Growth and the expression of alternative life cycles in the salamander Ambystoma talpoideum (Caudata: Ambystomatidae)

Complex life cycles (CLCs) contain larval and adult phases that are morphologically and ecologically distinct. Simple life cycles (SLCs) have evolved from CLCs repeatedly in a wide variety of lineages but the processes that may underlie the transition have rarely been identified or investigated experimentally. We examined the influence of larval growth rate on the facultative expression of alternative life cycles (metamorphosis or maturation as gill-bearing adults [= paedomorphosis]) in the salamander Ambystoma talpoideum. We manipulated growth rates by altering the amount of food individuals received throughout larval development. The expression of alternative life cycles in A. talpoideum is influenced by growth via food levels, but the same growth rates at different points in the larval period elicit different responses. Individuals were more likely to metamorphose (i.e. express a CLC) when food levels and growth rates were high later in development and more likely to mature without metamorphosing (SLC) when growth rates were comparatively low during the same point in development. Growth rates at particular points in development, rather than overall larval growth rate, may be an important proximate factor in salamander life-cycle evolution.  © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 80 , 639–646.     

Three New Species of Eimeria (Apicomplexa: Eimeriidae) from Nerodia rhombifem (Serpentes: Colubridae) from Texas1

Three new species of Eimeria (Apicomplexa: Eimeriidae) are described from the intestinal contents of Nerodia rhombifera (Serpentes: Colubridae) from Texas. Oocysts of Eimeria infirmus are irregular in shape, 11.6 (8.8–14.4) μm in diameter, with a smooth, thin wall that ruptures easily, releasing free sporocysts. A small polar granule is usually present, but a micropyle and oocyst residuum are absent. Sporocysts are bean-shaped with one side flattened slightly, 9.1 times 5.0 (7.2–10.4 times 4.4–5.8) μm, with what may be a Stieda body consisting of a slight thickening of one end of the sporocyst. Each sporocyst contains a spherical or ellipsoid residuum and sporozoites, each with a single, posterior refractile body. Oocysts of Eimeria rhombifera are spherical or subspherical, 13.1 times 12.6 (12.0–14.4 times 11.2–14.4) μm, with a smooth, frail wall. A polar granule is present, but a micropyle and oocyst residuum are absent. Sporocysts are ovoid, 8.8 times 5.5 (8.0–9.6 times 5.0–6.0) μm, each with a Stieda body. Each sporocyst contains a spherical or subspherical residuum and sporozoites, each with a single posterior refractile body. Oocysts of Eimeria tenuis are ellipsoidal in shape, 17.2 times 10.8 (15.2–20.8 times 9.6–12.0) μm, with a smooth, thin wall. A polar granule and oocyst residuum are present, but a micropyle is absent. Sporocysts are elongate, 13.2 times 4.9(11.2–15.2 times 4.4–5.6) μm, each with a Stieda body consisting of a thickening of the sporocyst wall. Each sporocyst contains a spherical or subspherical residuum and sporozoites with anterior and posterior refractile bodies.     

Infracommunity of parasite helminths of Ambystoma lernaensis (Caudata: Ambystomatidae) in Lerma,Mexico

The helminth infracommunity structure was analyzed in 48 salamanders (Ambystoma lermaensis) from San Pedro Tlaltizapán, Lerma, Estado de Mexico (June 1997 to March 1999). Richness (2.46 +/- 1.8), abundance (29.5 +/- 42.3), and diversity (0.64 +/- 0.58) levels characterize these communities as depauperate, similar to other amphibian helminth communities worldwide. Apparently, the main forces determining infracommunity structure are ectothermy (as regulator of the ingestion rate), and the opportunistic feeding habits of the hosts, because 80% of the helminth taxa enter the host by ingestion of intermediate hosts.     

