A new species of Caryospora Léger, 1904 (Apicomplexa: Eimeriidae) from the endangered Round Island boa Casarea dussumieri (Schlegel) (Serpentes: Bolyeridae) of Round Island, Mauritius: an endangered parasite?

Biodiversity of the Coccidia (Apicomplexa: Conoidasida) in vertebrates: what we know, what we do not know, and what needs to be done

Over the last two decades my colleagues and I have assembled the literature on a good percentage of most of the coccidians (Conoidasida) known, to date, to parasitise: Amphibia, four major lineages of Reptilia (Amphisbaenia, Chelonia, Crocodylia, Serpentes), and seven major orders in the Mammalia (Carnivora, Chiroptera, Lagomorpha, Insectivora, Marsupialia, Primates, Scandentia). These vertebrates, combined, comprise about 15,225 species; only about 899 (5.8%) of them have been surveyed for coccidia and 1,946 apicomplexan valid species names or other forms are recorded in the literature. Based on these compilations and other factors, I extrapolated that there yet may be an additional 31,381 new apicomplexans still to be discovered in just these 12 vertebrate groups. Extending the concept to all of the other extant vertebrates on Earth; i.e. lizards (6,300 spp.), rodents plus 12 minor orders of mammals (3,180 spp.), birds (10,000 spp.), and fishes (33,000 spp.) and, conservatively assuming only two unique apicomplexan species per each vertebrate host species, I extrapolate and extend my prediction that we may eventually find 135,000 new apicomplexans that still need discovery and to be described in and from those vertebrates that have not yet been examined for them! Even doubling that number is a significant underestimation in my opinion.

A new coccidian parasite of the boodie, Bettongia lesueur (Mammalia: Marsupialia: Potoroidae), from Australia

Four of 28 wild boodies or burrowing bettongs, Bettongia lesueur (Quoy et Gaimard) passed oocysts of species of Eimeria Schneider, 1875. The boodies are surviving on off-shore islands and in large predator-proof sanctuaries on the mainland where they were reintroduced. The boodie is a potoroid marsupial extinct from the mainland of Australia due to predation from red foxes and feral cats. Comparison with other species of the genus Eimeria indicates that the coccidium found represents a new species. Sporulated oocyst of Eimeria burdi sp. n. are pyriform, 21.0-24.0 µm (mean 22.6 µm) by 14.0-16.0 µm (14.9 µm), with a length/width ratio 1.31-1.71 (1.52) and 1-µm-thick yellowish bilayered wall. Micropyle is present at the thinner apex end filled with hyaline body. Polar granules are absent. Sporocysts are ellipsoidal, 10.0-13.5 µm (11.8 µm) by 7.0-8.5 µm (7.4 µm), shape index is 1.42-1.89 (1.63) and a very thin, poorly defined unilayered sporocyst wall is 0.2 µm thick with a domelike almost indistinct Stieda body. Substieda body is indistinct.

Coextinction and Persistence of Dependent Species in a Changing World

The extinction of a single species is rarely an isolated event. Instead, dependent parasites, commensals, and mutualist partners (affiliates) face the risk of coextinction as their hosts or partners decline and fail. Species interactions in ecological networks can transmit the effects of primary extinctions within and between trophic levels, causing secondary extinctions and extinction cascades. Documenting coextinctions is complicated by ignorance of host specificity, limitations of historical collections, incomplete systematics of affiliate taxa, and lack of experimental studies. Host shifts may reduce the rate of coextinctions, but they are poorly understood. In the absence of better empirical records of coextinctions, statistical models estimate the rates of past and future coextinctions, and based on primary extinctions and interactions among species, network models explore extinction cascades. Models predict and historical evidence reveals that the threat of coextinction is influenced by both host and affiliate traits and is exacerbated by other threats, including habitat loss, climate change, and invasive species.

A new species of Caryospora (Apicomplexa: Eimeriidae) from the flathead snake, Tantilla gracilis (Ophidia: Colubridae), in southeastern Oklahoma

A single flathead snake, Tantilla gracilis , collected in early October 2010 from Choctaw County, Oklahoma, was found to harbor an undescribed species of Caryospora . Oocysts of Caryospora choctawensis n. sp. were spherical to subspherical, 15.8 × 15.0 (14-18 × 14-16) µm, with a thick, bilayered wall and a shape index (length∶width) of 1.1. A micropyle and an oocyst residuum were absent, but prominent Stieda and bubble-like sub-Stieda bodies were present as well as a bilobed polar granule near the oocyst wall. Sporocysts were ovoidal, 10.8 × 9.0 (10-12 × 8-9) µm, with a shape index of 1.2. The sporocyst residuum was spherical and composed of a cluster of granules often membrane-bound. This is the second time a caryosporan species has been reported from T. gracilis but the first coccidian ever described from a reptilian host in Oklahoma. Additional T. gracilis from Arkansas (n  =  6), Oklahoma (n  =  1), and Texas (n  =  7) were examined, and a single specimen from Newton County, Arkansas harbored Caryospora gracilis Upton, McAllister, Trauth, and Bibb, 1992 , previously reported from T. gracilis collected in Arkansas and Texas.