Some biological consequences of environmental change: A study using barnacles (Cirripedia: Balanomorpha) and gum trees (Angiospermae: Myrtaceae)

Uniformitarianism permits understanding of the past on the basis of the present, and modeling the future through consideration of the fossil record. The present paper addresses the impact environmental (climatic) change has had on acorn barnacles and eucalyptus trees. Acorn barnacles (Balanomorpha) are first recorded after the K/T mass-extinction event. In the Paleogene, rapid radiation resulted in their occupying most marine environments. That balanomorphs survived both the Paleocene–Eocene thermal maximum and the Pleistocene glaciation is testament to their ability to adapt to opportunities; they are known from the littoral (Chamaesipho) to depths of 3600 m (Tetrachaelasma) and within this from diverse substrates: rock, wood and miscellaneous flotsam, plus in symbiosis or commensalism with most larger marine organisms. Darwin's (1854) view of the late Tertiary as the age of barnacles is reflected in their diversity, distribution and biomass. Barnacles are contrasted with the Australian Myrtaceae: plants ranging from woody shrubs to tall trees. The most significant is Eucalyptus sensu lato, which typifies Australia's flora, and is characterized by aromatic leaves that produce eucalyptol. Eucalyptus has evolved strategies that result in its domination of Australian open woodlands: these include production of highly flammable eucalyptol oil (with a flashpoint of 49 °C) and an unprecedented ability to regenerate following forest fires. Gum trees and barnacles first appear in the Paleogene, their earliest records are Australasian, and they both demonstrate extraordinary resilience when environmental conditions are optimal.     

Larval development of Spondyliosoma emarginatimi (Cuvier & Valenciennes) (Pisces: Sparidae) from southern Africa

The larval development of the southern African endemic sparid Spondyliosoma emarginatum is described and illustrated from specimens collected in Algoa Bay and the Swartkops, Sundays and Swartvlei estuaries of the Cape Province. S. emarginatum has demersal eggs. Preflexion larvae are moderately elongate (BD = 18–23% BL) with body depth increasing to 31 % BL in postflexion stages. The head is rounded and the snout blunt but becomes more elongate in postflexion stages. There are short spines on the preoperculum. Flexion occurs at about 6 mm BL and postflexion larvae are characterized by distinct medio-lateral pigmentation. Osteological development is described from a series of cleared and stained specimens. All fins have the adult complement of spines and rays by 12 mm BL. The larvae of S. emarginatum are compared with those of the European S. canthurus and other southern African sparids.     

Cooperia pectinata (Nematoda: Trichostrongylidae) in New Zealand

Cooperia pectinata, a nematode parasite hitherto undetected in New Zealand, was recovered from the small intestine of a six-month-old red deer (Cervus elaphus) born on a deer farm in Taihape. The source of this infection is unknown but it seems likely that it originated from feral stock.     

Description of a new species of Afroedura (Loveridge) (Reptilia: Gekkonidae) from the south-western Cape

A new gekkonid species, Afroedura hawequensis, is described from the south-western Cape (South Africa). The three species groups recognized in the genus are discussed.     

A new species of Heterixalus (Amphibia: Hyperoliidae) from western Madagascar

A new species of hyperoliid frog, Heterixalus carbonei n.sp., is described from the Antsingy forest inwestern Madagascar. It is characterized by an advertisement call consisting of long and regular note series. The only other Heterixalus with a similar call structure, H. betsileo from higher altitudes in eastern Madagascar, has distinctly shorter notes. After recent discoveries of the occurrence of H. luteostriatus and H. tricolor in western Madagascar, the new species brings the number of Heterixalus known from western Madagascar to three.     

Protogynous hermaphroditism in Chrysoblephus laticeps (Cuvier) and C. cristiceps (Cuvier) (Teleostei: Sparidae)

A histological study of the gonads of two sparid fishes, Chrysoblephus laticeps and C. cristiceps showed that these species are protogynous hermaphrodites. Both species are also monandric in which all males are derived from functional females. Intersexual individuals were restricted to a narrow size range between females and males, and no evidence for simultaneous hermaphroditism was found. Similar to other sparids, the development of the ovary and testis was delimited by a connective tissue layer.     

A new species of Asemonea from Zambia (Araneae: Salticidae: Lyssomaninae)

A new spider species from Zambia belonging to the poorly-known genus Asemonea, is described. It appears to be related to Asemonea maculata from the Ivory Coast.     

