Northwestern Madagascar Research Articles

Distribution and Conservation Status of Two Newly Described Cheirogaleid Species, Mirza zaza and Microcebus lehilahytsara

The northern giant mouse lemur, Mirza zaza Kappeler and Roos in Kappeler et al., 2005, and Goodman's mouse lemur, Microcebus lehilahytsara Roos and Kappeler in Kappeler et al., 2005, are known from the region of the Ampasindava peninsula in northwestern Madagascar, and Andasibe and surrounding regions in east-central Madagascar, respectively. The presence of M. zaza in protected areas has yet to be confirmed, but it may occur in the Manongarivo Special Reserve and the Tsingy de Namoroka National Park. Microcebus lehilahytsara occurs in the Analamazaotra Special Reserve and Mantadia National Park. In this paper, we review what little is known of these two species in terms of their distributions and conservation status. Mirza zaza is possibly Vulnerable, following the IUCN Red List criteria, whereas Microcebus lehilahytsara is Data Deficient.

Habitat difference in food abundance possibly causes within-population variation in the timing of breeding in the Madagascar paradise flycatcher (Terpsiphone mutata)

Within-population variation in the timing of breeding in the insectivorous Madagascar paradise flycatcher, Terpsiphone mutata (L., 1766), was investigated in a dry forest of northwestern Madagascar. The study area was divided into two sites (namely, A and B) based on the distance from the waterside. An examination was conducted to determine whether the date of egg laying varies between the two sites, and if it does vary, what are the environmental factors that affect the variation. The females started egg laying significantly earlier at site B than at site A. The two sites are located in a continuous forest; hence, photoperiod and precipitation would not differ between them. The number of insects was higher at site B than at site A. The difference in the temperature was not considered to be the cause of the variation in the date of egg laying. Age structure of the females was not likely to differ between the sites. Therefore, the variation in the date of egg laying is considered to be caused by the difference in food abundance that is associated with the relative distance from the waterside.

NEW AND LITTLE-KNOWN GASTROPODS FROM THE ALBIAN OF THE MAHAJANGA BASIN, NORTHWESTERN MADAGASCAR

Thirty-one gastropod species and one type of isolated larval shell are described from a quarry near Ambatolafia in the Mahajanga Basin, northwestern Madagascar. The ammonite fauna indicates a lower Albian age of the fauna (Cleoniceras besairiei Zone). The taxonomic position of the species described earlier is reviewed, incorporating new data on shell structure and protoconch morphology. Twelve species and one genus are new, with four species described in open nomenclature. The oldest hitherto known representatives of Cocculina sensu lato, Iphitus, Conjectura, Entomope, Tomura, and possibly Vatopsis and Paladmete, are described. Nacre is documented in a species of Semisolarium, providing further evidence for the position of this genus within the Vetigastropoda. Eight of the species occur also in the Cretaceous of Europe or are tentatively assigned to European species. Three species have close relatives in the Aptian/Albian of Japan, one species may have relations to the Albian of Texas. The new genus is Mahajangina (family uncertain) for a species having a small, trochispiral teleoconch with spines on the periphery, and a conical, bicarinate larval shell. The new species are: Cirsocerithium collignoni, Zardinistylus betsibokaensis, Pommerozygia mahajangensis, Conjectura minuta, Buvignieria berwaldi, Mahajangina weitschati, Entomope crassilabrum, Paladmete? rasoarinoroae, Tomura ambatolafiensis, Carinathilda parviruga, Carinathilda bandeli, and Gymnothilda pagodoidea.