Five new species of Eimeria (Apicomplexa: Eimeriidae) from lizards

Five new species of Eimeria are described from lizards. Eimeria baltrocki n. sp. was found in the berber skink, Eumeces schneideri, from Egypt. The oöcysts are cylindroidal, averaging 38 × 18.3 m, with a single thick oöcyst wall. Most oöcysts possess a single polar granule; a micropyle and oöcyst residuum are absent. The sporocysts are ellipsoidal and average 11.5 × 8.1 m, each with a large, globular sporocyst residuum; the Stieda body is absent. Eimeria anolidis n. sp. is described form the common anole, Anolis carolinensis, from Florida, USA. The oöcysts are cylindroidal and average 31 × 15.8 m with a thick, single-layered oöcyst wall. Two polar granules are usually present; a micropyle and oöcyst residuum absent. The sporocysts are ellipsoidal and average 9.4 × 7.5 m with a globular sporocyst residuum; the Stieda body is absent. Eimeria guyanensis n. sp is recorded in the ameiva, Ameiva ameiva, from Guyana, South America. The oöcysts are spherical to subspherical, average 19.0 × 17.8 m and possess a thick, single-layered oöcyst wall. Numerous polar granules are present (n > 5); a micropyle and oöcyst residuum are absent. The sporocysts are spherical to subspherical, average 7.5 × 7.8 m and possess a compact globular sporocyst residuum; the Stieda body is absent. Eimeria phelsumae n. sp. was recovered from the giant day gecko, Phelsuma madagascariensis grandis, from Madagascar, which harboured a simultaneous infection of E. brygooi. The oöcysts measured 32 × 15 m and are cylindroidal without polar granules, a micropyle or oöcyst residuum, or a Steida body. The sporocysts are ellipsoidal and average 9.8 × 7 m, with a loosely clumped, granular sporocyst residuum; the Steida body is absent. Eimeria leiocephali n. sp. was discovered in the faeces of the ornate ground iguana, Leiocephalus barahonensis, from Haiti. The oöcysts are spherical to subspherical, 21 × 19 m, and contain a number of polar granules (n > 5); a micropyle and oöcyst residuum are absent. The sporocysts are spherical, 8 m in diameter and lack a sporocyst residuum. Eimeria turcicus and E. lineri were found in faeces of Hemidactylus turcicus turcicus from the host's country of origin, Turkey.     

Morphology and evolutionary implications of the annual cycle of secretion and sperm storage in spermathecae of the salamander Ambystoma opacum (Amphibia: Ambystomatidae)

Females of the marbled salamander, Ambystoma opacum, store sperm in exocrine glands called spermathecae in the roof of the cloaca. Eggs are fertilized by sperm released from the spermathecae during oviposition. Some sperm remain in the spermathecae following oviposition, but these sperm degenerate within a month and none persists more than 6 mo after oviposition. Thus, sperm storage between successive breeding seasons does not occur. Apical secretory vaculoes are abundant during the fall mating season and contain a substance that is alcian blue+ at pH 2.5. Production of secretory vacuoles decreases markedly after oviposition, and the glands are inactive by the summer months. Ambystoma opacum is a terrestrial breeder, and some mating occurs prior to arrival at pond basins where oviposition occurs. Mating prior to arrival at the ovipository site may prolong the breeding season, leading to fitness implications for both males and females. Females have opportunities for more matings, and the possibilities for sperm competition in the spermathecae are enhanced. © 1995 Wiley-Liss, Inc.     

New species of Eimeria (Apicomplexa: Eimeriidae) from the domesticated goat Capra hircus in New Zealand

Three new species of the genus Eimeria Schneider, 1875 are described from the faeces of domesticated goats in New Zealand. Oöcysts of E. capralis n. sp. are ellipsoidal, 29.2 × 19.7 (25–34 × 17–24) μm, with a distinct micropylar cap. The sporocysts are broadly ovoid, the Stieda body is present and the sporocyst residuum consists of many scattered granules. Sporozoites lie lengthwise head to tail in the sporocyst. Oöcysts of E. masseyensis n. sp. are broadly ellipsoid to ovoid, 22.3 × 17.4 (18–25 × 15–19) μm, with a distinct micropylar cap. The polar granules are shattered into fine granules, the sporocysts are elongate ovoid and the Stieda body is present. Oöcysts of E. charlestoni n. sp. are ellipsoidal, 22.9 × 17.4 (20–25 × 16–19) μm, with no micropylar cap. Its oöcysts are distinctive, with elongate sporocysts containing very prominent refractile bodies.     

New Species of Eimeria (Protozoa: Eimeriidae) from Malaysian Squirrels*

SYNOPSIS. In a survey of 520 squirrels of 19 species from Malaysia, 6 new species of Eimeria were found. Three are described from the subfamily Petauristinae: E. kylopetis n. sp. from the red-cheeked flying squirrel Hylopetes spadiceus; E. aeromysis n. sp. from the large black flying squirrel Aeromys tephromelas; E. malayensis n. sp. from the spotted giant flying squirrel Petaurista elegans. Three are described from the subfamily Sciurinae: E. hippuri n. sp. from the horse-tailed squirrel Sundasciurus hippurus; and E. notati and E. pahangi n. spp. from the plantain squirrel Callosciurus notatus.     

