Chinook salmon (<Emphasis Type="Italic">Oncorhynchus tshawytscha</Emphasis>, Walbaum 1792) in the Beagle Channel,Tierra del Fuego: the onset of an invasion

In this paper we provide the first report of the presence of exotic Chinook salmon (Oncorhynchus tshawytscha) in two rivers off the Beagle Channel, Lapataia and Ovando, in southern Tierra del Fuego. We also confirm that successful reproduction occurred in the fall of 2007, as we captured yearlings in freshwater. Scale pattern analyses of adult fish caught were all of the “stream” ecotype, with ages ranging between 3 and 5 (average 4.2 year). Stable isotope analysis of Ovando-Lapataia Chinook population indicates general patterns consistent with those of other populations in the region, but characteristically enriched levels of C indicates a distinct ocean feeding location as compared to Atlantic populations in the Santa Cruz River. Two different haplotypes, one identical to the unique haplotype of the Caterina River population, were found in the Ovando-Lapataia rivers, providing partial evidence for some level of contemporary segregation between these two populations. As an exotic species, Chinook salmon have been able to use the ocean as a waterway to rapidly colonize new habitats both in New Zealand and in several Pacific and Atlantic river basins of continental Patagonia. This record expands the known distribution of this species in Patagonia further south and into the Island of Tierra del Fuego. Its presence in the Beagle Channel creates the conditions for its expansion to a significant collection of new rivers, as well as to adjacent marine areas in and around the Southern Fuegian Channels. Our results provide support to the idea that, in practice, no district of Patagonia is sheltered from the colonization by invasive anadromous Salmonids.     

First Quaternary fossil record of Polyplacophorans from southern South America

A diverse assemblages of well-preserved polyplacophoran shell plates is present in Holocene marine deposits along the Beagle Channel, Tierra del Fuego (54°S). They represent the first fossil Quaternary report of polyplacophorans from southern South America. The taxa include Callochiton puniceus (Couthouy MS, Gould), Plaxiphora aurata (Spalowsky), Plaxiphora sp., Tonicia atrata (Sowerby), Tonicia calbucensis Plate, Tonicia chilensis (Frembly), and Tonicia lebruni de Rochebrune. The presence of these taxa in a transitory area between the Atlantic and the Pacific oceans suggests that, in the recent past, the Beagle Channel acted as a path that facilitated faunal dispersion between the two oceans. These records also show an apparent stability of these faunas over a period of several thousand years (from ca. 7500 years BP to present).     

Parasite-mediated shell alterations in Recent and Holocene sub-Antarctic bivalves: the parasite as modeler of host reaction

Abstract. New data on shell reactions elicited by larval digeneans in bivalves from Recent sub-Antarctic populations and late Holocene Patagonian deposits are reported. Shell alterations, which are traces of digenean trematode infections, were found affecting intertidal bivalve populations from Malvinas (Falkland) Islands, Burdwood Bank, Beagle Channel, and from Holocene deposits at Tierra del Fuego (Argentina). The bivalve species involved belonged to the families Nuculanidae, Cyamiidae, and Neoleptonidae. Such reactions consisted of quite unusual dome or igloo-shaped calcifications on the inner shell surface; the similarities and uniqueness of this reaction in different bivalve species reported here suggest that the invasive agent is the same. Based on previous findings of morphologically identical shell alterations in Gaimardia trapesina (Bivalvia, Gaimardiidae) from Magellanic and sub-Antarctic waters, it is suggested that the parasites responsible for the traces reported here belong to a digenean platyhelminth species of the Gymnophallidae genus Bartolius . The host bivalves reported here belong to three different superfamilies, and share a similar crystalline shell microstructure: aragonite with homogeneous structure. After a review of the available information dealing with bivalve shell-mantle reactions against digeneans, it is hypothesized that parasites are responsible for the modeling of the host response they elicit. However, although the specific characteristics of the reaction depend on the parasite, they would probably be constrained by some characteristics of the host shell structure.     

