Extreme bill dimorphism leads to different but overlapping isotopic niches and similar trophic positions in sexes of the charismatic extinct huia

The New Zealand huia (Heteralocha acutirostris) had the most extreme bill sexual dimorphism among modern birds. Given the quick extinction of the species, the cause of the dimorphism could only be hypothesised to reflect different trophic niches and reduce male/female competition. We tested that hypothesis by combining museum specimens, geometric morphometrics, and isotopic analyses. We used geometric morphometrics to describe bill shape; measured bulk (δ15Nbulk) and (δ13Cbulk) values from feather as proxies of the birds’ foraging habitat and diet; and compared compound-specific stable isotopes analyses (CSIA) of nitrogen in amino acids (δ15NAA) in male–female pairs to estimate their trophic position. Sexes had significantly different, but overlapping feather δ15Nbulk and δ13Cbulk values, but δ15NAA indicated identical trophic positions and δ15Nbulk was not related to bill shape. Trophic position was less variable among females, consistent with a specialised foraging behaviour and, thus, supporting a partial male/female foraging segregation.

Rapid phenotypic change in a polymorphic salamander over 43 years

Color polymorphic animals offer a unique system for studying intraspecific phenotypic responses to climate change. Discrete color morphs are easy to identify, and correlated trait responses of morphs can indicate how climate warming may facilitate long-term maintenance of polymorphisms. We use a historical dataset spanning 43 years to examine temporal shifts in color morph frequency and body size in response to climate in the Eastern Red-backed Salamander, Plethodon cinereus, which contains a widespread striped/unstriped color polymorphism. We created a pipeline to extract high-throughput trait data from fluid-preserved museum specimens where we batch-photographed salamanders, de-aggregated individual specimens from photographs, and solicited help of community scientists to score color morphs. We used a linear modeling framework that includes information about spatial population structure to demonstrate that color morph frequency and body size vary in response to climate, elevation, and over time, with an overall trend of higher frequency and decreased body size of the striped morph, but increased size of the unstriped morph. These surprising results suggest that morphs may be responding to multiple climate and geographic drivers through co-adapted morphological changes. This work highlights new practices of extracting trait data from museum specimens to demonstrate species phenotypes response to climate change.

Redescription of the genus Megastilicus Casey (Staphylinidae, Paederinae) with the description of a new species

The myrmecophilous Paederinae rove beetle genus Megastilicus Casey, 1889 from North America is reviewed based on museum specimens. Prior to this study, the genus was monotypic with one species Megastilicus formicarius Casey, 1889 described. Here, we provide a redescription of the genus and the type species, designate a lectotype, and provide pictures of habitus and illustrations of the aedeagus and genital segments. Additionally, we describe a new species for the genus, Megastilicus iowaensis sp. nov., include an identification key to the two species and present the distribution map of both of them, including new state records. We discuss the assignment of the genus to the subtribe Stilicina based on morphological features.

Mitogenome of the Extinct Desert ‘Rat-Kangaroo’ Times the Adaptation to Aridity in Macropodoids

The evolution of Australia’s distinctive marsupial fauna has long been linked to the onset of continent-wide aridity. However, how this profound climate change event affected the diversification of extant lineages is still hotly debated. Here, we assemble a DNA sequence dataset of Macropodoidea — the clade comprising kangaroos and their relatives — that incorporates a complete mitogenome for the Desert ‘rat-kangaroo’, Caloprymnus campestris. This enigmatic species went extinct nearly 90 years ago and is known from a handful of museum specimens. Caloprymnus is significant because it was the only macropodoid restricted to extreme desert environments, and therefore calibrates the group’s specialisation for increasingly xeric conditions. Our robustly supported phylogenies nest Caloprymnus amongst the bettongs Aepyprymnus and Bettongia. Dated ancestral area optimisations further reveal that the Caloprymnus-Bettongia lineage originated in nascent arid zone settings from the later-middle to early-late Miocene, ~12 million years ago (Ma), but subsequently dispersed into mesic habitats during the Pliocene and Pleistocene. This coincides with ancestral divergences amongst kangaroos in disparate woodland-forest and shrubland settings, but predates their adaptive radiation into proliferating grasslands during the late Miocene to Pliocene, after ~7 Ma. We thus demonstrate that protracted changes in both climate and vegetation likely staged the emergence of modern arid zone macropodoids.

Deducing how tropical rhyssines (Hymenoptera, Ichneumonidae) mate from body measurements

The biology of many Darwin wasp (Hymenoptera: Ichneumonidae) species is poorly known. Existing museum specimens can potentially be used to get information on e.g. how species live, what they eat, and what their life cycle is. One example of this is a 1991 study by Eggleton in which he measured some rhyssine (Ichneumonidae: Rhyssinae) species, and used the results to deduce how the species likely mate. We extend this work by measuring five tropical species. We found no evidence that the males of our species scramble for females before the females emerge, which matches what was hypothesised by Eggleton. Further measurements of more species would provide information on how other species mate, and field observations of mating rhyssines would help confirm that Eggleton’s method for deducing rhyssine mating strategies gives true results.