Feeding Ecology of Sympatric Mouse Lemur Species in Northwestern Madagascar

We performed a comparative pilot study on vertical space use and feeding ecology of 2 closely related sympatric mouse lemur species in northwestern Madagascar. We recorded feeding behavior and the use of vertical forest strata for 6 gray and 4 golden-brown mouse lemur females that we followed for 120 h. We carried out feeding experiments and analyzed fecal samples for food remains. Both species showed no significant difference in use of forest strata. They had a similar overall diet, with insect secretions and gum as main plant food resources; arthropod remains occurred in about half of all fecal samples. Both lemurs used in common >50% of the plant species that each consumed, which accounts for ≥70% of all individual plants used. However, both species used >40% of their feeding plant species exclusively and seemed to differ in their degree of specialization on certain plant species.

LATE CRETACEOUS TERRESTRIAL VERTEBRATES FROM MADAGASCAR: IMPLICATIONS FOR LATIN AMERICAN BIOGEOGRAPHY1

The Mahajanga Basin Project, initiated in 1993 and centered in Upper Cretaceous strata of northwestern Madagascar, has resulted in the discovery of some of the most complete, well-preserved, and significant specimens of Late Cretaceous vertebrate animals from the Southern Hemisphere and indeed the world. Among the most important finds are various specimens of crocodyliforms, non-avian dinosaurs, and mammals; these finds have the potential to provide key insights into the biogeographic and paleogeographic history of Gondwana. Madagascar has been physically isolated from Africa for over 160 million years and from all other major landmasses for more than 85 million years. The closest known relatives of many of the Late Cretaceous Malagasy taxa are penecontemporaneous forms from South America (primarily Argentina) and India, thus documenting a previously unrecognized high level of cosmopolitanism among Gondwanan vertebrates near the end of the Cretaceous. The family-level taxa that are shared among Madagascar, South America, and the Indian subcontinent are not known from penecontemporaneous horizons in mainland Africa, but it cannot yet be confidently determined if this is due to differential extinction, poor sampling, true absence (i.e., the taxa were never present on Africa), or some combination thereof. Nonetheless, currently available geologic and paleontologic data are most consistent with the Africa-first model, suggesting that Africa was the first of the major Gondwanan landmasses to be fully isolated prior to the Albian/Cenomanian boundary, and that its terrestrial vertebrate faunas became progressively more provincial during the Cretaceous, while those on other Gondwanan landmasses remained relatively cosmopolitan until the later stages of the Late Cretaceous.

New treefrog of the genusBoophisTschudi 1838 from the northwestern rainforests of Madagascar

A new species of the Boophis goudoti group is described from elevations of 680-1100 m in the Tsaratanana and Manongarivo Massifs in north-western Madagascar. Boophis axelmeyeri n. sp. is morphologically similar to B. burgeri Glaw & Vences 1994, but differs by its eye coloration which has a red outer iris area. It is strongly differentiated in a fragment of the mitochondrial 16S rRNA gene (6.6% pairwise sequence divergence) and has advertisement calls with longer note durations as compared to B. burgeri. Specimens from the Marojejy Massif in north-eastern Madagascar, previously attributed to B. burgeri, are placed sister to B. axelmeyeri by molecular phylogenetic analysis. They differ by 1.9% DNA sequence divergence, and by a brown versus a red upper iris area, but are here tentatively assigned to B. axelmeyeri. This differentiation among mid-altitude amphibian species of Marojejy and Tsaratanana/Manongarivo may be indicative of a process of allopatric isolation among populations from these massifs.

A new sauropod dinosaur with prosauropod-like teeth from the Middle Jurassic of Madagascar

AbstractA dentary bone containing several teeth, from the Middle Jurassic (Bathonian) of northwestern Madagascar is described as the type of a new sauropod dinosaur taxon, Archaeodontosaurus descouensi, n.g., n.sp. This taxon is characterised by the unusual combination of a dentary with a deep anterior part, as in advanced sauropods, and teeth with large serrations and a convex lingual side, which resemble the teeth of prosauropods. A more common pattern in early sauropods is the combination of a low, prosauropod-like dentary and spoon-shaped, sauropod-like teeth. Although the condition in Archaeodontosaurus descouensi strongly suggests that basal sauropods had prosauropod-like teeth, what is known of the jaw and dentition in various early and middle Jurassic sauropods indicates mosaic evolution along different paths during the early diversification of the group. Archaeodontosaurus descouensi differs from Jurassic sauropod material from Madagascar, previously described as Bothriospondylus and Lapparentosaurus, which needs revision. It appears that at least two distinct sauropods, with different tooth morphologies, are present in the Middle Jurassic of Madagascar.

