Leonid P. Korzun

Biomechanical features of the bill and and jaw apparatus of cuckoos, turacos and the hoatzin in relation to food acquisition and processing

A morphofunctional analysis of the feeding apparatus was conducted from an evolutionary perspective on the hoatzin (Opisthocomidae), some cuckoos (Cuculidae) and some turacos (Musophagidae). These goups share a common ancestral adaptation of the bill apparatus linked to starting food processing at base of the bill. The morphofunctional analyses give results different from what is known for the Galliformes and allow the construction of the hypothesis of two trophic adaptive pathways. One followed by the Cuculidae would have led to the consumption of a large range of arthropods, including toxic species; the other, followed by the Musophagidae and Opisthocomidae, would have led to the consumption of plant parts.

Bill and hyoid apparatus of pigeons (Columbidae) and sandgrouse (Pteroclididae): A common adaptation to vegetarian feeding?

For the present study, 15 species of pigeons representing the 5 sub-families usually recognized, and 3 species of sandgrouse were examined. The skeleton and musculature of the bill and hyoid apparatus are described. Morpho-functional analyses show that from a key adaptation to the removal and deglutition (without processing) of attached plant items, pigeons would have followed two pathways, one based on the joint muscular control of the movement of the jaws (Columbinae, Treroninae, Gourinae), the other on the separate muscular control (Didunculinae, Otidiphabinae). Sandgrouse would have diverged from this latter, developing the ability to very selectively remove attached plant items as well as to peck particularly small seeds on the ground. Unexpected differences appeared between sandgrouse species which raise eco-ethological problems.

Flight of Mammals: From Terrestrial Limbs to Wings

The evolutionary acquisition of flapping flight in mammals remains one of the unresolved questions of biology. Currently, no consensus as to the morphofunctional steps through which mammals passed to gain the ability to fly by flapping wings has been reached. Flight of Mammals: From Terrestrial Limbs to Wings is the result of several years of research aimed to fill this gap in the literature. Its conclusions are based on original data obtained by dissections of musculoskeletal system of a number of species and on a biomechanical analysis of these data. In addition to a thorough discussion of anatomy and the means through which mammals acquired flapping flight, more than two-hundred detailed line drawings and images provide a picture of the mechanisms of flight in bats and colugos unavailable in any other source. The book is of interest to a wide range of biologists, not only to those who study bats. The methods and approaches used by the authors can be also applied to other groups of mammals in order to create morphofunctional scenarios of their evolution. Authors Aleksandra A. Panyutina, Leonid P. Korzun, and Alexander N. Kuznetsov are all followers of the scientific school of functional morphology developed at Department of Vertebrate Zoology, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia

Kinematics of the shoulder girdle in bats

A well known hypothetical scheme of wing move ments in a flying bat was proposed by Hill and Smith [6]. This is probably a compilation of studies of Vaughan [7, 8, etc.] and original data of these authors. According to this scheme (Fig. 1), a significant contri bution to flapping movements of wings is made by joint action of the shoulder girdle and humerus. A key element of this model is the clavicle which is presumed to be mobile in the transverse plane, with an amplitude more than 60°, from an almost vertical position of the clavicle at the beginning of the downstroke to an almost horizontal position at its end. The scapula con nected to its distal end is presumed to slide over the surface of the thorax, circumscribing respective arch. The authors of this scheme believe that, in the upper position of the wing, the scapula lies horizontally on the dorsal surface of the thorax and, in the lower posi tion, it is located lateral to the thorax in an almost ver tical (parasagittal) position. Similar ideas were devel oped in [1, etc.].

Kinematics of Chiropteran Shoulder Girdle in Flight

New data on the mechanisms of movements of the shoulder girdle and humerus of bats are described; potential mobility is compared to the movements actually used in flight. The study was performed on the basis of morphological and functional analysis of anatomical specimens of 15 species, high speed and high definition filming of two species and X‐ray survey of Rousettus aegyptiacus flight. Our observations indicate that any excursions of the shoulder girdle in bats have relatively small input in the wing amplitude. Shoulder girdle movements resemble kinematics of a crank mechanism: clavicle plays the role of crank, and scapula—the role of connecting rod. Previously described osseous “locking mechanisms” in shoulder joint of advanced bats do not affect the movements, actually used in flight. The wing beats in bats are performed predominantly by movements of humerus relative to shoulder girdle, although these movements occupy the caudal‐most sector of available shoulder mobility. Anat Rec, 296:382–394, 2013.