Evidence of protandry in a subantarctic notothenid, Eleginops maclovinus (Cuv. & Val., 1830) from the Beagle Channel, Argentina

Gonads of Eleginops maclovinus (Cuv. & Val., 1830) from the Beagle Channel (Tierra del Fuego, Argentina) were sampled weekly throughout the year and histologically analysed. Gonads containing solely or mostly testicular tissue were predominant in each length class smaller than 40 cm (80 to 100%). Sex ratio was almost 1:1 in fishes ranging from 41 to 45cm. Females were dominant in specimens larger than 46cm (80 to 100%). Four testicular types are described according to maturation degree and absence or presence of female cells, one intermediate gonadal type and one typical ovarian type. It is concluded that this species is a protandrous hermaphrodite.     

The subtidal macrobenthic assemblages of Bahía San Sebastián (Tierra del Fuego,Argentina)

Bahía San Sebastián (BSS), a shallow and protected environment on the eastern coast of Tierra del Fuego (Argentina), is a prime habitat for several species of nearctic migratory birds that visit the area during summer to feed in its huge intertidal mudflats. The area has also great economic value due to the extraction and transport of hydrocarbons. Twenty-three dredge stations were analysed and presence/absence data were used to classify stations and species by cluster analysis. Two algae and 113 taxa of macrobenthic invertebrates from 12 animal phyla were identified. Species richness was one order of magnitude higher (mean 29.0 sp st⁻¹) in stations located outside or in the southern unprotected section of BSS than in most muddy or sandy stations within the bay (mean 3.7 sp st⁻¹). Hard bottom stations outside BSS were dominated by a rich assemblage of sessile filter-feeders, mainly bryozoans, hydrozoans, ascidians, sponges, and the bivalve Aulacomya atra. Soft bottom areas inside BSS were mainly populated by relatively few species of deposit-feeders, such as the orbiniid polychaete Phylo felix, which was particularly frequent and widespread. Shells of the clam Mulinia edulis are very common, representing one of the few hard substrata available for sessile species on soft bottoms. Epibenthic assemblages within BSS were dominated by the detritivorous isopod Serolis paradoxa and the crab Eurypodius latreillei. The macrobenthic fauna of BSS can be regarded as typical of the Magellan region, showing affinities with those of other localities around Tierra del Fuego, the Straits of Magellan and the southern Chilean fjords.     

Mitochondrial DNA variation and population structure of Commerson’s dolphins (<Emphasis Type="Italic">Cephalorhynchus commersonii</Emphasis>) in their southernmost distribution

The Commerson’s dolphin, Cephalorhynchus commersonii, is found in shallow waters of the continental shelf off the eastern coast of South America between 40°S and 56°S. This species is taken incidentally in artisanal gillnet fisheries, especially along the shallow coastline of northern Tierra del Fuego and southern Patagonia. The biological importance of by-catch is likely to be underestimated if the boundaries of subpopulations are not properly defined. Here, we report on the sequence variation of the mitochondrial DNA control region of the Commerson’s dolphin from five areas defined in Tierra del Fuego, Argentina and Chile, to provide a preliminary assessment of population structure where conservation efforts are most needed. A 466 bp fragment of the mitochondrial DNA control region was sequenced from 196 samples of skin, teeth and bone, defining 20 haplotypes from 17 polymorphic sites. Nucleotide (π = 0.40%) and haplotype (h = 0.807) diversity were low compared to some other odontocete populations, but similar to that of other species of this genus. Genetic differentiation evaluated through analyses of molecular variance (AMOVA) showed significant overall differences among areas within Tierra del Fuego (Φ _ST  = 0.059, P < 0.01). An analysis of sex-specific population structure suggested that the dispersal rates of both females and males are low, indicative of females displaying greater site fidelity. The results from mtDNA control region sequences alone revealed significant differentiation among studied areas, which should be considered as independent management units. We recommend that the impact of localized gillnet mortalities should be managed on a local scale in these areas of Tierra del Fuego.     

Historical ecology and current abundance of the translocated Chilla or Grey fox Lycalopex griseus on the large Tierra del Fuego Island shared by Argentina and Chile