New Species of Eimeria (Protozoa: Eimeriidae) from Malaysian Rats*

SYNOPSIS. Four new species of Eimeria were found in a survey of 255 rats of 14 species in Malaysia. E. tikusi n. sp. and E. edwardsi n. sp. are described from Edwards' rat Rattus edwardsi. The ellipsoidal, single-layered oocysts of E. tikusi average 30.3 by 24.4 μ. A micropyle is absent; a polar granule is present. Ovoid sporocysts average 14.2 by 9.8 μ. A sporocyst residuum and Stieda body are present. The ovoid, 2-layered oocysts of E. edwardsi average 29.1 by 21.8 μ. A micropyle is present; a polar granule is absent. Ellipsoidal to ovoid sporocysts average 14.5 by 6.5 μ. A sporocyst residuum is present; Stieda body is small or absent. E. surifer n. sp. is described from the red spiny rat Rattus surifer. Its ellipsoidal 3-layered oocysts average 34.7 by 24.8 μ. A micropyle is absent; a polar granule is present. The ellipsoidal sporocysts average 15.4 by 9.5 μ. A sporocyst residuum, Stieda body and sub-Stieda body are present. E. sabani n. sp. is described from the long-tailed giant rat R. sabanus. Its ellipsoidal 2-layered oocysts average 28.5 by 21.7 μ. A micropyle is absent; a polar granule is present. The ellipsoidal-to-ovoid sporocysts average 11.9 by 8.0 μ. A sporocyst residuum and Stieda body are present.     

Coccidian Parasites (Apicomplexa: Eimeriidae) of Nerodia spp. (Serpentes: Colubridae), with a Description of a New Species of Eimeria

Eimeria conanli n. sp. (Apicomplexa: Eimeriidae) is described from intestinal contents and feces of Nerodia erythrogaster transversa and N harteri harteri from northcentral Texas. Oocysts of the new species are ellipsoid in shape. 17.9 × 13.0(15–21 × 12–15) μm, with a smooth, thin, single-layered wall; shape index 1.4 (1.2–1.5). One to several (usually 2) polar granule(s) and an oocyst residuum are present, but a micropyie is absent. Sporocysts are elongate, 12.9 × 5.2 (13–15 × 5–6) -m, apparently without a true Stieda body structure. Each sporoeyst contains an ellipsoid residuum, 3.9 × 3.2 (3–6 × 2–4) μm, and elongate sporozoites, 11.4 × 2.5 (10–14 × 2–3) μm in situ, each with a spherical or subspherical anterior refractile body and spherical to ellipsoid posterior refractile body. In addition to the new species, oocysts of 4 previously described eimerians from colubrid snakes were found in these hosts.     

A new species of Eimeria (Apicomplexa: Eimeriidae) from the western hognose snake, Heterodon nasicus (Serpentes: Xenodontidae), from Texas

A new species of coccidian (Apicomplexa: Eimeriidae) is described from the feces of a western hognose snake Heterodon nasicus (Serpentes: Xenodontidae) collected from Texas, and housed in the collection of the Zoological Society of London. Oocysts of Eimeria mchenryi n. sp. are cylindrical, 35.0 ± SD 1.4 (32-37) × 17.0 ± 0.7 (16-18) μm; the shape index (length/width) is 2.05. A micropyle, oocyst residuum, and polar granule are absent. Sporocysts are subspherical 9.3 (7-11.5) × 7.7 (6-9) μm, with a shape index of 1.2. There is a sporocyst residuum, but the new species is lacking Stieda bodies. The new species is distinct from those previously named from the Xenodontidae and the allied family, Colubridae.     

A new species of Eimeria (Apicomplexa: Eimeriidae) from the eastern pipistrelle, Perimyotis subflavus (Chiroptera: Vespertilionidae), in Arkansas

During November 2009 and March 2010, 20 adult eastern pipistrelles, Perimyotis (= Pipistrellus) subflavus, were collected from Polk County, Arkansas, and their feces were examined for coccidian parasites. Two (10%) of the bats were found to be passing oocysts of an undescribed species of Eimeria. Oocysts of Eimeria heidti n. sp. were ovoidal to ellipsoidal, 26.1 × 20.5 μm (23-31 × 18-23 μm), with a bilayered wall, externally rough, internally smooth, and with a shape index of 1.3. Micropyle and oocyst residuum were absent, but a subspherical polar granule was often present. Sporocysts were ovoidal, 13.0 × 8.8 μm (11-15 × 7-13 μm), the shape index was 1.6, a Stieda body was present and sub-Stieda and para-Stieda bodies were absent. A sporocyst residuum consisting of multiple globules dispersed along the perimeter of the sporocyst and between the sporozoites were present, sporozoites were elongate, with a subspherical anterior refractile body and elongate posterior refractile body; a nucleus not discernible. This is the second coccidian reported from this host and the fourth instance of a coccidian species reported from an Arkansas bat.     