The eggs of some blood-flukes (Trematoda: Schistosomatidae) from South African birds

The eggs of three species of avian schistosomes were recovered from indigenous South African birds. Gigantobilharzia sp. was recorded from the kelp gull, Larus dominicanus and the gannet, Morus capensis; Austrobilharzia sp. from L. dominicanus, and Trichobilharzia sp. from the spurwing goose, Plectropterus gambensis, the Egyptian goose, Alopochen aegyptiacus and L. dominicanus. The morphology of these eggs is compared to that of described species of avian schistosomes.     

Mitochondrial DNA sequence analyses in Bornean sucker fishes (Balitoridae: Teleostei: Gastromyzontinae)

Phylogenetic relationships among Bornean sucker fishes (Teleostei: Balitoridae: Gastromyzontinae) were investigated by comparing cytochrome b gene sequences from eight species. The results were in general agreement with previous morphology‐based studies. It was found that the genera Gastromyzon and Neogastromyzon are both monophyletic and that the Chinese homalopterid Crossostoma lacustre (Homalopterinae) is not related to the Bornean species. This molecular‐level study of cytochrome b gene variation in Bornean gastromyzontins will undoubtedly help to shed light on the molecular systematics of this unique freshwater fish.     

Two new records of helminth parasites of domestic cat from Uruguay: Alaria alata (Goeze, 1782) (Digenea, Diplostomidae) and Lagochilascaris major Leiper, 1910 (Nematoda, Ascarididae)

Eight helminth taxa were recovered from the necropsy of four stray domestic cats from Colonia Miguelete, county of Colonia, Uruguay. Two of them are recorded for the first time for domestic cats in that country: Alaria alata (Goeze, 1782) from the small intestine (which is also the first trematode species found in domestic cat in Uruguay), and Lagochilascaris major Leiper, 1910 from the pharynx. The remaining helminth species found were Toxocara mystax (Zeder, 1800) and Spirometra sp. from the small intestine, Trichuris serrata (von Linstow, 1879) from the caecum, Eucoleus aerophilus (Creplin, 1839) from the trachea, and Pearsonema feliscati (Diesing, 1851) from the urinary bladder. Moreover, four female specimens of an unidentified Spiruroidea were collected from the stomach and small intestine of one host.     

Evolution of Acoustic Behaviour in African Bufo (Anura: Bufonidae)

Mating calls are known for 29 species of African Bufo belonging to 11 species groups. Twenty-five African species, representing eight species groups (including four groups or complexes having 2N=22) have calls which Martin (1972) termed Type I. This call type is also found in Schismaderma carens, Nectophrynoides tornieri and N. occidentalis. It is known in only four species of Bufo outside Africa and in Odontophrynus americanus which is thought to be closely related to leptodactylids that gave rise to the genus Bufo. Four African species of Bufo have Type II calls.

Geographic distribution of three call types indicates large radiations of one or two call types in South America, North America and Africa. The European and Asian Bufo faunas appear to be derived primarily from American radiations.

The radiation of bufonids in Africa appears to be equal to that of South America. An explanation of this may be that Bufo or its progenitor evolved prior to the continental separation of South America and Africa.     

Redescription and molecular characterisation of the fish parasitic isopod Norileca indica (Milne Edwards, 1840) (Crustacea: Isopoda: Cymothoidae) with a key to the genus

Norileca indica (Milne Edwards, 1840) is fully redescribed based on ovigerous females collected from Maputo Bay, Mozambique, from the branchial cavity of the fish host Selar crumenophthalmus Bloch, 1793. An identification key to the species of Norileca Bruce, 1990 is given. Furthermore, a fragment of the mitochondrial cytochrome oxidase I (COI) gene from N. indica was sequenced for the first time. This is the first molecular characterisation of a species of Norileca.     

Dietary overlap in plocepasserine weavers (Aves: Ploceidae)

The blood flow in the ear of the African elephant Loxodonta africana was measured In anaesthetized animals using the dye dilution technique at the same time as the arterio-venous temperature difference. The calculated heat loss from the ear is shown to be a substantial proportion of the total metabolic heat-loss requirement calculated from body surface area estimations. Reasons are advanced for believing that ear blood flow is controlled in the interests of thermoregulation. Behavioural fanning activity and the large ear surface area and surface to volume ratio suggest that this organ is of major importance in thermoregulation under warm environmental conditions.     

