Phylogeny of Living Parasitic Lampreys (Petromyzontiformes) Based on Morphological Data

Ancient Phylogenetic Separation between Pacific and Atlantic Cephalochordates as Revealed by Mitochondrial Genome Analysis

“…All the three subfamilies (Mordaciinae, Geotriinae, and Petromyzoninae) in the lamprey lineage are thought to have diverged from one another in a considerably short period of time (Conlon et al, 2001;Gill et al, 2003), as indicated by ambiguous phylogenetic relationships between these three taxa in recent molecular studies (Baldwin et al, 1988;Silver et al, 2004;Takahashi et al, 2006). Our synonymous substitution clock indicates that the Geotriinae-Petromyzoninae split occurred in the Permian-Triassic Periods (280-220 Mya; Fig.…”

“…The other subfamily, Eptatretinae, consists of three genera, Eptatretus, Paramyxine, and Rubicundus. In contrast, the order Petromyzoniformes is composed of three subfamilies, Mordaciinae, Geotriinae, and Petromyzoninae, in accordance with morphology such as dentition (Hubbs and Potter, 1971;Gill et al, 2003). The subfamilies Mordaciinae and Geotriinae are endemic to the southern hemisphere, and each comprises a single genus, Mordacia and Geotria, respectively (Potter and Strahan, 1968).…”

Early evolution of multifocal optics for well-focused colour vision in vertebrates

“…1). The 38 known species of lampreys have an anti-tropical distribution with 34 species occurring in the northern hemisphere and four species in the southern hemisphere (Gill et al, 2003). We studied two species from the northern hemisphere: Lampetra fluviatilis and Petromyzon marinus, and two species from the southern hemisphere: Mordacia praecox and Geotria australis.…”

Early evolution of vertebrate photoreception: lessons from lampreys and lungfishes

“…Although all 34 species of northern hemisphere lampreys (Renaud 1997) are placed in a single family (the Petromyzontidae), the 4 species of southern hemisphere lampreys are separated into either the Geotriidae or Mordaciidae. It has been proposed that these latter two families were derived independently from stocks similar to those of contemporary representatives of the holarctic genus Ichthyomyzon (Hubbs & Potter 1971;Potter & Hilliard 1987;Gill et al 2003). The Geotriidae is represented solely by Geotria australis Gray, 1851 an anadromous species, which is found in rivers in New Zealand, southern Australia, Tasmania, Chile and Argentina (Potter & Strahan 1968), while the Mordaciidae contains 2 anadromous species (Mordacia mordax Richardson, 1846 and Mordacia lapicida Gray 1851), restricted to rivers in eastern Australia and Chile, respectively (Potter & Strahan 1968).…”