Louis Du Preez | North-West University (original) (raw)

Papers by Louis Du Preez

The global fungal disease chytridiomycosis can have catastrophic effects on amphibian populations... more The global fungal disease chytridiomycosis can have catastrophic effects on amphibian populations leading to declines and even extinctions. Madagascar with its highly endemic and diverse amphibians is particularly vulnerable to emerging infectious diseases. In this study we report on a histological survey of chytridiomycosis at multiple localities in eastern Madagascar. The amphibian chytrid fungus was not detected in 527 frogs that altogether were examined. A more comprehensive survey involving all biogeographic zones on the island is urgently needed before a conclusion can be made about the chytridiomycosis classification of Madagascar. Suggestions on future research aimed at managing the disease are also made.

Emerging Infectious Diseases, 2004

African Zoology, Oct 1, 2011

Morphological similarities between the tadpoles of Amietia umbraculata and A. vertebralis have le... more Morphological similarities between the tadpoles of Amietia umbraculata and A. vertebralis have led to confusion and incorrect descriptions and identifications in the literature. Based on 33 body measurements and ratios we revised the morphological descriptions of the tadpoles of the two species. Tadpole identification was verified through DNA sequencing using mitochondrial (16S) gene fragments. A combination of four morphological characters proved to be informative and consistent in distinguishing between tadpoles of the two species. Tadpoles of A. umbraculata are characterized by having four labial tooth rows in the lower jaw, extensive tail mottling, a dorsal fin that originates well behind the body, reaching a maximum depth at 50% of the tail length, and an average tail length of 1.9 times body length. Amietia vertebralis tadpoles on the other hand are characterized by having five or more labial tooth rows in the lower jaw, tail mottling that is confined to the upper half of the tail musculature, a dorsal fin that originates at the body-tail junction but retains a low profile, rising abruptly to reach a maximum depth at about 40% of the tail length, and an average tail length of 1.5 times body length. These four characters identify the two species without ambiguity.

Chemical Communications (London), 1968

REFERENCE ALIGNMENT. 12S rRNA sequences (fasta format) for Pelomedusa species

Parasitology Research, 2020

Polystomes (Monogenea: Polystomatidae) of freshwater turtles are currently represented by five ge... more Polystomes (Monogenea: Polystomatidae) of freshwater turtles are currently represented by five genera, namely Neopolystoma, Polystomoides, Polystomoidella, Uropolystomoides and Uteropolystomoides. These parasites can infect the urinary, oral and/or the conjunctival sac systems of their hosts, showing strict site specificity. A recent phylogenetic study showed that the two most diverse genera within chelonian polystomes, i.e. Neopolystoma and Polystomoides, are not monophyletic. Furthermore, polystomes infecting the conjunctival sacs of their host, except for one species, formed a robust lineage. A fusiform egg shape has been reported for conjunctival sac polystomes and it was assumed that this characteristic could be a good character for the systematics of polystomes. Our objective in the present work was, therefore, to study more in depth the morphology of polystomes collected from the conjunctival sacs of chelonians to find characters defining a putative new genus. To achieve this objective, more specimens were collected in 2018 and 2019 from turtles sampled in North Carolina and Florida (USA) to extend taxon sampling for the phylogenetic analysis. Morphological characters of relevant polystome specimens were re-examined from several collections from Asia, Australia, Europe, South Africa, South America and North America. Based on a Bayesian tree inferred from the analysis of four concatenated genes, namely 12S, 18S, 28S and COI, polystomes found in the conjunctival sacs were grouped in three distinct lineages, the first one including a single species infecting an Australian pleurodire turtle; the second one including eleven species infecting cryptodire turtles of South America, North America and Asia; and the last one including a single species infecting a softshell cryptodire turtle of North America. Based on observations of live specimens by Dr. Sylvie Pichelin and our morphological analysis, the conjunctival sac polystomes from Australian turtles are small, cannot extend their body significantly, have a spherical ovary and egg, have a large genital bulb and possess latero-ventral vaginae at the level of the testis. Based on observations of live specimens and morphological analysis of whole mounted specimens, polystomes of the second lineage share the following morphological characteristics: the ability to stretch out and double their length, a long oval ovary, a separate egg-cell-maturation-chamber, fusiform to diamond-shaped eggs with acute tips, small genital bulb and vaginae peripheral on the side of the body at the level of the testis. The polystome species of the third lineage occupies a basal position, has the ability to stretch out and possess an elongated ovary, a large fusiform egg with rounded tips, a small genital bulb and small latero-ventral vaginae at the level of the ovary. These three distinct conjunctival sac polystome lineages are herein described as separate new genera, Aussietrema, Fornixtrema and Apaloneotrema, respectively.