Parental care behavior in the monogamous, sexually dimorphic Madagascar paradise flycatcher: sex differences and the effect of brood size

AbstractI studied the parental care behavior of the Madagascar paradise flycatcher Terpsiphone mutata in northwestern Madagascar. I especially focused on feeding, brooding and vigilance behaviors. Feeding rate did not differ between males and females, but females spent more time at the nest than males. Females dedicated their time to brooding, while males perched on the nest and were vigilant. Both parents changed the feeding rate in relation to brood size, so the feeding rate per nestling was not different among nests of different brood size. Duration of brooding by females increased with decreasing brood size, suggesting that the Royama effect, the pattern of lower feeding rate per nestling in larger broods, did not apply in this study. Males spent more time on vigilance than females. Anti‐predator vigilance by males should be important for nestling survival given the high predation pressure typical of this population. In conclusion, males provide considerable parental care probably to minimize nestling starvation and to avoid nest predation. My results are not consistent with the general pattern of less parental effort by males in monogamous, sexually dimorphic species.

Fine-grained debris flows and extraordinary vertebrate burials in the Late Cretaceous of Madagascar

Vertebrate fossils are remarkably abundant and exceptionally well preserved within the Upper Cretaceous Maevarano Formation of northwestern Madagascar. The vast majority of these fossils, including all of the currently known bone beds, are entombed within deposits of fine-grained cohesive debris flows. These deposits are typically massive and are characterized by very poor sorting and a significant montmorillonite-dominated silt-clay (mud) fraction ranging from 17% to 46% by weight. Deposition is attributed to recurrent exceptional rainfall events that prompted erosion and flooded ancient channel belts with sediment-laden flows. These extraordinary burial events shielded vertebrate remains from destructive surface processes and also afforded protection for soft tissues. Taphonomic attributes of associated bone concentrations suggest that debris flows had limited transport potential and generally entombed subaerially exposed bone assemblages. The remarkable and recurrent association of bone beds and debris-flow deposits likely reflects marked seasonality in this Late Cretaceous terrestrial ecosystem, with prolonged dry spells prompting mortality and subsequent rains setting debris flows in motion.

Presence of a posterodorsal ridge in Jurassic to Recent larval shells of arcoidean bivalves

A posterodorsal notch is known from the larval shells (PII) of extant Ostreidae and Gryphaeidae. 1‐3 It results from a postanal ciliary tuft that deforms the shell edge and leaves a ridge-like growth track on the prodissoconch. 3 In fossil Ostreoidea this feature has been traced back into the Middle Jurassic, and was considered a probable autapomorphic character of the Ostreoidea. 4,5 The aim of this research note is, however, to document a posterodorsal ridge in some larval shells of Jurassic, Cretaceous, Eocene and Recent arcoid bivalves. All studied specimens were juveniles (� 3 mm in length), making determination of their taxonomic position below superfamily level beyond the scope of this study. The Recent material was collected in the lagoon and reef area of Foulpointe (also known as Mahavelona), 58 km north of Tamatave in northeastern Madagascar, from depths not greater than 5 m. The Eocene material was collected near Damery in the Paris Basin, France, and is of Lutetian age. 6 The Cretaceous material was collected in the vicinity of Ambatolafia in the Mahajanga Basin in northwestern Madagascar, and is of lower Albian age. 7 The Jurassic material was collected 3 km south of Zakaraha in southwestern Madagascar, and is of Bajocian age. 8 In all cases, sediment samples were taken and fractionated by sieving with mesh-sizes of 2.0, 1.0 and 0.5 mm. The Cretaceous and Jurassic samples were treated with a 5‐10% H2O2 solution using standard procedures prior to sieving. Specimens were mounted on stubs, sputter-coated with gold, and photos were taken with a Leo 1455VP scanning electron microscope. In all, 28 specimens belonging to seven species were examined (Table 1); in species E and G only right valves were available for study. The material is deposited in the palaeontological collection of the Museum fur Naturkunde in Berlin, Germany.