The prevalence of Proctoeces (Trematoda: Fellodistomidae) metacercarial infections in the brown mussel Perna perna (Bivalvia: Mytilidae) around the southern African coast

Unencysted trematode metacercariae of the genus Proctoeces were found embedded in the mantle tissue and visceral mass of the intertidal mussel Pema pema. Data on the prevalence and intensity of infection in southern African populations of Pema are presented. Results from a geographic survey indicated that Proctoeces infections were more prevalent in the region Port Elizabeth to Isilaka. At the majority of sites both prevalence and intensity of infection increased in conjunction with host size. Detailed studies of mussels from Dwesa failed to show seasonal changes in metacercarial infection. A strong relationship, however, was found between sex of host and parasitic infection, with female mussels harbouring the most metacercariae. The most heavily infected mussels examined came, ironically, from two nature reserves situated on a stretch of coastline where otherwise unprotected mussel stocks are subjected to intense exploitation by man. The possible pathogenic effects of Proctoeces on such highly stressed mussel populations clearly merits further attention.     

The feeding ecology of Ambassidae (Osteichthyes: Perciformes) in Natal estuaries

The diets of three species of Ambassis in six estuaries of southern Africa were investigated using four methods of stomach content analysis. Diets varied from one estuary to another as the faunal composition changed according to physical conditions. Ecological separation among the species is achieved to a large extent through diet alone. While all Ambassis feed mainly on a wide variety of zooplankters, Ambassis productus and A. natalen-sis are also piscivorous and insectivorous respectively. Seasonal analysis of diet showed that A. gymnocephalus feeds mainly on fish eggs during winter (June-August). The possible impact of egg predation on fish numbers at St Lucia is discussed. Feeding periodicity was investigated using dry mass and volumetric methods. All Ambassis showed similar bimodal feeding intensities during the night with peaks in early evening and early morning. Food selection at different levels in the water column showed that all Ambassis feed mainly on food in suspension. Additionally A. natalensis feeds on surface prey while A. productus takes ben-thic prey. It is postulated that interaction between Ambassis and filter-feeding planktivores in St Lucia is minimal due to feeding strategies and feeding periodicity. In addition the impact of the piscivorous predatory role played by Ambassis on estuarine fish communities is emphasized.     

Acaricidal effects of the essential oil of Origanum minutiflorum (Lamiaceae) against Rhipicephalus turanicus (Acari: Ixodidae)

The acaricidal effects of the volatile essential oil Origanum minutiflorum O. Schwarz & P.H. Davis (Lamiaceae) against adult Rhipicephalus turanicus was evaluated at a variety of concentrations and exposure times. Generally tick mortality increased with concentration and exposure. Ticks exposed to vapors from cotton wicks containing at least 10 μl/L resulted in complete (100%) mortality at 120 min. The major constituent of essential oil obtained from the plant material of O. minutiflorum was carvacrol.     

Apical Shell Sculpture of some African Freshwater Limpets (Mollusca: Basommatophora: Ancylidae)

Physa marmorata, originally described from the Lesser Antilles, was introduced into Africa before 1900 and has previously been reported from Bénin, Togo, Ghana, Nigeria and South Africa. Here we show that it is also common in temporary ponds, fish ponds, dams and streams in the La Mé and Agnéby basins, southern Ivory Coast. Population dynamics were studied in one river in Agboville and in one permanent pond in Attinguié. Fortnightly sampling carried out throughout 2005 at the two sites revealed two main periods of recruitment: during the first rainy season in July and during the second rainy season in October. In the Agboville river, a positive association was found between P. marmorata densities and percentage cover of the aquatic plants Ipomea aquatica and Pistia stratiotes. Similar associations were found between P. marmorata densities and both high water redox potential and rainfall values. However in the Attinguié pond, a negative association was observed between Melanoides tuberculata and P. marmorata densities. We discuss the timing, status and potential consequences of the invasion of this snail species into the Ivory Coast and the African continent.     

Observations on the reproductive cycles of Cellana capensis (Gmelin, 1791) and Patella concolor Krauss, 1848 (Gastropoda: Prosobranchia: Patellidae)

The reproductive periodicities of the patellid limpets Cellana capensis and Patella concolor were determined from changes in macro-and microscopic appearance of the gonads over a 14-month period. Both species appear to have protracted breeding periods with several peaks in spawning activity. Problems encountered with the application of standard sampling and analytical methods to species with such cycles are discussed.