皮骨角
皮骨角[1]（英語：Ossicones）是指长颈鹿、雄性㺢㹢狓等动物头上类似于角、鹿角的结构。此外，现已灭绝的西瓦鹿和梯角鹿科动物（如Climacoceras）头部也生有这种结构。[2]部分学者曾认为这些灭绝种头部的皮骨角并非真正意义上的皮骨角；不过后续的研究表明，这些动物的皮骨角和长颈鹿科的动物很接近。皮骨角位于背骨、额骨上，随着年龄的增加会逐渐长到头骨上。[3]
皮骨角和羚羊、家牛的角类似，区别在于皮骨角由软骨组织骨化而成，而非由活骨直接形成，[4]而且皮骨角上由皮毛覆盖，而非角蛋白。
皮骨角一出生起就存在，但刚生下来时皮骨角贴着头部而不是长在头骨上，以防降生时受伤。[5]雄性动物和雌性动物的皮骨角结构、用途都有不同。雄性的皮骨角更厚，因雄性长颈鹿喜欢脖击而导致皮骨角顶部的骨骼裸露出来。这些皮骨角还会增加长颈鹿头部的重量，使得其脖击时的攻击威力更大，有时甚至能致命。皮骨角的出现也导致了一些其他的进化特征，如动物的外皮更重，真皮层也出现了特化的防御。[6]
参考资料
- ^ 邱占祥; 阎德发; 贾航. 山东山旺Palaeomer yx化石的初步研究 (PDF). 古脊椎动物学报. 1985-07, 23 (3): 173–195 [2019-12-22].
- ^ Hadar Picture Gallery. An ossicone of the extinct, giant, short-necked giraffe. University of Washington.
- ^ Solounias, N. Prevalence of Ossicones in Giraffidae (Artiodactyla, Mammalia). Journal of Mammalogy. 1988, 69 (4): 845–8. JSTOR 1381645. doi:10.2307/1381645.
- ^ The Nashville Zoo at Grassmere – Animals :: Masai Giraffe. Nashville Zoo at Grassmere. 2008-06-30. （原始内容存档于2008-06-30）.
- ^ FAQs - GiraffeConservation.org. GiraffeConservation.org. [2018-04-26] （美国英语）.
- ^ Geist, Valerius. The Evolution of Horn-Like Organs. Behaviour. 1966, 27 (1): 175–214. doi:10.1163/156853966x00155.
拓展阅读
- Hou, Sukuan; Danowitz, Melinda; Sammis, John; Solounias, Nikos. Dead ossicones, and other characters describing Palaeotraginae (Giraffidae; Mammalia) based on new material from Gansu, Central China. Zitteliana. 2014, 32: 91–8.
- Solounias, N; Moelleken, S. M. C. Evidence for the Presence of Ossicones in Giraffokeryx punjabiensis (Giraffidae, Mammalia). Journal of Mammalogy. 1991, 72 (1): 215–7. JSTOR 1382004. doi:10.2307/1382004.
- Churcher, Charles S. Cranial Appendages of Giraffoidea. Horns, Pronghorns, and Antlers. 1990: 180–94. ISBN 978-1-4613-8968-2. doi:10.1007/978-1-4613-8966-8_5.
- Davis, E. B; Brakora, K. A; Lee, A. H. Evolution of ruminant headgear: A review. Proceedings of the Royal Society B: Biological Sciences. 2011, 278 (1720): 2857–65. JSTOR 41315010. PMC 3151718
. PMID 21733893. doi:10.1098/rspb.2011.0938. 简明摘要 – ScienceDaily (July 10, 2010). - Danowitz, Melinda; Barry, John C; Solounias, Nikos. The earliest ossicone and post-cranial record of Giraffa. PLOS ONE. 2017, 12 (9): e0185139. PMC 5605118 . PMID 28926638. doi:10.1371/journal.pone.0185139.
- Ríos, María; Sánchez, Israel M; Morales, Jorge. A new giraffid (Mammalia, Ruminantia, Pecora) from the late Miocene of Spain, and the evolution of the sivathere-samothere lineage. PLOS ONE. 2017, 12 (11): e0185378. PMC 5665556 . PMID 29091914. doi:10.1371/journal.pone.0185378. 简明摘要 – Science (November 2, 2017).