In 1951, a batch of 24 young animals of both sexes of Chilla or Grey fox Lycalopex griseus from continental Magallanes region, Chile – and perhaps also from adjacent continental Argentina – were released at Onaisin (65 km ESE Porvenir town, 53°18′S) on Tierra del Fuego Island in southernmost South America, to control a European rabbit (Oryctolagus cuniculus) irruption that was considered detrimental to sheep (Ovis aries) ranching. Up to now, no attention has been paid to the temporal course of that introduction. Here we provide a historical account of the presence of foxes on the Tierra del Fuego Archipelago, starting with Charles Darwin account of 1839 until present. We also review the regulatory framework concerning hunting of those foxes and tally their culling for export of pelts. Finally, we provide estimates of the abundance of Chilla foxes on Tierra del Fuego Island for the period 1999–2007 and for 2021, and highlight their current spread. These translocated foxes have become an abundant and functional part of both steppe and forest ecosystems on the Fuegian archipelago, even though they are killed by hunters, without spatial, temporal, or numerical limits. We conclude that interesting scientific opportunities are being missed regarding the population genetics of a species that may have left founding effects and genetic bottlenecks in Tierra del Fuego, and perhaps some peculiar continental markers among the island population. We also raise the question whether this introduced native species may be deemed invasive, calling for research to determine its impact in its new environment.     

A new species of Penicillium from the Chilean Tierra del Fuego

A new species of Penicillium is described and illustrated. It is represented by two isolates recovered from sandy soils on the shores of Lake Sarmiento, in the Chilean Tierra del Fuego. The new species clearly differs from all species of the genus described so far among the monoverticillate ones, especially by the unique wall ornamentation pattern as viewed with the SEM. It is therefore, described and proposed as a new taxon: Penicillium lacussarmientei sp. nov.     

Two new species of Penicillium from the Tierra del Fuego (Argentina and Chile)

Two new species of Penicillium Link ex Fries are described and illustrated. They were recovered from sandy soils in the Chilean and Argentinian Tierra del Fuego. They clearly differ from all species of the genus described so far and are, therefore, described and proposed as two new taxa: Penicillium turris-painensis sp. nov and Penicillium lapatayae sp. nov.     

Invaders Without Frontiers: Cross-border Invasions of Exotic Mammals

We address cross-border mammal invasions between Chilean and Argentine Patagonia, providing a detailed history of the introductions, subsequent spread (and spread rate when documented), and current limits of mammal invasions. The eight species involved are the following: European hare (Lepus europaeus), European rabbit (Oryctolagus cuniculus), wild boar (Sus scrofa), and red deer (Cervus elaphus) were all introduced from Europe (Austria, France, Germany, and Spain) to either or both Chilean and Argentine Patagonia. American beaver (Castor canadensis) and muskrat (Ondatra zibethicus) were introduced from Canada to Argentine Tierra del Fuego Island (shared with Chile). The American mink (Mustela vison) apparently was brought from the United States of America to both Chilean and Argentine Patagonia, independently. The native grey fox (Pseudalopex griseus) was introduced from Chilean to Argentine Tierra del Fuego. Few spread rates are available: the lowest are 10 km/yr and correspond to American beaver and American mink; intermediate rates are observed in muskrat and rather questionably, in grey fox; the highest rates (10–20 km/yr) are found among European hare and European rabbit. Because of their frequent migration, it is difficult to estimate the natural spread rate for wild boar and red deer. Not all mammal invasions in Chilean and Argentine Patagonia have been methodical advances of species; some involve an overlap of invasion fronts, with advances and retreats, and perhaps with re-invasions to different areas of either country. Because national policies with regard to introduced species may differ between countries sharing porous borders, it seems advisable to coordinate such policies in order to prevent the entry of unwelcome invaders.     

Annual gonadal cycle and reproduction in Patagonotothen tessellata (Richardson 1845 (Nototheniidae: Pisces) from the Beagle Channel, Argentina

The reproductive biology of Patagonotothen tessellata (Richardson 1845) in the Beagle Channel, Tierra del Fuego, Argentina was analysed from weekly captures over a 3-year period (1987–1989). The spawning periods and lengths thereof were analysed using GSI curves and monthly percentage distributions of maturation stages. Two gonadal maturation cycles and two spawning periods (winter and summer) within 1 year were defined. Also discussed is whether the same specimens are able to mate successfully in winter and summer, and whether the reproductive effort varies between the seasons. Male parental behaviour and the likely consequences on their energy levels are considered.     

