Extraordinary Local Diversity of Disk-Winged Bats (Thyropteridae:Thyroptera) in Northeastern Peru, with the Description of a New Species and Comments on Roosting Behavior

Hershkovitzia (Diptera: Nycteribiidae): revision, phylogeny, and cophylogeny

Hershkovitzia Guimares & DAndretta, 1956 belongs to Nycteribiidae (Diptera), a family of hematophagous and obligate ectoparasites of bats. Hershkovitzia parasitize bats in the Thyropteridae family, which includes only one genus, Thyroptera Spix, 1823. Hershkovitzia species mostly have a one-to-one association pattern with their hosts, except for H. cabala Peterson & Lacey, 1985 and Hershkovitzia autinoae sp. nov., which share the same host. A review is presented of the species known to date, i.e., H. primitiva Guimares & DAndretta, 1956, H. coeca Theodor, 1967, H. inaequalis Theodor, 1967, H. cabala, and H. mariae Hrycyna, Santos, Rbelo & Graciolli, 2022, and a new species, H. autinoae sp. nov., is described herein. A parsimony analysis of Hershkovitzia was carried out based on a matrix of morphological characters. A cophylogenetic analysis of these parasites and their hosts was performed using a phylogeny of Thyroptera based on a modified version of a previously-published character matrix. As a result, both Hershkovitzia and Thyroptera are monophyletic. Hershkovitzia was divided and organized into two morphological groups based on its phylogeny. As the host of H. coeca is not known, five hypothetical coevolutionary scenarios were performed with each species of Thyroptera. For each coevolutionary scenario only one solution was generated, and all scenarios indicate that the hypothetical ancestor of Hershkovitzia emerged together with the hypothetical ancestor of Thyroptera. An identification key to Hershkovitzia species is presented together with schematic drawings of the abdomen, head, and legs of each species.

Humans as inverted bats: A comparative approach to the obstetric conundrum

OBJECTIVES

The narrow human birth canal evolved in response to multiple opposing selective forces on the pelvis. These factors cannot be sufficiently disentangled in humans because of the limited range of relevant variation. Here, we outline a comparative strategy to study the evolution of human childbirth and to test existing hypotheses in primates and other mammals.

METHODS

We combined a literature review with comparative analyses of neonatal and female body and brain mass, using three existing datasets. We also present images of bony pelves of a diverse sample of taxa.

RESULTS

Bats, certain non-human primates, seals, and most ungulates, including whales, have much larger relative neonatal masses than humans, and they all differ in their anatomical adaptations for childbirth. Bats, as a group, are particularly interesting in this context as they give birth to the relatively largest neonates, and their pelvis is highly dimorphic: Whereas males have a fused symphysis, a ligament bridges a large pubic gap in females. The resulting strong demands on the widened and vulnerable pelvic floor likely are relaxed by roosting head-down.

CONCLUSIONS

Parturition has constituted a strong selective force in many non-human placentals. We illustrated how the demands on pelvic morphology resulting from locomotion, pelvic floor stability, childbirth, and perhaps also erectile function in males have been traded off differently in mammals, depending on their locomotion and environment. Exploiting the power of a comparative approach, we present new hypotheses and research directions for resolving the obstetric conundrum in humans.

Specialized landing maneuvers in Spix's disk-winged bats (Thyroptera tricolor) reveal linkage between roosting ecology and landing biomechanics

Disk-winged bats (Thyroptera spp.) are the only mammals that use suction to cling to smooth surfaces, having evolved suction cups at the bases of the thumbs and feet that facilitate attachment to specialized roosts: the protective funnels of ephemeral furled leaves. We predicted that this combination of specialized morphology and roosting ecology is coupled with concomitantly specialized landing maneuvers. We tested this prediction by investigating landings in Thyroptera tricolor using high-speed videography and a force-measuring landing pad disguised within a furled leaf analogue. We found that their landing maneuvers are distinct among all bats observed to date. Landings comprised three phases: 1) approach, 2) ballistic descent, and 3) adhesion. During approach, bats adjusted trajectory until centered in front of and above the landing site, typically the leaf's protruding apex. Bats initiated ballistic descent by arresting the wingbeat cycle and tucking their wings to descend toward the leaf, simultaneously extending the thumb-disks cranially. Adhesion commenced when the thumb-disks contacted the landing site. Significant body reorientation occurred only during adhesion, and only after contact, when the thumb-disks acted as fulcra about which the bats pitched 75.02±26.17° (mean±s.d.) to swing the foot-disks into contact. Landings imposed 6.98±1.89 bodyweights of peak impact force. These landing mechanics are likely influenced by the orientation, spatial constraints, and compliance of furled leaf roosts. Roosting ecology influences critical aspects of bat biology, and taken as a case-study, this work suggests that roosting habits and landing mechanics could be functionally linked across bats.

