A Phylogenetic Hot Spot for Evolutionary Novelty in Middle American Treefrogs

Abstract

Among the various types of evolutionary changes in morphology, the origin of novel structures may be the most rare and intriguing.Here we show statistically that the origins of different novel structures may be correlated and phylogenetically clustered into "hot spots" of evolutionary novelty, in a case study involving skull elements in treefrogs. We reconstruct phylogenetic relationships and with the evolution of a novel adaptive behavior. Our study may be the first to statistically document significant phylogenetic clustering and correlation in the origins of novel structures, and to demonstrate the strongly misleading effects of peramorphosis on phylogenetic analysis.

The Green Clade grows: A phylogenetic analysis of Aplastodiscus (Anura; Hylidae)

“…DNA extraction, amplification, and sequencing methods are those described by Blotto et al (2013). The COI primers are those of Jungfer et al (2013), the TNS3 primers are of Smith et al (2007), and the remaining primers used are those of Faivovich et al (2013). See Appendix A for voucher data and the GenBank access numbers of sequences employed in this study.…”

A new species of casque-headed tree frog, genus Aparasphenodon Miranda-Ribeiro (Amphibia: Anura: Hylidae), from the Atlantic Rainforest of southern Bahia, Brazil

“…The main problem to morphologically define a clear distinction between Aparasphenodon and Triprion by means of Duellman's (2001) phylogenetic hypothesis is that the author did not consider South-American species in his analysis, and thus we do not have extensive information about these character states among the latter. Yet, the expanded maxillae of the new species may be another parallelism (homoplasy) related to the phragmotic behavior of casque-headed tree frogs to their microhabitat usage, as demonstrated by Smith et al (2007) for other skull roof bones of casque-headed hylids (see above).…”

“…However, prenasal bones are also observed in other casque-headed hylids, as in the genus Triprion Cope, 1866 (Duellman, 2001). Recently, Smith et al (2007) re-analyzed phylogenetically the casque-headed hylids of Middle America (Anotheca Smith, 1939;Pternohyla Boulenger, 1882;Smilisca Cope, 1865;and Triprion) by both molecular and morphological approaches, and also included an additional phylogenetic analysis for the hylid frogs of Lophiohylini. In Lophiohylini, the prenasal evolved once (in Aparasphenodon, thus homoplastic to prenasal of the Middle American genus Triprion) and gained a dermal sphenethmoid four different times (which in turn is homoplastic within Lophiohylini, and also to the Middle American genera Triprion and Diaglena Cope, 1887).…”

“…This scenario shows that novel cranial elements (non apomorphic modifications of pre-existing structures), like that present on the skull roof of casque-headed hylids (e.g., dermal sphenethmoid, prenasal, and internasal), have evolved in parallel within these hylids as a whole. Yet, Smith et al (2007) results pointed out that these novel elements are associated to phragmotic behavior (using the head to plug burrows), which suggests that they may have adaptive functional and ecological significance, which in turn favors the development of such structures by parallelism (homoplasy). In this sense, we understand that the presence of a prenasal bone is insufficient to morphologically allocate the new species to Aparasphenodon, Triprion, or Diaglena.…”

Discovery of an Internasal Bone in <I>Hynobius maoershanensis</I> (Urodela: Hynobiidae)

“…In Latimeria chalumnae, a rare "living fossil", internasal bones are also present, of which the number, shape and position are the same as those in Eusthenopteron (Zhang, 1986). In a hylid frog, Smilisca fodiens, an internasal bone presents anterior and dorsal to the premaxillae (Trueb, 1970;Smith et al, 2007). However, the internasal bone has also been regarded as an unreliable character for other species.…”