Phylogenetic relationships of the Geoplaninae land planarians (Platyhelminthes, Tricladida) assessed with a total evidence approach, with the description of a new species of Gigantea.

Several studies have focused on the phylogenetic relationships within the Geoplaninae land planarians (Tricladida). In those studies, ancient phylogenetic relationships remained obscure. In this work, the phylogeny of Geoplaninae is assessed through three different datasets, namely morphological, molecular, and both datasets combined, i.e, a total evidence approach (TE). The data matrix consisted of six DNA regions, including a newly developed marker (DOM5), and a morphological matrix with 37 characters. The study produced the best-resolved hypothesis so far for the phylogeny of Geoplaninae, although ancient clades still remain elusive. The effect of the morphological data on the TE tree topology and clade support is seemingly negligible. The phylogenetic tree also suggests that most of the diagnostic morphological characters of the genera are homoplastic, while unambiguous unique synapomorphies can characterize some supra-generic informal groupings.

The invasive land flatworm Obama nungara (Platyhelminthes: Geoplanidae) reaches a natural environment in the oceanic island of São Miguel (Açores).

During an entomological sampling trip in the island of São Miguel (Açores, Portugal) on 02-11-2019 by José Rafael González-López, one specimen of the invasive flatworm Obama nungara Carbayo et al. 2016 was found under a rock (Fig. 1A). The specimen was photographed in situ and identified by its external morphology based on its large and broad leaf-like body with nearly parallel body margins, narrow and rounded anterior end, rounded posterior end, and dorsal pigmentation consisting of a light brown ground color covered with dark longitudinal and irregular stripes, and ventral surface grayish-white. Recent studies (Justine et al. 2020; Negrete et al. 2020) showed the reliability of photograph-based identification of O. nungara specimens. It is the sixth island where this species has been found (after Guernsey, Great Britain, Ireland, Corsica, and Madeira).

New records of the giant planarian Polycladus gayi Blanchard, 1845 (Platyhelminthes: Geoplanidae) with notes on its conservation biology.

Land planarians (Tricladida:Geoplanidae) comprise about 910 species distributed in four subfamilies and can be found on all continents except Antarctica (Sluys Riutort 2018; Sluys 2019). The Neotropical region possesses nearly 31% of all the described terrestrial planarian species, most of them belonging to the subfamily Geoplaninae (Sluys 1999; Grau Carbayo 2010). Land planarians are mostly habitat-specialists, living in the humid soils of native forest, and predating on invertebrates like earthworms, isopods, mollusks and harvestmen, among others (Ogren 1995; Carbayo Leal-Zanchet 2003; Boll Leal-Zanchet 2016). Although most planarian species seem to be physiologically sensitive, for example to environmental moisture, a few land planarian genera like Bipalium Stimpson and Obama Carbayo et al., have successfully invaded many habitats, even in highly perturbed areas (Kawaguti 1932; Sluys 2019). Therefore, some of these invertebrate species appear to be good candidates as habitat quality bioindicators according to some authors (Sluys 1998; Gerlach et al., 2013; Negrete et al., 2014).

First records of two alien land flatworms (Tricladida, Geoplanidae) from Northeastern Italy.

During a period of intense rainfall (May 2019), several specimens of land flatworms were collected from a private garden in Palazzolo dello Stella (Friuli Venezia Giulia, Udine, Italy: 45°47'40.5"N, 13°05'17.2"E). Planarians were found both in a cultivated part of the garden and in a part covered with gravel and with trees and shrubs (Pyracantha sp., Olea europaea, Pyrus communis). The animals were observed under branches, stones, tufa blocks, and pots close to a small artificial pond, but also in other parts of the garden, as well as inside buildings.

The land flatworm Amaga expatria (Geoplanidae) in Guadeloupe and Martinique: new reports and molecular characterization including complete mitogenome.

BACKGROUND: The land flatworm Amaga expatria Jones & Sterrer, 2005 (Geoplanidae) was described from two specimens collected in Bermuda in 1963 and 1988 and not recorded since. METHODS: On the basis of a citizen science project, we received observations in the field, photographs and specimens from non-professionals and local scientists in Martinique and Guadeloupe. We barcoded (COI) specimens from both islands and studied the histology of the reproductive organs of one specimen. Based on Next Generation Sequencing, we obtained the complete mitogenome of A. expatria and some information on its prey from contaminating DNA. RESULTS: We add records from 2006 to 2019 in two French islands of the Caribbean arc, Guadeloupe (six records) and Martinique (14 records), based on photographs obtained from citizen science and specimens examined. A specimen from Martinique was studied for histology of the copulatory organs and barcoded for the COI gene; its anatomy was similar to the holotype, therefore confirming species identification. The COI gene was identical for several specimens from Martinique and Guadeloupe and differed from the closest species by more than 10%; molecular characterisation of the species is thus possible by standard molecular barcoding techniques. The mitogenome is 14,962 bp in length and contains 12 protein coding genes, two rRNA genes and 22 tRNA genes; for two protein genes it was not possible to determine the start codon. The mitogenome was compared with the few available mitogenomes from geoplanids and the most similar was Obama nungara, a species from South America. An analysis of contaminating DNA in the digestive system suggests that A. expatria preys on terrestrial molluscs, and citizen science observations in the field suggest that prey include molluscs and earthworms; the species thus could be a threat to biodiversity of soil animals in the Caribbean.

First record of the invasive land flatworm Bipalium adventitium (Platyhelminthes, Geoplanidae) in Canada.

Specimens of Bipalium adventitium (Platyhelminthes, Geoplanidae) were found in Montréal, Québec, Canada. The specimens showed the typical colour pattern of the species and barcoding (Cytochrome Oxidase I) demonstrated near-identity with a sequence of the same species from the USA. This is the first record of the species in Canada.