Histological analysis of gonadal development in Patagonotothen tessellata (Richardson 1845) (Nototheniidae: Pisces) from the Beagle Channel, Argentina

Histological analysis of gonadal development in Patagonotothen tessellata (Richardson 1845) was carried out over a 3-year period (1987–1989) on samples from the Beagle Channel, Tierra del Fuego, Argentina. Testicular structure is defined as of the 'unrestricted spermatogonial type'. Maturation processes of cysts are synchronized in the various tubules. This degree of synchronization, as well as the characteristic of the different cellular types, permits definition of four spermatogenetic stages. Patagonotothen tessellata is defined as a total spawner according to ovocitary development and oocyte diameter frequency distribution analyses. Oocyte reabsorption and the likely consequences thereof on reproductive potential are also analysed. Patagonotothen tessellata is the first species of Nototheniids for which annual double spawning (winter and summer) and nonbiennial gonadal maturation processes are described.     

Assessing genetic variation and population structure of invasive North American beaver (<Emphasis Type="Italic">Castor Canadensis</Emphasis> Kuhl, 1820) in Tierra Del Fuego (Argentina)

The North American beaver (Castor Canadensis) was introduced into Isla Grande de Tierra del Fuego, Argentina in 1946 as a potential source of wild fur. The species showed high growth potential, reaching close to 100,000 individuals from an original founding stock of 25 females and 25 males. Beavers adapted rapidly to their new environment and became invasive, providing an excellent model of successful adaptation of introduced populations to a new habitat. In this study, we used polymorphic mitochondrial (mt) DNA to evaluate genetic variation in the introduced beaver population from Tierra del Fuego. Nucleotide variation in partial sequences of Cytochrome b (500 bp) and 12S rRNA (421 bp) genes and the main non-coding D-loop region (521 bp) were analyzed. Our study allowed to identify 10 different mtDNA lineages in the invasive population, none of them shared among the source populations. The pattern observed is a consequence of cessation of gene flow following expansion of the founding beaver population since the time of its introduction. This approach contributes to the understanding of effects of genetic changes on survival ability and reproductive success of invasive species. It also has important management implications to invasive species.     

Species-specific population trends detected for penguins,gulls and cormorants over 20 years in sub-Antarctic Fuegian Archipelago

Understanding the dynamics and causes of population trends are essential for seabird conservation. Long-term studies of seabirds at high-latitude (Antarctic, sub-Antarctic and Arctic) regions have shown contrasting species-specific trends in population size in response to climate change and anthropogenic pressures. We have studied for the last 20 years (1992–2012) the population trends of seven seabird species that breed in the Beagle Channel, south-eastern Tierra del Fuego and at Staten Island, a sub-Antarctic region in southern Argentina. The numbers of Magellanic and Gentoo Penguins increased significantly since 1992 (by >15 % year^?1). In comparison, the populations of Imperial Cormorants, Dolphin Gulls and Kelp Gulls increased at slower rates (<5 % year^?1), while the Rock Cormorant population even decreased by 1.3 % year^?1. At Staten Island, the numbers of Rockhopper Penguins decreased by 24 % between the censuses of 1998 and 2010, whereas the population of Magellanic Penguins increased by 227 % during the same period. Over the study period, air and sea-surface temperatures remained stable in our study area, suggesting that the detected population changes are not driven by the climate. This finding contrasts with the detected links between increasing temperature trends and seabird population changes reported from Antarctic and Arctic regions. The level of tourism and size of the permanent human population has increased in the Beagle Channel area during the last 20 years and could be responsible for the increase of gull populations. The seabird species that received the highest number of visitors (Imperial Cormorants and penguin species) seem to be adapted or at least indifferent to pressures exerted by tourism, as their populations increased during the study period. In addition, increasing numbers of seabirds in the area may generally be leading to higher abundances of scavenging species (e.g. gulls).     

Abundance and distribution of American beaver, Castor canadensis (Kuhl 1820), in Tierra del Fuego and Navarino islands, Chile

Castor canadensis specimens were imported from Canada and released in the wilderness on the Argentinean part of Tierra del Fuego (TDF) in the year 1946. First studies on the development of the beaver population and subsequent environmental changes were conducted four decades later and indicated a strong expansion of these animals, with negative effects on the forest, especially the dominant Nothofagus sp. Between 1999 and 2001, we investigated the density of the beaver population in the Chilean part of TDF and the southern adjacent island Navarino (NAV). Data were mapped into a geographical information system. The mean colony density was 1.03 (range: 0.15–1.91) and 1.1 per km watercourse for 75% of the area of TDF (mainly south and central region) and the total NAV island, respectively. The average number of individuals estimated per colony was five. Based on these findings, the number of beavers in the Chilean part of TDF and on NAV was estimated at 61,300 individuals. The population is increasing and expanding in the Northern region, with a linear rate of 2.6–6.3 km/year.     