Forelimb Morphology of Colugos

The chapter includes four subchapters—Wing Membrane, Skeleton, Joints and Musculature, which describe, respectively, the skin membrane, osteology, syndesmology and myology of the shoulder girdle and forelimb in both extant species of the order Dermoptera. Such detailed morphological data were never published before; our current knowledge of colugo’s anatomy is based on one description of Leche with only 37 figures for all organs, summaries of most interesting features made by Chapman and Grasse and study of the wrist osteology by Stafford and Thorington. The description is supplied with 57 original illustrations—49 black-and-white drawings of myological dissections, 7 grayscale and 1 colored photos of the skeleton.

Functional Analysis of Locomotor Apparatus of Colugos

Various aspects of biology of colugos are considered, which have an influence upon their peculiar locomotion. The osteological, syndesmological and myological features described in Chap 2, are treated in accordance with the major types of locomotion of these animals (gliding, running and clinging on thick tree trunks, and suspending under branches). The corresponding mobility of the shoulder girdle elements is analyzed. Static models of the muscular forces in the forelimb and shoulder girdle are developed for the cases of gliding and clinging onto tree trunks. The chapter includes the following subchapters: Some Biological Aspects of Colugos; Gliding; Climbing up Trunks; Climbing under Branches; Mobility of Shoulder Girdle; Static Analysis of Clinging onto Trunk; Static Analysis of Gliding. It is supplied with 4 grayscale and 11 colored illustrations, which include original drawings representing kinematic and static models being considered, and the photos of alive flying lemurs which were kindly supplied by colleagues from Singapore.

Functional Analysis of Locomotor Apparatus of Bats

Various aspects of bat locomotion are considered, including terrestrial one. Wingbeat cycle and interaction of the wing with the air are discussed in detail. A new model of the shoulder girdle mobility in flight is established, which differs significantly from the common point of view. Static model of the muscular forces in the forelimb and shoulder girdle is developed for the case of mid-downstroke in forward flight. Specific features of the forelimb musculature in bats are interpreted in functional terms. The chapter includes the following subchapters: Locomotor Features of Chiropterans; Kinematics of Chiropteran Wing; Interaction of Wing with Air; Internal Biomechanics of Wing; Static Analysis of Downstroke. It is supplied with 2 grayscale and 10 colored illustrations, which include the photos of alive bats, original drawings representing kinematic and static models being considered, and additional X-ray frame sequences of the wingbeat cycle of Rousettus aegyptiacus.

Evolutionary Scenario for Establishment of Flapping Flight

This is the resultant chapter, where the most probable morphoecological evolutionary scenario of the origin of flapping flight in bats is suggested. It is based on the preceding functional analysis of the morphological peculiarities of the locomotor apparatus of gliding and flying mammals. In contrast to the common approach, the scenario is shaped here as a sequence of successive morphofunctional transformations rather than phylogenetic apomorphies. Every hypothetical transformation is approved in terms of adaptive sense and probable ecological framework. This chapter is supplied with 1 grayscale diagram representing the major morphological stages of the suggested evolutionary scenario and 4 figures with colored photos of live animals.

Comparative Morphofunctional Analysis

This is the central chapter, which summarizes the morphofunctional differences of colugos and bats as compared to terrestrial and arboreal mammals, such as tree shrews, retaining the basic Z-like parasagittal limbs. It includes the following subchapters: Morphofunctional features of shoulder girdle; morphofunctional features of free limb; flight vs. primitive locomotion of prototherians; flight vs. brachiation; flight and gliding. The chapter is supplied with two grayscale and two colored comparative morphofunctional figures.