Early Development of Eimeria Papillata (Apicomplexa: Eimeriidae) In the Mouse

ABSTRACT Early development of Eimeria papillata (Apicomplexa) in the mouse was evaluated using Nomarski interference-contrast and brightfield microscopy. Sporozoite-shaped meronts, which were motile and contained a large posterior refractile body and a smaller anterior refractile body, were observed entering and leaving host cells in the jejunum of an experimentally infected mouse at 26 h post inoculation (HPI). However, early developmental stages were not observed in tissue of the duodenum, ileum, cecum and colon. the mean length and width of these meronts (n = 20) were 12.0 μm and 3.7 μm, respectively. Spherical or subspherical meronts containing crescent-shaped merozoites were observed at 36 HPI.     

Early development of Eimeria papillata (Apicomplexa: Eimeriidae) in the mouse

Early development of Eimeria papillata (Apicomplexa) in the mouse was evaluated using Nomarski interference-contrast and brightfield microscopy. Sporozoite-shaped meronts, which were motile and contained a large posterior refractile body and a smaller anterior refractile body, were observed entering and leaving host cells in the jejunum of an experimentally infected mouse at 26 h post inoculation (HPI). However, early developmental stages were not observed in tissue of the duodenum, ileum, cecum and colon. The mean length and width of these meronts (n = 20) were 12.0 microns and 3.7 microns, respectively. Spherical or subspherical meronts containing crescent-shaped merozoites were observed at 36 HPI.     

A new species of Eimeria Schneider, 1875 (Apicomplexa: Eimeriidae) from Carlia spp. (Sauria: Scincidae) from Papua New Guinea

A new species of Eimeria Schneider, 1875 from rainbow skinks, Carlia ailanpalai Zug and Carlia eothen Zug is described from specimens collected in Papua New Guinea (PNG). Oöcysts of Eimeria zugi n. sp. from one of one (100%) C. eothen are ellipsoidal to cylindroidal, with a smooth, colourless, bi-layered wall, measure 25.1 × 15.5 μm and have a length/width ratio of 1.6. The micropyle and the oöcyst residuum are absent, but a polar granule is present. The sporocysts are ovoidal to ellipsoidal and 10.3 × 7.1 μm in size and do not contain Stieda, sub-Stieda or para-Stieda bodies; and the sporocyst residuum is composed of a compact mass of large globules. The sporozoites are elongate, 12.8 × 2.9 μm in size, and contain anterior and posterior refractile bodies with a nucleus between them. This is the ninth species of coccidium described from skinks from PNG, and the new species described herein is apparently endemic to the skink genus Carlia (Gray).     

Spermathecal cytology of Ambystoma opacum (Amphibia: Ambystomatidae) and the phylogeny of sperm storage organs in female salamanders

Sperm storage glands, spermathecae, were examined from mated female Ambystoma opacum during the breeding season. No differences occur in the spermathecal ultrastructure of individuals sacrificed prior to oviposition and those sacrificed within 3 days of removal from tended clutches of recently oviposited eggs. The simple tubuloalveolar glands produce two types of secretory vacuoles. Apical secretory vacuoles contain glycosaminoglycans for export into the lumen to bathe stored sperm, perhaps providing the chemical/osmotic environment necessary for sperm quiescence. The other type of secretory vacuole contains an unsaturated lipid that is produced for export into the connective tissue surrounding the spermathecae. The role of this secretion may involve the contraction of myoepithelial cells, resulting in sperm expulsion. Some sperm undergo degradation in the spermathecal epithelium, and an interepithelial leukocyte was observed in one specimen. Apical secretory vacuoles and sperm are absent from the spermathecae of a specimen sacrificed 62 days after removal from a tended egg clutch. This is the first report on the spermathecal cytology of a salamander from the Ambystomatidae, and comparisons with salamanders from other families provide a morphological basis for considering spermathecae polyphyletic within the Caudata. © 1993 Wiley-Liss, Inc.     

A new species of Eimeria (Apicomplexa, Eimeriidae) from the weedy sea dragon Phyllopteryx taeniolatus (Osteichthyes: Syngnathidae)

A new species of intestinal coccidian is described from the weedy or common sea dragon Phyllopteryx taeniolatus housed at the New England Aquarium in Boston and at the Shedd Aquarium in Chicago, USA. Live oocysts of Eimeria phyllopterycis sp. n. are spherical, 30.9 (28.0-34.4) microm, with a thin, single-layered wall. Both a micropyle and oocyst residuum are absent and a large polar granule is sometimes present. Sporocysts are ellipsoidal and elongate, 24.3 x 10.4 (23.4-25.6 x 9.2-11.2) microm, with Stieda and substieda bodies; shape index (length/width) 2.33 (2.14-2.70). A sporocyst residuum is present, consisting of numerous granules of various sizes. Sporozoites each possess 3 refractile bodies. Preliminary evidence suggests that the coccidian may affect the health of sea dragons; however, it could not be determined whether this parasite caused significant morbidity or mortality.