Origin,diversity, and biogeography of Antarctic scale worms (Polychaeta: Polynoidae): a wide‐scale barcoding approach

The Antarctic marine environment hosts diversified and highly endemic benthos owing to its unique geologic and climatic history. Current warming trends have increased the urgency of understanding Antarctic species history to predict how environmental changes will impact ecosystem functioning. Antarctic benthic lineages have traditionally been examined under three hypotheses: (1) high endemism and local radiation, (2) emergence of deep‐sea taxa through thermohaline circulation, and (3) species migrations across the Polar Front. In this study, we investigated which hypotheses best describe benthic invertebrate origins by examining Antarctic scale worms (Polynoidae). We amassed 691 polynoid sequences from the Southern Ocean and neighboring areas: the Kerguelen and Tierra del Fuego (South America) archipelagos, the Indian Ocean, and waters around New Zealand. We performed phylogenetic reconstructions to identify lineages across geographic regions, aided by mitochondrial markers cytochrome c oxidase subunit I (Cox1) and 16S ribosomal RNA (16S). Additionally, we produced haplotype networks at the species scale to examine genetic diversity, biogeographic separations, and past demography. The Cox1 dataset provided the most illuminating insights into the evolution of polynoids, with a total of 36 lineages identified. Eunoe sp. was present at Tierra del Fuego and Kerguelen, in favor of the latter acting as a migration crossroads. Harmothoe fuligineum, widespread around the Antarctic continent, was also present but isolated at Kerguelen, possibly resulting from historical freeze–thaw cycles. The genus Polyeunoa appears to have diversified prior to colonizing the continent, leading to the co‐occurrence of at least three cryptic species around the Southern and Indian Oceans. Analyses identified that nearly all populations are presently expanding following a bottleneck event, possibly caused by habitat reduction from the last glacial episodes. Findings support multiple origins for contemporary Antarctic polynoids, and some species investigated here provide information on ancestral scenarios of (re)colonization. First, it is apparent that species collected from the Antarctic continent are endemic, as the absence of closely related species in the Kerguelen and Tierra del Fuego datasets for most lineages argues in favor of Hypothesis 1 of local origin. Next, Eunoe sp. and H. fuligineum, however, support the possibility of Kerguelen and other sub‐Antarctic islands acting as a crossroads for larvae of some species, in support of Hypothesis 3. Finally, the genus Polyeunoa, conversely, is found at depths greater than 150 m and may have a deep origin, in line with Hypothesis 2. These “non endemic” groups, nevertheless, have a distribution that is either north or south of the Antarctic Polar Front, indicating that there is still a barrier to dispersal, even in the deep sea.     

Palaeobiogeographical provenance, taphonomy, and mode of life of Aturia cubaensis (Cephalopoda, Nautiloidea) from Cainozoic deposits of Chile

The presence of Aturia cubaensis (Lea) is reported from several Cainozoic localities along the central and southern Chilean coast. The shells are very well preserved and the ultrastructure of the shell, especially of the siphuncular tube, of A. cubaensis is described and the function of the siphuncular tube discussed. A. cubaensis shows an interesting distributional pattern in Chile, becoming more frequent towards higher latitudes. It occurs in the Navidad, Ranquil, and Lacui formations of central and southern Chile and the Cameronian Stage of Tierra del Fuego, spanning a time of Eocene-Oligocene to latest Miocene, possibly even earliest Pliocene. Tierra del Fuego is the southernmost record of this species. The preservation of Aturia in all these localities is exceptionally good, no incrustation and microboring is observed in the shells. Post-mortem shell breakage is present, but usually the phramocone is not destroyed. These records contradict either the subtropical to tropical nature of the genus Aturia or existing climatic reconstructions for the southeastern Pacific during the middle to late Cainozoic. A number of southern South American names for nautiloids are synonymized with A. cubaensis: Nautilus maldonadi Philippi, Nautilus caroliameghinoi Ihering, Aturia (Sphenaturia) brueggeni Ihering, Aturia (Sphenaturia) felschi Ihering. Nautilus araucanus Philippi and Nautilus magellanicus Philippi are nomina nuda but presumably also synonyms of A. cubaensis.     

