J. F. A. Sprent

Ascaridoid nematodes of amphibians and reptiles: Dujardinascaris

From the known species occurring in crocodilians, the genus Dujardinascaris is redefined and found to be a homogenous group of species, with dujardini Travassos, 1920 as the type species. The following new species are described and added to the genus: gedoelsti, puylaerti, waltoni, mawsonae and taylorae. The following species are excluded from the genus: vandenbrandeni, australiensis, tasmani, alata and antipini. The distribution of the species in Dujardinascaris is as follows: in African crocodiles—dujardini, madagascariensis, gedoelsti, and puylaerti; in South American caimans—longispicula, paulista, and chabaudi (possibly a synonym of paulista); in North American alligator—waltoni; in Crocodylus acutus—helicina; in the Indian gavial—woodlandi; in crocodiles in Papua New Guinea and Australia—mawsonae and taylorae. These species are differentiated mainly by the relative length of the spicules and the form of the gubernaculums in the males and by the relative length of the vagina and the form of the vulva in the females.

Ascaridoid nematodes of amphibians and reptiles: Gedoelstascaris n.g. and Ortleppascaris n.g.

Two new genera, Gedoelstascaris and Orleppascaris, are proposed for species of ascaridoid nematodes occurring in crocodilians and previously included in Dujardinascaris. Species included in Gedoelstascaris are vandenbrandeni Baylis, 1929 as type species and australiensis Baylis, 1931 (= salomonis Kreis, 1940). These species occur in Crocodylus spp. in Africa and Australia respectively and are characterised by lips with a rostral plate, without interlocking processes or dentigerous ridges, with well-developed interlabia, lobulated ventriculus, and excetory pore in front of the nerve ring. Species included in Ortleppascaris are: nigra Gedoelst, 1916 (= tasmani Ortlepp, 1932) as type species; alata Baylis, 1947: antipini Mozgovoy, 1950. These species occur in Crocodylus, Caiman and Alligator and are characterized by flat lips with alate margins, without anterior rostral plate, interlocking processes or dentigerous ridges, with weakly developed interlabia, by an irregular-shaped ventriculus, excretory pore behind or between the subventral lips, and by the presence of lateral alae or cuticular thickenings in the oesophageal region. The significance of this proposal is discussed in relation to the radiation and dispersal of ascaridoids of crocodilians.

Ascaridoid nematodes of amphibians and reptiles: Multicaecum and Brevimulticaecum

The genus Multicaecum Baylis 1923, sensu Hartwich 1957, was found to be heterogeneous, comprising species which are released to two distinct genera, namely Multicaecum Bavlis, 1923 and Brevimulticaecum. The latter name is derived from the subgenus Brevinulticaecum Mozgovoy, in Skrjabin, Shikhobalova, and Mozgovoy, 1951 by raising it to generic rank and emending the definition. Multicaecum contains a single species, agile Wedl, 1861 occurring in Crocodylus spp. in Africa, India and Australia, and is characterized by smooth rounded lips, each with a dentigerous ridge comprising small sharp denticles. The excretory pore is level with the nerve ring or behind it, and the ventricular appendices are long and slender. The species gangeticum Maplestone 1930 and quadrata Linstow 1904 are excluded from Multicaecum and regarded as species inquirendae incertae sedis. Brevimulticaecum contains five species occurring in the caimans and the alligator of the New World: baylisi Travassors, 1933 (type species; acuticauda Schuurmans-Stekhoven, 1937 is placed in synonomy under baylisi); stekhoveni Baylis, 1947; tenuicolle Rudolphi, 1819; and two new species. Brevimulticaecum spp. are characterized by flat lips with alate margins and notches, without dentigerous ridges, excretory pore in front of or at nerve ring and the ventriculus with short appendices. The significance of this proposal is discussed in relation to the other genera of ascaridoid nematodes in crocodilians.

Ascaridoid nematodes of amphibians and reptiles: Polydelphis, Travassosascaris n.g. and Hexametra

The ascaridoid nematodes with more than two uterine branches, which occur in snakes and lizards, are grouped into three genera: (1) Polydelphis (without interlabia, with four uterine branches) containing the type species, p. anoura, occurring in Old World pythons, with p. brachycheilos as a species dubium. (2) Travassosascaris, a new genus with interlabia and with four uterine branches, with type species T. araujoi (new name for p. quadrangularis (Schneider) of Araujo, 1969) occurring in New World rattlesnakes. (3) Hexametra (without interlabia, with six uterine branches) containing species in lizards and snakes. In lizards, H. hexametra (type species), H. applanata, H. angusticaecoides and H. rotundicaudata are tentatively differentiated. In snakes, two Hexametra species are tentatively differentiated: (1) H. boddaertii (with three synonyms) in New World pit vipers and colubrids; (2) H. quadricornis (with twenty-two synonyms) in Old World viperids, elapids and colubrids. The morphology, host range, geographical distribution, development and harmful effects of these species are discussed.