マダガスカル北西部におけるブラウンキツネザルの行動圏，日周活動，採食様式

マダガスカル北西部におけるブラウンキツネザルの行動圏，日周活動，採食様式

Utilisation of wild growing yams as supplementary nutrition and its impact on the dry forest ecosystem in north-western Madagascar

Wild growing yams (Dioscorea spp.) are an important supplementary food in Madagascar, especially during periods of rice shortage in the rainy season. Yams grow in dry forests and there is a particularly high occurrence of yam tubers in recently burned, open secondary forest formations. The study found that the uncontrolled harvest of yams can contribute to the degradation of dry forests due to the high quantity of wild yams harvested by the local population and the widespread practice of intentionally burning forests to increase yams production.

First definitive record of Mesozoic lizards from Madagascar

ABSTRACT We report here the first unequivocal record of a pre-Late Pleistocene lizard from the island of Madagascar, based on a nearly complete lower jaw, elements of both the pectoral and pelvic girdles, several vertebrae and ribs, and numerous osteoderms of what is presumed to be a single individual. The specimen, recovered from the Upper Cretaceous (Maastrichtian) Anembalemba Member, Maevarano Formation, Mahajanga Basin, northwestern Madagascar, is identified as a scincoid scincomorph and, more specifically, a new genus and species of ?Cordylidae (Cordyliformes), based on a combination of gnathic, dental, and postcranial characters. The new taxon is the first identifiable lizard from the Late Cretaceous of the African continent (sensu lato). If the new taxon is correctly attributed to the Cordylidae, it constitutes a significant temporal and geographic range extension for the clade since cordylids have no definite representatives in the fossil record and extant forms are restricted to the sub-Saharan portion of mainland Africa. This new record also indicates that cordylids, after their occurrence in the Maastrichtian, became extinct on Madagascar, leaving only zonosaurine Gerrhosauridae as extant representatives of Cordyliformes on the island. Owing to limited knowledge concerning the time of divergence for cordylids and gerrhosaurids relative to the tectonic separation of Africa and Madagascar, and in light of the paucity of Mesozoic lizard fossils in general, and from Gondwana in particular, the discovery of the new taxon in the Late Cretaceous of Madagascar does little to otherwise constrain scenarios concerning the biogeographic history of early cordyliforms. Finally, we document here the observation that lizards appear to have been much less speciose than snakes in Late Cretaceous faunas of Gondwana, whereas the reverse is true in Laurasia. Lizards do not appear to become common in Gondwana until the Early Tertiary.

Diet and nutrition in wild mongoose lemurs (Eulemur mongoz) and their implications for the evolution of female dominance and small group size in lemurs.

Data collected on the feeding behavior, food intake, and chemical analyses of plant foods were used to document seasonal variation in diet and nutrition in Eulemur mongoz in northwestern Madagascar. E. mongoz conforms to the general Eulemur dietary pattern, with a predominantly frugivorous diet supplemented mainly by leaves, flowers, and nectar. Phytochemical analysis revealed high water contents in all the main plant foods; mature fruit and flowers contained the most water-soluble carbohydrates; immature leaves were richest in protein and essential amino acids; the limiting amino acids in all plant foods were methionine and cystine; ash (mineral) content was highest in petioles and mature leaves; crude lipid content was highest in seeds; and crude fiber content was indistinguishable between immature and mature fruit and leaves. High-fiber foods were eaten during both seasons; the wet season diet was dominated by high-energy foods (mature fruit, nectar, and seeds), while the dry season diet contained foods high in energy (mature fruit and flowers) and high in protein (immature leaves) and minerals (mature leaves and petioles). However, nutrient intake did not vary between seasons, implying that nutrient requirements are met throughout the year. These results suggest we draw more conservative conclusions when interpreting dietary variability in the absence of chemical analysis, and also draw into question the idea that nutritional stress is a factor in the timing of reproduction in lemurs and, by extension, is linked to the prevalence of female dominance and small group size in lemurs.