Phenotypic and genetic differentiation between diadromous and landlocked puyen Galaxias maculatus

This study reports the phenotypic and genetic differences between individuals of puyen Galaxias maculatus from two sites in the same river basin in Tierra del Fuego National Park, southern South America. Individuals from the two sampling sites presented morphometric and genetic differences. The morphometric differences indicated that individuals from Laguna Negra (LN) were short and more robust and had large eyes, whereas those from Arroyo Negro (AN) were thin and elongated and had small eyes. Genetic differences showed that AN individuals had a greater genetic structuration and an older demographic history than LN individuals. The results of this study affirmed that the individuals from the two sampling sites belong to different populations with a high degree of isolation. The demographic history could indicate that the individuals of G. maculatus which migrated to northern areas during the last glaciation settled in the Beagle Channel after its formation. The LN population could have originated after the retreat of the glaciers, migrating from AN.     

Larval development of the subantarctic squat lobster Munida subrugosa (White, 1847) (Anomura: Galatheidae), reared in the laboratory

The larval development of the squat lobster Munida subrugosa from subantarctic waters of the Beagle Channel (Tierra del Fuego, Argentina) was studied under controlled laboratory conditions of temperature, salinity, and food supply. Developmental times, survival, and growth of larvae and early juveniles were investigated. Hatching of the entire brood always occurred during one night. Larvae were kept in 100ml individual bowls with filtered seawater at 8 ± 0.5°C and fed with Artemia spp. nauplii three times a week. Larvae passed through 6 zoeal instars and one megalopa. Previously, only five zoeal instars were known from this species. Mean cumulative durations of the zoeal stages I to VI were: 20.5 ± 2.5, 33.9 ± 4.1, 43.3 ± 5.4, 52.6 ± 5, 61.2 ± 3.9, and 83days, respectively. By adding the 28days that a single megalopa took to metamorphose to crab I stage, the complete larval development lasted 111days. Highest mortality occurred prior to the moult from the zoea I to zoea II stage (79.21% ± 18.65%) and during the moult from zoea VI to megalopa (92.86%). Carapace length was 1.64 ± 0.06, 1.52 ± 0.16, 1.57 ± 0.26, 1.64 ± 0.21, 2.11 ± 0.35, and 2.58 ± 0.19mm, for zoeal stages I to VI, respectively. Carapace length of megalopae and crab I instars was similar (2.85 ± 0.28 and the 2.84 ± 0.05, respectively). Unlike other subantarctic decapods, which show a tendency towards abbreviated larval development and/or some degree of endotrophy, M. subrugosa shows an extended planktotrophic larval development synchronized with short seasonal plankton production in austral summers.     

Extra‐pair paternity in a population of Chilean Swallows breeding at 54 degrees south

Geographic patterns of variation in life‐history traits have puzzled researchers for decades. However, the widely accepted idea that mating systems exhibit a tropical–temperate latitudinal trend, with extra‐pair mating systems being the norm among temperate species and genetic monogamy the norm among tropical species, is supported by sparse data, particularly for birds breeding in the tropics and even more so for birds that breed in the southern hemisphere temperate zone. Our objective was to examine the genetic mating system of Chilean Swallows (Tachycineta meyeni) breeding at 54°S in Tierra del Fuego, Argentina. From 2006 to 2009, we examined the paternity of young in 52 broods. Contrary to predictions based on their congeners that breed at equivalent latitudes in the northern hemisphere, Chilean Swallows in our study had low rates of extra‐pair paternity (EPP), with 13.5% of nests (N = 52) having at least one extra‐pair young and 6.8% of all nestlings (N = 161) fathered by extra‐pair males. These rates are also lower than those reported for species of Tachycineta swallows that breed at tropical latitudes. We found no support for a tropical–south temperate latitudinal cline in EPP rates. The highly unpredictable weather of the island of Tierra del Fuego might be influencing parental investment at this site; small clutch sizes and low EPP rates are expected if biparental attention is crucial for chick survival and reproductive success for these aerial insectivores. We argue that the sparse sampling of mating systems in birds worldwide may have contributed to a misapprehension of a global pattern. More studies of tropical and south‐temperate systems are needed to build on theories based on a wider set of taxa.