Evolution of a sensory cluster on the legs of Opiliones (Arachnida) informs multi-level phylogenetic relationships

Author(s)

Gainett, Guilherme ^{[1, 2, 3]} ; Sharma, Prashant P. ^[2] ; Fernandes, Nathalia ^[3] ; Pinto-Da-Rocha, Ricardo ^[3] ; Giribet, Gonzalo ^{[4, 5]} ; Willemart, Rodrigo Hirata ^{[1, 6, 3]}

Affiliation

^[1] Univ Sao Paulo, Escola Artes Ciencias & Humanidades, Lab Ecol Sensorial & Comportamento Artropodes, Rua Arlindo Bettio 1000, BR-03828000 Sao Paulo, SP - Brazil

^[2] Univ Wisconsin Madison, Dept Integrat Biol, 430 Lincoln Dr, Madison, WI - USA

^[3] Univ Sao Paulo, Inst Biociencias, Programa Pograd Zool, Rua Matao 321, Travessa 14, BR-05508090 Sao Paulo, SP - Brazil

^[4] Harvard Univ, Museum Comparat Zool, Cambridge, MA 02138 - USA

^[5] Harvard Univ, Dept Organism & Evolutionary Biol, Cambridge, MA 02138 - USA

^[6] Univ Fed Sao Paulo, Programa Posgrad Ecol & Evolucao, Campus Diadema, Rua Prof Artur Riedel 275, BR-09972270 Diadema, SP - Brazil

• Document type: Journal article
• Source: ZOOLOGICAL JOURNAL OF THE LINNEAN SOCIETY; v. 187, n. 1, p. 143-165, SEP 2019.
• Web of Science Citations: 0

Abstract

Phylogenetic relationships in Opiliones (Arachnida) at the suborder level have greatly stabilized in recent years, largely due to advances in molecular systematics. Nonetheless, identifying morphological characters in the context of well-resolved phylogenies is essential for testing new systematic hypotheses and establishing diagnostic markers. Here, we investigate with SEM a promising character system across Opiliones: the sensilla on the distalmost article of legs I and II. We identified four discrete characters and scored species of nearly all families of Laniatores (28 families, 44 species), three Dyspnoi, two Eupnoi and two Cyphophthalmi. Using a phylogenetic backbone compiled from recent and ongoing phylogenomic studies, we trace the evolution of these sensilla using ancestral state reconstruction. We discover a widespread occurrence of three sensilla (a pair of sensilla basiconica and one hooded sensillum) on the anterior legs of all families of Laniatores studied, and that comparable structures occur in the other suborders of Opiliones. Our analysis shows that this sensory field provides diagnostic information at different levels of phylogenetic relationships. We discuss the implications of the widespread occurrence of these sensilla in Opiliones, which have recently been hypothesized as hygro-/thermoreceptors and their putative homology with tarsal organs in Arachnida. (AU)

• FAPESP's process: 10/00915-0 - Chemical communication in harvestmen (Arachnida, Opiliones): morphology, behavior and chemistry
• Grantee: Rodrigo Hirata Willemart
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 13/23189-1 - Fine morphology of the putative olfactory hairs in the harvestman Heteromitobates discolor (Arachnida: Opiliones: Laniatores)
• Grantee: Guilherme Gainett Cardoso Martins de Carvalho Florez
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 13/50297-0 - Dimensions US-BIOTA São Paulo: a multidisciplinary framework for biodiversity prediction in the Brazilian Atlantic forest hotspot
• Grantee: Cristina Yumi Miyaki
• Support Opportunities: BIOTA-FAPESP Program - Thematic Grants
• FAPESP's process: 14/07671-0 - Ultrastructure of sensilla chaetica in the harvestman Heteromitobates discolor (Arachnida: Opiliones: Laniatores)
• Grantee: Guilherme Gainett Cardoso Martins de Carvalho Florez
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• FAPESP's process: 15/01518-9 - Morphology, systematics, chemistry and behaviors related to glands and chemoreceptors in laniatorid harvestmen (Arachnida, Opiliones)
• Grantee: Rodrigo Hirata Willemart
• Support Opportunities: Regular Research Grants