Re-description and Reassignment of the Damselfish Abudefduf luridus (Cuvier, 1830) Using Both Traditional and Geometric Morphometric Approaches
Here we present a re-description of Abudefduf luridus and reassign it to the genus Similiparma. We supplement traditional diagnoses and descriptions of this species with quantitative anatomical data collected from a family-wide geometric morphometric analysis of head morphology (44 species representing all 30 damselfish genera) and data from cranial micro-CT scans of fishes in the genus Similiparma. The use of geometric morphometric analyses (and other methods of shape analysis) permits detailed comparisons between the morphology of specific taxa and the anatomical diversity that has arisen in an entire lineage. This provides a particularly useful supplement to traditional description methods and we recommend the use of such techniques by systematists. Similiparma and its close relatives constitute a branch of the damselfish phylogenetic tree that predominantly inhabits rocky reefs in the Atlantic and Eastern Pacific, as opposed to the more commonly studied damselfishes that constitute a large portion of the ichthyofauna on all coral-reef communities.
Principal component score plot generated from a geometric morphometric analysis of damselfish cranial anatomy (all damselfish genera and 44 select species were sampled). Principal component 1 (the X axis) and principal component 2 (Y axis) account for 42.14% and 16.98% of the total head shape data in the dataset, respectively. Species of Abudefduf examined □: Abudefduf bengalensis, Abudefduf saxatilis, Abudefduf septemfasciatus, Abudefduf sexfasciatus, Abudefduf sordidus, Abudefduf taurus, Abudefduf whitleyi. Similiparma and closest relatives ○: Hypsypops rubicundus, Microspathodon dorsalis, Nexilosus latifrons, Similiparma hermani, Similiparma lurida. Key to other pomacentrids examined •: Acanthochromis polyacanthus (Apoly), Amblyglyphidodon curacao (Acur), Amblyglyphidodon leucogaster (Aleu), Amblypomacentrus breviceps (Abre), Amphiprion akindynos (Aaki), Azurina hirundo (Az), Cheiloprion labiatus (Clab), Chromis amboinensis (Camb), Chromis multilineata (Cmul), Chromis punctipinnis (Cpun), Chromis weberi (Cweb), Chrysiptera brownriggii (Cbro), Chrysiptera cyanea (Ccya), Chrysiptera oxycephala (Coxy), Dascyllus melanurus (Da mel), Dischistodus melanotus (Di mel), Hemiglyphidodon plagiometopon (Hpla), Lepidozygus tapeinosoma (Ltap), Mecaenichthys immaculatus (Mimm), Neoglyphidodon melas (Nmel), Neoglyphidodon nigroris (Nnig), Neoglyphidodon oxyodon (Noxy), Neoglyphidodon thoracotaeniatus (Ntho), Neopomacentrus azysron (Nazy), Parma microlepis (Pmic), Plectroglyphidodon lacrymatus (Plac), Pomacentrus alexanderae (Pale), Pomachromis richardsoni (Pric), Premnas biaculeatus (Pbia), Pristotis obtusirostris (Pobt), Stegastes flavilatus (Sfla), Teixeirichthys jordani (Tjor). See Figure 2 for a morphological description of the shape variation described by PC1 and PC2.
Pictorial descriptions of the morphometric axes depicted in Figure 1. (A) Microspathodon dorsalis. (B) Nexilosus latifrons. (C) Similiparma lurida showing the landmarks analyzed in the shape analysis. (D) Azurina hirundo. (E) Neoglyphidodon nigroris. The head shape differences between the specimens in plates A and D describe the morphological variation associated with the X axis (PC 1) in Figure 1. Specimens with low PC 1 scores (those toward the left of the X axis) have heads that are compact in terms of anterior-posterior extension. They also have larger A2 divisions of the adductor mandibulae (the lower portion of the biting muscle complex; the A2 inserts on the primordial process of the articular in the lower jaw), shorter jaw bones, smaller eyes located higher on the head, taller supraoccipital crests, more subterminal mouths and shorter ascending processes on the premaxillae that prohibit extensive jaw protrusion. The head shape differences between the specimens in plates B and E describe the morphological variation associated with the Y axis (PC 2) in Figure 1. Specimens with low PC 2 scores (those toward the bottom of the Y axis) have smaller A1 divisions of the adductor mandibulae (the upper portion of the biting muscle complex; the A1 inserts on the maxilla in the upper jaw). See Figure 4 for further damselfish head shape details.
Range of Similiparma lurida. Dotted line denotes the Macaronesian region. The range of P. lurida is limited to Macaronesia and the adjacent African coastal waters. Image derived from Google Earth (http://www.google.com/earth/index.html).
Comparative skeletal anatomy of Similiparma lurida (A and C) and S. hermani (B and D). A and B are images of skeletonized specimens.C and D are images derived from micro-computed tomography scans.
Comparisons of craniofacial profile curvature in Similiparma hermani (A) and S. lurida (B) when scaled to the same head size. The circles fitted to the peripheries of the eyes are exactly the same size in A and B. C depicts the size of the circles needed to describe the craniofacial profile in both species when scaled to the same head size.
Similiparma hermani (FMNH 121168) collected and photographed by W. J. Cooper.
Lower pharyngeal jaw (A) and left portion of upper pharyngeal jaw (B) from Similiparma lurida.
Contributor Notes
Associate Editor: W. L. Smith.