生物谷报道：瑞士，英国及拉脱维亚科学家近日发现了最原始的四足动物孔螈的头骨，这一发现将有助于科学家更好地了解鱼到陆地爬行动物的进化过程。
据悉，这具有3亿5千年历史的头骨化石是在拉脱维亚发现的，科学家将这一报告刊登在了6月26日发行的《自然》（Nature）杂志上。
科学家推测说，这一长相凶猛的动物可能生活在浅水含盐较高水域，长3到4英尺，捕食鱼类。（生物谷www.bioon.com）
生物谷推荐原始出处：
Nature，453, 1199-1204，Per E. Ahlberg，Ivars Zupi
Ventastega curonica and the origin of tetrapod morphology
Per E. Ahlberg1, Jennifer A. Clack2, Ervns Lukevis3, Henning Blom1 & Ivars Zupi4
Subdepartment of Evolutionary Organismal Biology, Department of Physiology and Developmental Biology, Uppsala University, Norbyvägen 18A, 752 36 Uppsala, Sweden
University Museum of Zoology, Cambridge, Downing Street, Cambridge CB2 3EJ, UK
Department of Geology, University of Latvia, Rainis Blvd 19, Riga LV-1586, Latvia
Natural History Museum of Latvia, K. Barona Str. 4, Riga LV-1712, Latvia
Correspondence to: Per E. Ahlberg1 Correspondence and requests for materials should be addressed to P.E.A. (Email: per.ahlberg@ebc.uu.se).
Abstract
The gap in our understanding of the evolutionary transition from fish to tetrapod is beginning to close thanks to the discovery of new intermediate forms such as Tiktaalik roseae. Here we narrow it further by presenting the skull, exceptionally preserved braincase, shoulder girdle and partial pelvis of Ventastega curonica from the Late Devonian of Latvia, a transitional intermediate form between the 'elpistostegids' Panderichthys and Tiktaalik and the Devonian tetrapods (limbed vertebrates) Acanthostega and Ichthyostega. Ventastega is the most primitive Devonian tetrapod represented by extensive remains, and casts light on a part of the phylogeny otherwise only represented by fragmentary taxa: it illuminates the origin of principal tetrapod structures and the extent of morphological diversity among the transitional forms.