First records of Thyroptera lavali (Chiroptera, Thyropteridae) for the Guiana Shield with an updated distribution of Thyroptera species in Venezuela

The genus Thyroptera is composed of small insectivorous bats widely distributed in the Neotropics. Thyroptera lavali is an Amazonian species distributed in lowland rainforests of Peru, Ecuador and Brazil and in the Venezuelan Eastern Llanos. The goal of this study was to document new records of T. lavali for Venezuela and update the geographic distribution of Thyroptera species in that country. Based on specimens deposited in Venezuelan museums, we report the first record of T. lavali for the Guiana Shield and the second record for the Venezuelan Llanos. The external and cranial measurements of the analyzed specimens fall within the range previously reported for T. lavali; likewise, the qualitative characters are similar to what is known for the species. Additionally, derived from a search of records in databases, we report the first specimens of Thyroptera discifera for the Orinoco river basin. We confirm the presence of three species in Venezuela: T. discifera, distributed in the Cordillera de la Costa and Central and Western Llanos; Thryoptera tricolor, occurring in the Andes, Deltaic System and the Guiana Shield and T. lavali, recorded in the Eastern Llanos, Deltaic System and the Guiana Shield.

Vertical stratification in bat assemblages of the Atlantic Forest of south-eastern Brazil

Tropical forests are three-dimensional spaces with species and resources heterogeneously distributed. The vertical stratification of tropical forest biotas has been observed for several organisms and regions, but, surprisingly, the vertical structuring of large areas of important tropical forests, such as Brazil's Atlantic Forest, remains poorly studied. Here, we addressed the use of different Atlantic Forest strata by bats, comparing ensemble composition and relative abundance between the understorey and the canopy. A total of 618 bats belonging to 31 species and four families were recorded, including 11 species of frugivores and seven species of gleaning insectivores, the two trophic guilds predominantly represented in our sampling. Fifteen species were captured exclusively in the canopy, and six exclusively in the understorey, and many of those species were represented by a low number of captures (<5). The bat species composition, richness and relative abundance between canopy and understorey strata varied.Chiroderma villosumwas exclusively captured in the canopy,Artibeus lituratuswas netted predominantly in the canopy andCarollia perspicillataandDesmodus rotunduswere mostly captured in the understorey. Although processes such as resource partitioning between species and ecomorphological constraints may explain the differential use of forest strata, this remains little understood because of the scarcity of data for the Atlantic forest canopies.

Small mammals (Chiroptera, Didelphimorphia, and Rodentia) from Jaíba, middle Rio São Francisco, northern Minas Gerais State, Brazil

We report the results of small mammals inventories conducted in the region of Jaíba, northern Minas Gerais state, southeastern Brazil, from 1990 to 1995. This region is located in the southern limit of the Caatinga biome, and harbors a unique set of natural ecosystems and extensive agricultural areas. With a total effort of 2964 trap-nights and 44 net sessions, we captured 893 small mammals from 46 species, including four marsupials, 13 rodents, and 29 bats. We report on species that are endemic to the Caatinga (Wiedomys pyrrhorhinos and Xeronycteris vieirai), and species that are new to the mammal fauna of the state of Minas Gerais (Tonatia saurophila, X. vieirai, and Myotis lavali). We also provide the first valid voucher-supported record of Micronycteris sanborni from southeastern Brazil, and extend the known range of X. vieirai 800 km southward. All bats highlighted here as endemic or representing new records were associated to limestone outcrops, suggesting that preservation of this kind of habitat may be particularly relevant to the conservation of these mammals.