Social organization of the golden brown mouse lemur (Microcebus ravelobensis).

Our study provides the first data on the social organization of the golden brown mouse lemur, a nocturnal primate discovered in northwestern Madagascar in 1994. The study was carried out in two 6-month field periods during the dry season, covering time before and during the mating season. The spatial and temporal distributions of the sexes in the population were investigated by mark/recapture and radiotelemetry. Focal observations and the determination of sleeping associations provided further insights into the sociality of this solitary forager. High intra- and intersexual home-range overlaps occurred throughout the study. In general, individuals of both sexes had spatial access to more than one conspecific of the same and the opposite sex. We found no indication for spatial monopolization of females by certain males. These results suggest a dispersed multimale/multifemale system with a promiscuous mating pattern. Individuals showed temporal stability in their home range locations and interacted regularly with conspecifics. Five sleeping groups were identified during the study period: one female group and four mixed-sex groups. Even though sleeping sites were changed frequently, sleeping-group compositions remained stable over time. Thermoregulatory constraints are the most likely explanation for sleeping-group composition with members of both sexes in this species. Mixed-sex sleeping groups can be described as the basic social unit within this dispersed multimale/multifemale society.

A molecular approach to comparative phylogeography of extant Malagasy lemurs.

The lemurs of Madagascar provide an excellent model for exploring evolutionary diversification. This study investigates genetic divergence among most extant lemur taxa in relation to potential geographical boundaries to gene flow. For this purpose, approximately 2,400 bp of mitochondrial DNA (part of the COIII gene; ND3, ND4L, and ND4 genes; and five tRNAs) were sequenced in a total of 131 lemurs from 5 families, 12 genera, 25 species, and 18 subspecies to reconstruct phylogenetic relationships among them. The comprehensive range of taxa makes this a particularly suitable molecular data set to examine lemur evolution. Those data clearly reveal that the Betsiboka River acts as an isolating barrier between populations of lemurs in north-western Madagascar. The Tsiribihina River similarly serves as a barrier to gene flow between northern and southern populations of lemurs in central western Madagascar, whereas the Mahavavy River does not seem to lead to genetic isolation of lemur populations. Several discrepancies among molecular data, current taxonomy, and geographic distribution along the western coast emerged. Examination of geographical distribution of the taxa concerned in comparison with distribution boundaries of other lemur taxa in that region yielded explanations for these inconsistencies. Eulemur fulvus and Eulemur mongoz are the only lemur taxa that also occur outside Madagascar, on the Comoro Islands. Genetic data show no significant differentiation between Malagasy and Comorian populations of these species, supporting the interpretation that both were introduced only recently to the Comoro Islands.

Species-specific usage of sleeping sites in two sympatric mouse lemur species (Microcebus murinus and M. ravelobensis) in northwestern Madagascar.