Ten new species of marine bryozoans (Gymnolaemata: Cheilostomatida) from Brazil

Despite a recent increase in the number of taxonomic studies on the bryozoan fauna of northeastern Brazil, new discoveries and re-examination of museum specimens allow the continued recognition of new taxa. Here, we describe ten new cheilostome species from the northeastern continental shelf of Brazil based on different museum collections. The new species are: Thalamoporella tupinamba n. sp., Turbicellepora papula n. sp., Plesiocleidochasma brasiliensis n. sp., Plesiocleidochasma infundibulum n. sp., Rhynchozoon turgidum n. sp., Cribrilaria brasiliensis n. sp., Hippoporina titan n. sp., Crepidacantha fasciata n. sp., Crepidacantha browni n. sp., and Hippopodina inarmata n. sp. Some specimens previously reported from northeastern Brazil are here reassigned to the newly described taxa, and two new combinations, Cribrilaria caraguata (Winston & Vieira, 2013) n. comb. and Cribrilaria tuba (Winston & Vieira, 2013) n. comb., are proposed.

Mating marks on museum specimens reveal breeding patterns in species of Pterostichus Bonelli (Carabidae, Pterostichini)

We found distinct and consistently placed, species- and sex-specific abrasions of the cuticle on museum specimens of 14 species of the Pterostichus Bonelli, 1810 (Carabidae, Pterostichini) subgenus Hypherpes Chaudoir, 1838. We deduced that these marks are generated during mating and, therefore, can be used to distinguish between preserved specimens of beetles that had previously mated at the time of capture and those that had not mated. In addition to describing and detailing the occurrence of the marks and providing evidence that they are the result of mating, we demonstrate their utility for inferring life history using a museum voucher collection. By scoring these indications of mating from pinned specimens, we describe life cycle patterns in two similar, relatively closely related and sympatric species of the subgenus Hypherpes, P. vicinus Mannerheim, 1843 and P. californicus (Dejean, 1828). Both were sampled during a pitfall trap study in Contra Costa, California, USA from 2014–2019 and deposited in the Essig Museum of Entomology, UC Berkeley. Both species had very low adult activity through the drought and end of drought period prior to the spring of 2017 and are significantly more abundant in the post-drought period. Based on mating marks, both species responded to accumulated precipitation ending the drought by the emergence of an active, mostly unmated cohort of adults. The spring activity peak, following the end of the drought, was dominated by unmarked and presumably unmated beetles, but samples from subsequent springs included a nearly equal mix of beetles showing mating marks and apparently unmated beetles. The beetle activity appears to correspond more with the accumulated rainfall of the preceding rainy season than with the rains of the sample year. Beetles sampled in autumn and winter (rainy season) predominantly show mating marks. The occurrence throughout the year of beetles that are marked as having mated is consistent with iteroparous beetles with a lifespan of more than one year and also consistent with dynamic phenotypic polyvariance in which the adult activity period is synchronised by adjusting development time. The dominant pattern fits with a life cycle that is typically annual univoltine, or possibly biennial semivoltine in dry years, rainy season breeding (autumn-winter) iteroparous, with adult summer aestivation and possibly facultative larval hibernation. However, unmarked and so apparently unmated individuals and teneral adults were captured during peak activity periods regardless of the season, suggesting that either the beetles diapause as teneral adults that then complete development and become active at various points during the year and/or there are multiple periods of breeding and oviposition each year in at least some portion of the population.

Systematics of the Arboreal Neotropical ‘thorellii’ Clade of Centruroides Bark Scorpions (Buthidae) and the Efficacy of Mini-Barcodes for Museum Specimens

Fragmented and degraded DNA is pervasive among museum specimens, hindering molecular phylogenetics and species identification. Mini-barcodes, 200–300-base-pair (bp) fragments of barcoding genes, have proven effective for species-level identification of specimens from which complete barcodes cannot be obtained in many groups, but have yet to be tested in arachnids. The present study investigated the efficacy of mini-barcodes combined with longer sequences of the Cytochrome c Oxidase Subunit I (COI) gene in the systematics of the arboreal Neotropical ‘thorellii’ clade of Centruroides Marx, 1890 bark scorpions (Buthidae, C.L. Koch 1837), the species of which have proven to be difficult to identify and delimit due to their similar morphology. The phylogeny of 53 terminals, representing all nine species of the clade and representative species belonging to related clades of Centruroides, rooted on Heteroctenus junceus (Herbst, 1800) and based on up to 1078 base pairs of COI and 112 morphological characters, is presented to test the monophyly of the clade and the limits of its component species. The results support the recognition of nine species of the ‘thorellii’ clade, in accordance with a recent taxonomic revision, and highlight the efficacy of mini-barcodes for identifying morphologically similar cryptic species using specimens of variable age and preservation.