图书馆—综合》
Witton专门研究翼龙——一类飞翔于恐龙时代天空中的巨型带翅膀的爬行动物。在最近一次浏览博物馆的时候，他意识到这块头骨可能是头骨组合中极为重要的一块。这副闻名的阔齿帆翼龙（Istiodactylus latidens）头骨化石由两部分组成，分别是脑壳（braincase）和鄂部尖端（jaw tip），但它还存在常被忽略的第三部分——将前两者连起来的一个结构。长达100年内，阔齿帆翼龙都被认为头骨长约半米，但与身体的精确比例却仍不清楚，因为仅有部分头骨骨骼被研究过。Witton认为，新发现的第三部分对于揭示阔齿帆翼龙头部的信息极为重要，同时它也能将之前研究过的牙齿化石联系起来，它为研究阔齿帆翼龙的食谱和取食习性提供了新资料。
Witton说，帆翼龙是一类拥有极为特殊的刀面切齿的生物，因此之前就有人认为它们应该是食腐的，但相应的头骨证据却一直未出现。这块碎片表明帆翼龙头骨比预想的要短20%，它的头骨非常短、宽且长，这是研究者未曾预料到的。Witton说，只有拥有发现之眼的人，才会在老化石中发现新讯息。在伦敦自然历史博物馆珍藏着数量众多的翼龙化石宝藏。因此长期以来，与翼龙相关研究的价值在这里都被低估，或许只有遇到真正的“伯乐”，它们才会焕发出光彩。
第三块碎片显示，帆翼龙的脸颊骨非常柔软，仅有6毫米长，而整个头骨可长达450毫米，因此要发现这块碎骨需要非常细心。现代食腐鸟类中拥有相似的结构，头骨包括极硬与极软的部分，由于它们可以轻易且完全地控制已死去的猎物，因此极软部分可以在头骨中存在，因为它们不用担心它会被弄碎。同时，由于食腐鸟类需要用力拖拽尸体，因此它们的面部骨骼锚定了大量的脖颈肌肉。这块帆翼龙化石于1904年发现于怀特岛，1911年收藏于伦敦自然历史博物馆。（生物谷 bioon.com）
doi:10.1371/journal.pone.0033170
PMC:
PMID:
New Insights into the Skull of Istiodactylus latidens (Ornithocheiroidea, Pterodactyloidea)
Mark P. Witton
The skull of the Cretaceous pterosaur Istiodactylus latidens, a historically important species best known for its broad muzzle of interlocking, lancet-shaped teeth, is almost completely known from the broken remains of several individuals, but the length of its jaws remains elusive. Estimates of I. latidens jaw length have been exclusively based on the incomplete skull of NHMUK R3877 and, perhaps erroneously, reconstructed by assuming continuation of its broken skull pieces as preserved in situ. Here, an overlooked jaw fragment of NHMUK R3877 is redescribed and used to revise the skull reconstruction of I. latidens. The new reconstruction suggests a much shorter skull than previously supposed, along with a relatively tall orbital region and proportionally slender maxilla, a feature documented in the early 20th century but ignored by all skull reconstructions of this species. These features indicate that the skull of I. latidens is particularly distinctive amongst istiodactylids and suggests greater disparity between I. latidens and I. sinensis than previously appreciated. A cladistic analysis of istiodactylid pterosaurs incorporating new predicted I. latidens skull metrics suggests Istiodactylidae is constrained to five species (Liaoxipterus brachyognathus, Lonchengpterus zhoai, Nurhachius ignaciobritoi, Istiodactylus latidens and Istiodactylus sinensis) defined by their distinctive dentition, but excludes the putative istiodactylids Haopterus gracilis and Hongshanopterus lacustris. Istiodactylus latidens, I. sinensis and Li. brachyognathus form an unresolved clade of derived istiodactylids, and the similarity of comparable remains of I. sinensis and Li. brachyognathus suggest further work into their taxonomy and classification is required. The new skull model of I. latidens agrees with the scavenging habits proposed for these pterosaurs, with much of their cranial anatomy converging on that of habitually scavenging birds.