We investigated the sleeping site ecology of two sympatric mouse lemur species (Microcebus murinus and M. ravelobensis) in northwestern Madagascar during the second half of the dry season with respect to the type, quality, and usage pattern of the sleeping sites, as well as to social sleeping habits and response to potential threats. The type and quality of the sleeping sites differed between the two species. M. murinus used protected wooden shelters (tree holes) more frequently than M. ravelobensis, and M. ravelobensis used a broader variety of less protected sites (e.g., branches, lianas, and leaves) than M. murinus. Whereas male M. murinus usually slept alone, and female M. murinus mostly slept in groups, both sexes of M. ravelobensis slept in mixed-sex sleeping groups. M. murinus relied on crypsis in their sleeping sites, whereas M. ravelobensis regularly showed a flight response to the approach of an observer. This behavioral difference could indicate an adaptation to a higher predation risk in less protected sleeping sites. Whereas female M. murinus showed a high site fidelity, male M. murinus and both sexes of M. ravelobensis frequently changed their sleeping sites, which may also be interpreted as an antipredator strategy. The results are discussed with respect to three possible ecological explanations: interspecies competition, restricted resource availability, and niche differentiation. The latter is the most likely explanation for these interspecific differences.

Side-Necked Turtle Lower Jaws (Podocnemididae, Bothremydidae) from the Late Cretaceous Maevarano Formation of Madagascar

Two lower jaws from the upper part (early Maastrichtian) of the late Cretaceous Maevarano Formation in the Mahajanga Basin, northwestern Madagascar, are identified as belonging to side-necked turtles (Pleurodira). A nearly complete lower jaw is identified as cf. Erymnochelys because of its close resemblance to the living Malagasy Erymnochelys madagascariensis. Both uniquely possess the combination of a posteriorly directed processus retroarticularis and a nearly identical triturating surface that is narrow anteriorly with a horizontal labial ridge and a dorsally rising lingual ridge. A second specimen, consisting of an incomplete symphyseal region, is questionably identified as Bothremydidae on the basis of a thick wedge-shaped symphysis with partial or complete pits on the rami. The cf. Erymnochelys specimen is the oldest record of Erymnochelys or a taxon very similar to it, and it indicates the persistence of a Mesozoic element in the extant Malagasy turtle fauna. The possible bothremydid jaw suggests a more cosmopolitan element now extinct.

Relationship Between Microhabitat Structure and Distribution of Mouse Lemurs ( Microcebus spp. ) in Northwestern Madagascar

Understanding processes affecting the distribution and abundance of organisms is a central issue in ecology and conservation biology. In northwestern Madagascar, we found an uneven distribution pattern of the golden-brown mouse lemur (Microcebus ravelobensis) and the grey mouse lemur (M. murinus). In one area (JBA) the two species lived sympatrically, whereas in another forest area (JBB) Microcebus ravelobensis occurred exclusively. To investigate whether differences in forest structure may explain this uneven distribution, we conducted a microhabitat analysis and related it to specific distribution. In JBA the habitat of Microcebus ravelobensis was characterized by a higher percentage of trees with many lianas and a higher cover of the herb layer, whereas that of M. murinus had a higher number of trees with a diameter at breast height (DBH) >10 cm. The comparison of the forest structure of the microhabitats of the two species between JBA and JBB revealed further differences. The cover of the overstory, the percentage of trees without lianas and the number of larger trees (DBH >10 cm) among the microhabitats were higher for Microcebus murinus in JBA than for M. ravelobensis in JBB whereas the microhabitats of M. ravelobensis at the two sites did not differ concerning these vegetation structures. Differences between the two species coincide with those of resources important for survival. Our results indicate the importance of microhabitat analyses for the understanding of distribution patterns of species and for successful conservation planning.

Hunting of protected animals in the Parc National d'Ankarafantsika, north-western Madagascar

Bones were obtained from the temporary camp of raffia palm fibre harvesters in the Parc National d'Ankarafantsika in north-western Madagascar. Based on the context of their deposition, knife-cut marks, and burn marks these animals were consumed for food. The minimum number of individuals (MNI) of wild animals represented in the sample was 49, and included turtles (MNI = 5), birds (MNI = 4), tenrecs (MNI = 4), Carnivora (MNI = 2), lemurs (MNI = 32), and bush pigs (MNI = 2). The majority of these animals are protected by Malagasy law and are endemic to the island.