African Zoology, 2020

This communication details the maternal care of Hemisus marmoratus and Hemisus guttatus. A Hemisu... more This communication details the maternal care of Hemisus marmoratus and Hemisus guttatus. A Hemisus mother stays with the eggs, protecting them during their time in the nest chamber, and ensures their ultimate arrival in a body of water, at varying stages of development, via a variety of different techniques, ranging from nest placement and slide construction to tadpole transportation. We confirm that a sticky glue-like substance is used during inguinal amplexus of H. guttatus, with only the hands of the male being glued to the female. Field observations indicate that H. marmoratus females carry their offspring to the water, gluing her hind legs together to increase the surface area for the tadpoles to adhere to during the journey.

Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie, 2012

Frogs change their call pitch to adapt to the traffic noise in urbanenvironments. Male frogs call... more Frogs change their call pitch to adapt to the traffic noise in urbanenvironments. Male frogs calls to attract females or to defend territories from rival males.Females of some species prefer lower-pitched calls which indicate larger, more experiencedmales. Acoustic interference occurs when the background noise reduces the active distance.

Systematic Parasitology, 2020

Polystoma chaochiaoensis from the urinary bladder of the chaochiao frog Rana chaochiaoensis Liu w... more Polystoma chaochiaoensis from the urinary bladder of the chaochiao frog Rana chaochiaoensis Liu was briefly described in a symposium abstract and presented at the Third Symposium on Parasitology of China in 1990. Types were not assigned and the original specimens collected are no longer available. The morphological description was incomplete and no illustrations were provided. We consider Polystoma chaochiaoensis a nomen nudum and provide a full description for the species and assign types. Based on morphological characteristics and molecular data of partial 18S rDNA sequences, we describe this species as Polystoma luohetong n. sp. Out of 578 frogs examined, 16 male and 38 female frogs were infected (prevalence 9.3%; mean intensity 1.02). Polystoma luohetong n. sp. is distinguished from all other Polystoma species by the presense of a prominent crest on the hamulus as well as by the shape and size of marginal hooklets and the intestinal arrangement. Furthermore, the phylogentic analysis based on the 18S rRNA gene shows Polystoma luohetong n. sp. well nested within the Ploystoma clade and as a sister taxon to Polystoma integerrimum.

FIGURE5. Phylogenetic tree of two species of Serpinema cayennensis n. sp. and four species of Cam... more FIGURE5. Phylogenetic tree of two species of Serpinema cayennensis n. sp. and four species of Camallanus based on Bayesian Inference analysis of partial cytochrome oxidase subunit I (COI) sequences.

FIGURE 1. Maximum Likelihood tree for helmeted terrapins (Pelomedusa spp.) using 1848 bp of mitoc... more FIGURE 1. Maximum Likelihood tree for helmeted terrapins (Pelomedusa spp.) using 1848 bp of mitochondrial DNA (12S, cyt b, ND4+tRNAs), rooted with Pelusios sinuatus. Terminal clades collapsed to cartoons. The topology of the Bayesian 50% majority rule consensus tree was identical. Numbers along branches indicate bootstrap support and clade support under BI (posterior probabilities) greater than 50 or 0.95, respectively. Asterisks represent maximum support under both methods. Colours and symbol correspond to the map (Fig. 2). On the right, proposed species names indicated; in brackets, mtDNA lineages. For clade membership of individual samples, see Table S1. The questionable sample MTD T 5484 from Swellendam District (Western Cape), South Africa, is highlighted in red (see text). The shown terrapins are Pelomedusa neumanni (top; Kakamega, Kenya) and P. galeata (bottom; Port Elizabeth, South Africa—photos: H. Prokop and W.R. Branch).

Pelomedusa galeata (Schoepff, 1792) 1792 Testudo galeata Sc... more Pelomedusa galeata (Schoepff, 1792) 1792 Testudo galeata Schoepff —Restricted type locality (Hewitt 1935): environs of Cape Town, South Africa; lectotype (Fritz et al. 2014): Biological Museum of Lund University, ZMUL 6481 (Fig. 3 bottom in Fritz et al. 2014) 1835 Pentonyx capensis Duméril & Bibron —Restricted type locality (by lectotype designation, Fritz et al. 2014): Cape of Good Hope, South Africa; lectotype (Fritz et al. 2014): Muséum National d'Histoire naturelle, Paris, MNHN 9506 (Fig. 4 in Fritz et al. 2014) 1863 Pelomedusa nigra Gray —Type locality: Natal, South Africa; lectotype (Fritz et al. 2014): The Natural History Museum, London, BMNH 1849.1.30.27 (Fig. 6 top in Fritz et al. 2014) 1935 Pelomedusa galeata devilliersi Hewitt —Type locality: Besondermeid, Steinkopf, Northern Cape, South Africa; holotype: Port Elizabeth Museum, PEM R 14962 (Fig. 7 bottom in Fritz et al. 2014) 1935 Pelomedusa galeata orangensis Hewitt —Type locality: Kimberley neighbourhood (?), Northern Cape, South Africa; holotype: McGregor Museum, Kimberley, lost (Fig. 4 of Plate XXXII in Hewitt 1935) Diagnosis: Large-sized, often dark-coloured helmeted terrapins with an exceptional maximum straight carapacial length of 32.5 cm (Hewitt 1935, discussed in Branch et al. 1990). However, the normal shell length of adult terrapins is around 26 cm. Pectoral scutes always with broad or very broad contact at plastral midseam. In approximately 50% of all terrapins two small temporal scales present on each side of head, the others having one large undivided temporal scale. Two small barbels below chin. Soft parts dorsally darker than ventrally. Carapace and plastron of adults often mainly or entirely dark. However, in the western and northwestern parts of the range adults may be light-coloured with mainly or entirely yellow plastra. Pelomedusa galeata differs from all other Pelomedusa species except P. subrufa</i [...]

