Morphology of the External Nose in <i>Hipposideros diadema</i> and <i>Lavia frons</i> with Comments on Its Diversity and Evolution among Leaf-Nosed Microchiroptera

Abstract

In some bats, a noseleaf is thought to help focus echolocation calls emitted through the nostrils. I studied the ontogenetic mode of the rhinarial cartilages and the associated facial muscles to assess how these rhinarial infrastructures interact with the noseleaf, and the inferred function of such a rhinarial complex. This study focuses on developmental stages of Hipposideros diadema and Lavia frons. Based on new data on these two rhinolophoids and a review of former studies concerning rhinopomatids, rhinolophoids and phyllostomids, the functional and phylogenetic implications of the rhinarial complex among leaf-nosed Microchiroptera are evaluated by the current study. Nasal emitting forms evolved several times independently in the Microchiroptera and share various features, irrespective of their phylogenetic position: the nostrils lie dorsally; the noseleaf has a well-developed horseshoe-shaped plate; the cartilago cupularis bears a large processus cupularis; M(iv) is extended on the lateral plate of the processus alaris superior. The unique similarities of the ontogenetic process of the nasal ‘resonators’ support the assumption that the rhinolophids + megadermatids and rhinopomatids may represent a natural group. In some features, the rhinolophids + megadermatids differ significantly from the phyllostomids. The noseleaf has a median flap and anterior-facing pockets. The processus alaris superior is half-tube-shaped or included in the lateral wall of the cupula nasi anterior. The cartilago accessoria and the attendant musculature perform an important function for supporting and moving the noseleaf. Similar emission of the echolocation pulses but alternative constructional designs of the external nose structures suggest that a separate history of rhinolophoids and phyllostomids might account for these differences.

Dynamic Substrate for the Physical Encoding of Sensory Information in Bat Biosonar

“…Along with the dynamic changes to the interface shapes, changes to the emission beampatterns during natural biosonar behaviors have been reported, but the underlying acoustic mechanisms remain unclear [18]. Evidence from several sources supports the hypothesis that the shape changes in the biosonar interfaces play a functional role: (i) the shape changes are effected by elaborate muscular actuation mechanisms [16,19], (ii) bats control the dynamic shape configuration sequences based on behavioral context [14,16], (iii) shape deformations coincide with ultrasonic diffraction in time [14,15], (iv) the magnitudes of the shape changes are significant compared to the transmitted wavelength [14,15,17]. In accordance with (iv), noseleaf and pinna deformations in horseshoe bats have been predicted to produce qualitative beampattern changes [15,17,20].…”

Normal embryonic development of the greater horseshoe bat Rhinolophus ferrumequinum, with special reference to nose leaf formation

“…Three muscles: the musculus nasolabialis profundus pars anterior, the musculus nasalis pars transversa, and “the noseleaf muscle” sensu Göbbel () are detected at the domain between the forehead (Figure C, c) and the upper lip beneath the nose leaf of R. ferrumequinum (Figure D, d). “The noseleaf muscle” and the musculus nasalis pars transversa are located within the connective tissue inside the posterior leaf.…”

“…Normal embryonic development has been described in three nose leaf possessing bat species belonging to two distinct lineages: Carollia perspicillata belonging to the family Phyllostomidae (Cretekos et al, ) and Hipposideros armiger and Hipposideros pratti belonging to the family Hipposideridae (Wang, Han, Racey, Ru, & He, ). In addition, internal tissue morphology of the nose‐leaves has been investigated through histological analyses of late‐stage fetuses of Rhinopomatid, Megadermatid, Hipposiderid, and Phyllostomid bats (Göbbel, , ). Göbbel (, ) created 3D‐models of the rhinarial cartilages of nose leaf possessing bat species based on reconstruction of histological sections.…”

“…In addition, internal tissue morphology of the nose‐leaves has been investigated through histological analyses of late‐stage fetuses of Rhinopomatid, Megadermatid, Hipposiderid, and Phyllostomid bats (Göbbel, , ). Göbbel (, ) created 3D‐models of the rhinarial cartilages of nose leaf possessing bat species based on reconstruction of histological sections. She also described morphology of the muscles inside the nose leaf and named the muscles.…”

Quantitative approaches to sensory information encoding by bat noseleaves and pinnae

“…These shape changes are driven by specialized musculatures (Schneider and Möhres 1960;Schneider 1961;Göbbel 2002) and are known to occur during pulse emission (for the noseleaf (Feng et al2012;He et al 2015)) or echo reception (for the pinnae (Yin et al 2015)). Noseleaf and pinna motions are fast and occur on a similar time scale as the durations of the biosonar pulses and echoes (Gao et al 2011;Feng et al 2012;He et al 2015).…”