First report of the land planarian Endeavouria septemlineata (Hyman, 1939) (Platyhelminthes, Tricladida, Continenticola, Geoplanidae) in French Polynesia.

We report the presence of the land planarian Endeavouria septemlineata from Tahiti, French Polynesia, on the basis of a single specimen collected in 2017. Identification of the species was ascertained by external and internal morphology and DNA COI sequence. The finding is of importance for conservation, since this species is a predator of soil animals.

Diversity out of simplicity: interaction behavior of land planarians with co-occurring invertebrates.

Land planarians have a simple anatomy and simple behavioral repertoire in relation to most bilaterian animals, which makes them adequate for the study of biological processes. In this study, we investigate the behavior of land planarians during interaction events with other invertebrates found in the same environment. We observed 16 different behavioral units, including seven different capture behaviors and three different prey ingestion behaviors. The capture behavior varied from very simple, such as simply covering the prey with the body, to more complex ones, including two forms of tube formation that are described for the first time. In general, the capture behaviors were similar among different predators but different for different prey. Similarly, prey ingestion type was more related to prey type than to predator species, with small soft prey being swallowed without fragmentation, large prey being crushed, and prey with a hard skeleton being perforated. Considering that land planarians face limitations due to their lack of efficient ways to retain water, thus being highly dependent on a moist environment, the set of behaviors shown by them in this study was considerably rich, especially concerning strategies to capture prey.

Preference for different prey allows the coexistence of several land planarians in areas of the Atlantic Forest.

Land planarians are recognized as important predators, yet studies on their feeding habits are usually restricted to invasive species. Thus, it is difficult to determine the real ecological role of this group in ecosystems and how their communities are structured. In the present study, we analyzed the diet of six co-occurring Neotropical land planarians and their success in capturing prey, based on experiments in the laboratory, in order to determine how they share resources in the same environment. We also calculated indices of food niche breadth and food niche overlap for land planarians for the first time. The diet of Luteostriata abundans comprises only woodlice and the diets of Obama ficki and Obama ladislavii are composed only of gastropods, while Paraba multicolor and Obama anthropophila feed on both gastropods and other land planarians. An invasive species recently found in Western Europe, Obama nungara, showed the highest food niche breadth, feeding on gastropods, earthworms and planarians. We found the highest niche overlap between O. anthropophila and P. multicolor. The results suggest that land planarians are frequent predators of woodlice and land gastropods in the Neotropical ecozone and thus are important for the maintenance of native ecosystems and for the control of invasive species. The coexistence of several species in the same habitat is possible due to the use of different species as main prey, which reduces interspecific competition.

Micro-computed tomography scan and virtual histological slide data for the land planarian Obama otavioi (Platyhelminthes).

BACKGROUND: We investigated whether images obtained through X-ray micro-computed tomography (µCT) can be used in conjunction with traditional methods for morphological studies of soft-bodied land planarians. µCT is non-invasive and provides true-to-scale three-dimensional imagery at high resolution. We compared µCT-based images of a recently described land planarian species of Obama otavioi (Platyhelminthes) with those obtained from light microphotography of histological sections, most of which were also digitized at high magnification. FINDINGS: The specimens studied were collected in 2012. Subsequent µCT-based images of the stained body of a paratype show nearly all morphological features provided by traditional histology, with the exception of particularly minute structures, smaller than 5 µm, such as the sensory pits and single muscle fibers, which are best visible on traditional histological sections. Because the technique is non-destructive, the scanned specimen is preserved without damage. The raw and derivative µCT data and virtual histological sections are freely available in GigaDB. CONCLUSIONS: The µCT datasets of these stained soft-bodied organisms reveal images of external and internal structures that support previous taxonomic studies. This technique can be particularly important for non-destructively revealing internal details of whole museum specimens at a faster rate than histology alone. High-resolution virtual histological slides also allow further searches for new, previously unstudied morphological features. The use of X-ray equipment with higher resolution can enable smaller sensory organ and muscle fiber details to be seen. The image sets, µCT-based images and digitized histological slides can be disseminated without the constraints of specimen loans.

A taste for exotic food: Neotropical land planarians feeding on an invasive flatworm.

Invasive species establish successfully in new habitats especially due to their ability to include new species in their diet and due to the freedom from natural enemies. However, native species may also adapt to the use of new elements in their ecosystem. The planarian Endeavouria septemlineata, first recorded in Hawaii, was later found in Brazil. Recently, we found it in human-disturbed areas in southern Brazil and here we investigate its interactions with other invertebrates both in the field and in the laboratory. We observed the species in the field during collecting activities and hence maintained some specimens alive in small terraria in the laboratory, where we offered different invertebrate species as potential prey and also put them in contact with native land planarians in order to examine their interaction. Both in the field and in the laboratory, E. septemlineata showed a gregarious behavior and was found feeding on woodlice, millipedes, earwigs and gastropods. In the laboratory, specimens often did not attack live prey, but immediately approached dead specimens, indicating a scavenging behavior. In an experiment using the slug Deroceras laeve and the woodlouse Atlantoscia floridana, there was a higher consumption of dead specimens of woodlice and slugs compared to live specimens, as well as a higher consumption of dead woodlice over dead slugs. Four native land planarians of the genus Obama and one of the genus Paraba attacked and consumed E. septemlineata, which, after the beginning of the attack, tried to escape by tumbling or using autotomy. As a scavenger, E. septemlineata would have no impact on the populations of species used as food, but could possibly exclude native scavengers by competition. On the other hand, its consumption by native land planarians may control its spread and thus reduce its impact on the ecosystem.