Two new aphrotenian larval types from Chile and Queensland, including Anaphrotenia lacustris n.gen., n.sp (Diptera: Chironomidae)

• Published in: Insect Systematics & Evolution
• Main Author: Brùndin, Lars
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Brill 1983
• Subjects: Insect Science; Ecology; Ecology, Evolution, Behavior and Systematics; Antarctic; Queensland; Fraser Island; Antarc*
• Online Access: http://dx.doi.org/10.1163/187631283x00182; https://brill.com/view/journals/ise/14/4/article-p415_7.xml; https://brill.com/downloadpdf/journals/ise/14/4/article-p415_7.xml

Abstract Two as yet unknown larvae of the circum-Antarctic subfamily Aphroteniinae, one belonging to Paraphrotenia cf. excellens Brundin, the other representing the new genus and species Anaphrotenia lacustis, are described. While the other members of the subfamily are confined to mountain streams, the larva of anaphrotenia has been found in the littoral zone of a shallow subtropical lake on Fraser Island off the coast of Queensland. Besides some peculiar specializations this larva attracts interest because of the primitive construction of the head capsule where the genae ventrally are widely separated and the wide medial interspace is occupied by a longitudinal postmental plate that is not fused with the genal margins. In these respects the Anaphrotenia larva stands out as the most plesiomorphic chironomid larva as yet known; and it comes probably rather close to the larva of the dipteran ancestor. With its closed head capsule and specialized mouth parts the predatory Paraphrotenia larva appears much more apomorphic. But it retains several comparatively plesiomorphous characters, and among the predatory species of the chironomid larvae it represents a very remarkable type. In both genera the crop is developed as a diverticulum from the oesophagus. The presence of a special, sac-like grinding mill at the caudal end of the crop in both genera seems to be unique. — The paper ends with a discussion on a comparative basis of some aphrotenian larval characters and their anagenetic status. Special attention is paid to the mentum and the development of ventromental and dorsomental teeth within Chironomidae. Also discussed is the independent development of predatory habits and their combination with special morphological traits within different monophyletic groups. Of special interest is the comparatively late occurrence of such habits and corresponding morphological traits high up in the chironomid hierarchy within the Harnischia-group, a phenomenon that is believed to be a case of evolutionary reversal.