Abstract

This study focused on the neomatamorphs of P. auritus. With the aim to characterize the snout vent length of neometamorphs and to assess the relationship between snout vent length and body size. Adults were collected and brought to the laboratory alive.

At the lab, frogs were placed in a plastic transparent container with a screen to avoid the frog escaping. Tissue paper was placed at the bottom of the container the whole was moisturized with aged tap water. Adult frogs were fed with fruit flies. Frog readily laid or assisted reproduction was undertaken.

Tadpoles were grown to neometamorphs and snout vent length was measured. Out of 58 neometamorphs measured, the snout vent length increased with body size. Future endeavours need a holistic approach involving all developmental stages of tadpoles from the range of this species to provide more insight related to the ecology and biology of P. auritus.

CHAPTER ONE

INTRODUCTION AND LITERATURE REVIEW

1.1 INTRODUCTION.

The golden puddle frog (Phrynobatrachus auritus) belongs to the Phrynobatrachidae family. This frog lives on the floor of secondary and riparian rainforests and is often associated with rivers. It is not found in open habitats outside forests (Amiet et al., 2004).

Two Phrynobatrachus species. Phrynobatrachus auritus and Phrynobatrachus cornutus reach submontane elevations on Bioko Island (up to 1200–1300 m) but are present only at lowland elevations on Cameroon mainland (Zimkus, 2009).

Most species of Phrynobatrachus are restricted to one of five sub-Saharan regions and are distributed within the Eastern, Central, and Western zones with far fewer species in Southern Africa. P. auritus ranges from southeastern Nigeria and southern Cameroon, east to eastern Democratic Republic of Congo, western Uganda and Rwanda.

It is presumed to occur in the Cabinda Enclave of Angola. There is an absence of records through much of the Congo Basin, but this is probably due to under-sampling (Amiet et al., 2004).

Aclade endemic to the mountains of western Cameroon and eastern Nigeria. Part of the geologic rift zone termed the Cameroon Volcanic Line, supports the view that mountainous regions have acted as centres of speciation (e.g. Zimkus 2009; Zimkus et al., 2010).

Zimkus et al., (2012) report that most Phrynobatrachus species breed in small bodies of water and have aquatic eggs with free-living, feeding tadpoles. Clades that exhibit alternate reproductive modes have lower diversification rates than those that deposit eggs aquatically.

Most puddle frogs deposit hundreds to thousands of eggs in ponds, streams, or pools, but a small number of species deposit small clutches of eggs in stagnant water found in tree holes, in empty fruit capsules, within snail shells, or terrestrially (Zimkus et al., 2012) and these eggs hatches into tadpoles.

Other species such as P. chukuchuku, P. jimzimkusi, and P. manengoubenis are endemic to parts of the Cameroonian Volcanic Line. Most known Phrynobatrachus tadpoles are very cryptic in colour and secretive in behaviour. One, however, is aposematically coloured (Rödel et al., 2009).

Habitat choice, reproduction strategy, and developmental mode vary among Phrynobatrachus species. Unfortunately, tadpoles have so far been described as only 15 out of 87 Phrynobatrachus species (Channing et al., 2012).

Tadpoles of amphibians have 46 developmental life stages.

1.2 LITERATURE REVIEW

1.2.1 Biology of tadpoles

Phrynobatrachus auritus is a species in the class Amphibia. Amphibia include creatures such as: frogs, toads, newts, and salamanders and are vertebrates. P. auritus natural habitats are subtropical or tropical moist lowland forests, rivers, freshwater marshes, intermittent freshwater marshes, and are threatened by habitat loss due to deforestation. P auritus has other common names such as African golden puddle frogs or African river frogs. Classification of P.auritus

Kingdom: Animalia

Phylum: Chordata

Class: Amphibia

Order: Anura

Family: Phrynobatrachidae

Genus: Phrynobatrachus

Species: P. auritus

Tadpoles are odd organisms with a composite head and a body, a muscular tail without vertebrae, and a dorsal and ventral fin that lacks bony supports. They are also described as aquatic larva or immature forms of frogs and toads, after the development of the internal gills and before the appearance of the forelimbs and the resorption of the tail.

Phrynobatrachus tadpoles are usually cryptically (brownish) coloured, currently, approximately 89 species, occurring throughout Sub-Saharan Africa (Frost, 2o16).  Despite the fact that members of  this  genus inhabit  habitats  ranging  from dry savannas  to  primary rain forests  and  a wide  range of  altitudes,  their  reproductive  patterns are  astonishingly uniform  as far  as it  is  known  (Altig and McDiarmid, 1999).

With the exception of Phrynobatrachus guineenis that deposits its few large eggs in small water-filled tree holes (Rodel, 1998), all other species, lay clutches of several hundred to a  few thousand small eggs that float in a single layer on the surface of stagnant or slow running water  (Stewart, 1967; Wager, 1986; Rodel, 2000a). All tadpoles are exotrophic, lentic, and benthic (Altig and McDiarmid, 1999; Rodel, 2000a,).

They hatch from eggs and become tadpoles they then develop back legs, front legs, and finally, their tails disappear and they become froglets. Monitoring tadpole populations may be more feasible than monitoring adult frogs because for many species tadpoles are present in habitats for longer periods of time than adults and thus, maybe the life stage encountered most often (Altig, et al., 1998).

For many species of frogs that occur over a wide geographic range there is considerable variation in tadpole appearance and size across the range. In addition, tadpole appearance may vary over a small geographic scale due to habitat characteristics such as the amount of tannins in water or the presence of fish predators.

Tadpoles are able to live in the rainforest, where one can hear frogs croaking, sometimes frogs lay them in unused pools or ponds in backyards, and usually 9×9 meter shallow ponds. In water, tadpoles can be found in lakes and ponds.

Tadpole’s food varies according to their species. Some eat mostly algae, whereas others eat frog eggs provided by a female, and still other cannibalize other tadpoles. Tadpoles eat through their small mouths, located on the ventral surface of the head. In general, tadpoles eat almost anything you can think of. They will eat bacteria, lettuce, algae, insects, and fish.

One of the best foods to feed them is lettuce. Different species of tadpoles varies in their sizes. Most North American frogs’ and toads’ tadpoles will be 1 centimetre up to 1 inch. The bullfrog can grow to two inches. During metamorphosis, Phrynobatrachus are usually less than 1 cm body length (Lamotte and Dzieduszycka, 1958; de SáChanning, 2003; Rödel 1998, 2000)

1.2.2 Morphology of tadpoles

Tadpoles are small tiny invertebrate organism with a composite head, body and tail.

According to Altig and McDiarmid (1999), Phrynobatrachus tadpoles are exotrophic, lentic and benthic; have tooth row formulae of 1//2, 1//3, 1//1+1/3, or 1/1+1//2; anterior ventral mouth openings; uniserial marginal papillae with large dorsal (anterior) gaps; ventral papillae that are sometimes elongated; sub marginal papillae on the lower lip; no or lateral disc emaginations; nares that are closer to the snout than to the eyes; medial vent tubes; dorsally positioned eyes; sinistral spiracles; upper jaws with wide, prominent medial convexity; lower jaw that are open U-shaped.

Body junction; oval to depressed bodies; dark colours; and are small to medium sized at an advanced stage of development (20–35 mm) and low dorsal fins with pointed tips, emerging near the dorsal tail. The tail lacks vertebrae.