Growth, age and size of the Jurassic pachycormid Leedsichthys problematicus (Osteichthyes: Actinopterygii)

Liston, J., Newbrey, M., Challands, T. and Adams, C. (2013) Growth, age and size of the Jurassic pachycormid Leedsichthys problematicus (Osteichthyes: Actinopterygii). In: Arratia, G., Schultze, H. and Wilson, M. (eds.) Mesozoic Fishes 5 – Global Diversity and Evolution. Verlag Dr. Friedrich Pfeil: München, Germany, pp. 145-175. ISBN 9783899371598

Abstract

The Jurassic pachycormid osteichthyan Leedsichthys problematicus is renowned for having been able to achieve prodigious size for a bony fish. Building on work of MARTILL (1986a), a thorough examination of all known material was conducted in order to constrain estimates of the size of this animal and examine its rate of growth. Important specimens of Leedsichthys are described for the first time. The histology of Leedsichthys is reviewed, and the presence of growth annuli is used to establish ages for five specimens. Age and growth data were obtained from gill rakers (n = 4) and lepidotrichia (n = 2). Lepidotrichia show upward curvilinear growth profiles and ages ranging from 21 to 40 annuli, which are assumed to represent years. Both growth profiles start at a small size (0.26 and 0.33 mm radial distance), which is assumed to represent age 1. However, annuli can be lost near the margins of the elements. Gill rakers exhibit a sigmoidal growth profile. Age of gill rakers was estimated by adjusting the alignment of the inflection points of the growth profiles thereby giving adjusted ages. Gill rakers ranged in age from 19–38 annuli, but all show evidence of reabsorption of annuli near the focal points and at the margins of most elements. Sizes for the five individuals range from 8.0-16.5 m for ages of 19-40 years. Growth rate (0.01-0.05 K) was relatively slow as expected for a large, long-lived fish. At age 1, individuals were 1.6 m in length. Estimates for the length of L. problematicus compare well with published lengths of other large suspension feeders such as those for basking and whale sharks.

• Item Type: Book Sections
• Status: Published
• Glasgow Author(s) Enlighten ID: Challands, Dr Tom and Adams, Professor Colin and Liston, Dr Jeff
• Authors: Liston, J., Newbrey, M., Challands, T., and Adams, C.
• Subjects: Q Science > QH Natural history; Q Science > QH Natural history > QH301 Biology; Q Science > QL Zoology
• College/School: College of Medical Veterinary and Life Sciences > School of Life Sciences; University Services > Library and Collection Services > Museum and Art Gallery; College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Publisher: Verlag Dr. Friedrich Pfeil
• ISBN: 9783899371598
• Copyright Holders: Copyright © 2013 Verlag Dr. Friedrich Pfeil
• Publisher Policy: Reproduced with the permission of the publisher