Morphological variation in the Sabota Lark Calendulauda sabota in southern Africa

• Published in: Ostrich Vol. 88; no. 1; pp. 67 - 71
• Main Authors: Marr, Sean M, Mashao, Mmatjie L, Engelbrecht, G Derek
• Format: Journal Article
• Language: English
• Published: Johannesburg Taylor & Francis 31.03.2017; Taylor & Francis Ltd
• Subjects: 75% rule for diagnostics; Alaudidae; biometric data; Biometrics; delineating subspecies; discriminant function analysis; geographic variation; Morphology
• ISSN: 0030-6525; 1727-947X
• DOI: 10.2989/00306525.2016.1216016

Separation of the eight southern African subspecies of Sabota Lark Calendulauda sabota into thick-billed and slender-billed groups has been proposed. This study used biometric data obtained from museum skins in South Africa to evaluate morphological variation in the subspecies as a basis for the delineation of Sabota Lark into the thick-billed, slender-billed and intermediate groups. Six mensural characters were measured by a single researcher. Box plots were used to identify outliers, the 75% rule for diagnostics was applied to determine whether subspecies were distinct, and discriminant function analysis was used to evaluate the validity of the thick- and slender-billed groups, and the existence of a putative intermediate group. The results of this study support the separation of Sabota Lark into slender-billed (C.s. sabota, C.s. sabotoides, C.s. suffusca and C.s. waibeli) and thick-billed (C.s. bradfieldi, C.s. herero and C.s. naevi) groups based on culmen-nare length and bill width. The results failed to provide evidence for an intermediate group. Some C.s. ansorgei specimens had thick-billed characteristics, whereas others had slender-billed characteristics, implying sympatry of the thick- and slender-billed groups in southern Angola and north-western Namibia.