Pelomedusa candidate species A This candidate species from Cameroon correspond... more Pelomedusa candidate species A This candidate species from Cameroon corresponds to mtDNA lineage I of Vargas-Ramírez et al. (2010). It is genetically clearly distinct and differs in 12S and cyt b sequences by uncorrected p distances resembling the divergences among other Pelomedusa species (Tables 1 and 3). Since there is just one genetically verified voucher specimen available (Zoologisches Forschungsmuseum Alexander Koenig, Bonn, ZFMK 15171, Mokolo, Margui- Wandala, Extreme North Province, Cameroon, coll. Wolfgang Böhme, 14–17 February 1974), we refrain from describing this species formally. ZFMK 15171 is a dark-coloured subadult terrapin of 9.3 cm straight carapacial length, resembling in gross morphology P. schweinfurthi or dark-coloured P. variabilis. However, unlike P. schweinfurthi, the pectoral scutes of ZFMK 15171 are triangular and do not reach the plastral midseam. Another terrapin from the same source region was only sampled, but not collected (Museum of Zoology, Senckenberg Dresden, Tissue Collection, MTD T 5183, Maroua, Extreme North Province, Cameroon) and is genetically very similar. Our phylogenetic analyses of mtDNA sequences place candidate species A in the well-supported northern clade of Pelomedusa (Fig. 1). Therein, it is best understood as having a basal position. Pelomedusa candidate species A differs from all other Pelomedusa species by the presence of guanine (G) instead of cytosine (C) at position 212, by the presence of thymine (T) instead of cytosine (C) at position 222, by the presence of cytosine (C) instead of thymine (T) or adenine (A) at position 302, by the presence of cytosine (C) instead of adenine (A) or guanine (G) at position 325, by the presence of thymine (T) instead of adenine (A) or guanine (G) at position 343, and by the presence of adenine (A) instead of cytosine (C) or thymine (T) at position 345 of the 360-bp-long reference alignment of the 12S rRNA gene (Supporting Information). In additio [...]

Questionnaire used for folk taxonomy investigations in Zululand. Interview template used for the ... more Questionnaire used for folk taxonomy investigations in Zululand. Interview template used for the semi-structured questionnaire in this study. (DOCX 18Â kb)

Du, Louis H., Verneau, Olivier, Gross, Timothy S. (2007): Polystoma floridana n. sp. (Monogenea: ... more Du, Louis H., Verneau, Olivier, Gross, Timothy S. (2007): Polystoma floridana n. sp. (Monogenea: Polystomatidae) a parasite in the green tree frog, Hyla cinerea (Schneider), of North America. Zootaxa 1663: 33-45, DOI: 10.5281/zenodo.179988

FIGURE3. Phylogenetic tree of two species of Serpinema and seven species of Camallanus based on B... more FIGURE3. Phylogenetic tree of two species of Serpinema and seven species of Camallanus based on Bayesian Inference analysis of partial 28S rDNA sequences.

FIGURE2. Serpinema cayennensis n. sp. from Rhinoclemmys punctularia Daudin from French Guiana, ph... more FIGURE2. Serpinema cayennensis n. sp. from Rhinoclemmys punctularia Daudin from French Guiana, photomicrographs. A—anterior end of body, male, lateral view; B—anterior end of body, female, lateral view; C—buccal capsule, male, lateral view; D—buccal capsule, female, lateral view; E—dorsal trident, female, dorsal view; F—part of female genital system near vulva, lateral view; G—posterior end of body, female, lateral view; H—posterior end of body, male, lateral view; I—male spicules, lateral view.

Parasite host-switching from the invasive American red-eared slider, Trachemys scripta elegans, t... more Parasite host-switching from the invasive American red-eared slider, Trachemys scripta elegans, to the native Mediterranean pond turtle, Mauremys leprosa, in natural environments