Ascaridoid nematodes of amphibians and reptiles: Sulcascaris

The genus Sulcascaris is upheld and redefined. Sulcascaris sulcata from Chelonia mydas and Caretta caretta is redescribed, from Rudolphis type material and material from the Mediterranean and Western Pacific, demonstrating that the excretory pore opens between the subventral lips and that the excretory cell is bilateral, comprising a short filamentar right component and a more capacious ribbon-like left component containing the nucleus. The phylogenetic significance of this form of excretory system occurring in an ascaridoid of a marine reptile is discussed. It is concluded from comparative studies, based on measurements, sections and electron scanning micrographs, that fourth stage larvae of S. sulcata collected from the stomach of turtles are identical with fourth stage ascaridoid larvae found in the adductor muscle of scallops (Amusium balloti and Chlamys sp.) and that turtles become infected with this species by eating bivalves. Adult S. sulcata were obtained from tank-reared C. caretta fed with encapsulated larvae from scallops.

Ascaridoid nematodes of amphibians and reptiles: Terranova

Three species in the genus Terranova occurring in reptiles are redescribed and differentiated: (1) Terranova lanceolata (Molin 1860) new combination, [=Terranova braziliensis (Schuurmans-Stekhoven, 1937) Hartwich, 1957] from Melanosuchus niger in Brazil; (2) Terranova crocodili (Taylor 1924) from crocodiles in West Africa and Malaya and from Crocodylusporosus and C. johnstoni in Australia; (3) Terranova caballeroi Barus and Coy Otero, 1966 from colubrine snakes in Louisiana and Florida, U.S.A. and Cuba. The distribution and affinities of these species is discussed. Ascaris quadrata Linstow, 1904 is regarded as a species dubium incertae sedis.

Ascaridoid nematodes of Sirenians--the Heterocheilinae redefined

The two ascaridoids of sirenians, Heterocheilus tunicatus Diesing, 1839, and Paradujardinia halicoris (Owen, 1833), are redescribed. A basic affinity between the two species is indicated in the bilateral structure of the excretory system, the globular ventriculus, long intestinal caecum, and the form of the male tail. The subfamily Heterocheilinae is redefined so as to contain these two genera. It is proposed that the subfamily comprises a natural suprageneric group within the Ascarididae sensu Hartwich, 1974 containing, in addition to Heterocheilus and Paradujardinia, the following genera occurring in freshwater, estuarine and coastal vertebrates: Multicaecum Baylis, 1923; Dujardinascaris Baylis, 1947; Gedoelstascaris Sprent, 1978; Ortleppascaris Sprent, 1978; Brevimulticaecum Mozgovoy sensu Sprent, 1979; Krefftascaris Sprent, 1980. The suggestion is made that the ascaridoids of sirenians originated from forms in fluviatile lower vertebrates.

Ascaridoid Nématodes of South American mammals, with a definition of a new genus

Ascaridoid nematodes occurring in South American mammals are divided into categories based on their possible origin. The affinities are discussed of five species so far known only from the Neotropical Region. Toxocara alienata (Rudolphi 1819) is reported from Nasua rufa socialis, Procyon cancrivorus, and Tayassus torquatus. The specimens from T. torquatus are described and found most closely to resemble Toxocara mackerrasae from south-east Asian and Austrialian rodents. Anisakis insignis from Inia geoffrensis is transferred back to Peritrachelius Diesing, 1851, on account of the structure of the lips and spicules. P. insignis is shown to exhibit remarkable convergence of lip structure with Lagochilascaris turgida from Didelphis marsupialis. Galeiceps longispiculum (Freitas & Lent, 1941) from Pteronura brasiliensis is confirmed as a species distinct from G. cucullus (Linstow, 1899) and G. spinicollis (Baylis, 1923), but G. simiae (Mosgovoy, 1951) is considered to be a synonym of G. spinicollis. An error in the host record of G. spinicollis is corrected from Cercopithecus leucampyx kandti to Lutra maculicollis kivuana. Ascaris dasypodina Baylis, 1922 from armadillos, including Cabassous unicinctus and Tolypeutes matacos, is redescribed and placed in a new genus Bairdascaris. The question is raised as to whether some species in Lagochilascaris, Galeiceps, and Toxocara may have crossed directly by sea from Africa to South America, rather than entering via North America.

Ascaridoid nematodes of amphibians and reptiles: Angusticaecum and Krefftascaris n.g.

Ascaridoid nematodes reported from terrestrial and freshwater chelonians are described under two monotypic genera, Angusticaecum and a new genus Krefftascaris respectively. The former genus contains A. holopterum (Rudolphi, 1819) Baylis, 1920 [synonym A. brevispiculum Chapin, 1924], reported in the natural state from testudinid and emydid tortoises in Europe, U.S.S.R., Iran, Brazil and North Africa. The latter genus contains a new species, K. parmenteri, reported from chelid freshwater turtles in Eastern Australia. It is concluded that the former is most closely related to species in other genera in terrestrial reptiles, whereas the latter is closest to Gedoelstascaris spp. in crocodilians. Host-parasite relationships over evolutionary time between ascaridoids and chelonians are discussed.

Ascaridoid nematodes of amphibians and reptiles: Typhlophorus, Hartwichia and Trispiculascaris

Four little-known ascaridoid species occurring in crocodilians are discussed. Typhlophorus lamellaris Linstow, 1906 and Hartwichia rousseloti Chabaud & Bain, 1966 are considered to be closely related to Heterocheilus tunicatus Diesing, 1839; Porrocaecum assymmetricum Ortlepp, 1932 is transferred to Trispiculascaris together with T. trispiculascaris Skrjabin, 1916. These three genera are placed in the subfamily Heterocheilinae sensu Sprent (1980) on account of the structure of the oesophago-intestinal junction, the labial pulp and, where known, the male tail. A key to eight genera of Heterocheilinae in crocodilians is provided.