A molecular phylogeny of ichthyophiid caecilians (Amphibia: Gymnophiona: Ichthyophiidae): out of India or out of South East Asia?

Recent molecular phylogenetic studies indicate that the rafting Indian plate harboured several isolated vertebrate lineages between ca. 130 and 56 Myr ago that dispersed and diversified 'out of India' following accretion with Eurasia. A single family of the amphibian order Gymnophiona, the Ichthyophiidae, presently occurs on the Indian plate and across much of South East Asia. Ichthyophiid phylogeny is investigated in order to test competing out of India and out of South East Asia hypotheses for their distribution. Partial sequences of mitochondrial 12S and 16S rRNA and cytochrome b genes for 20 ichthyophiids and proximate outgroups were assembled. Parsimony, maximum-likelihood and distance analyses all recover optimum trees in which uraeotyphlids plus Ichthyophis cf. malabarensis are the sister taxa to all other Ichthyophis, among which the South East Asian taxa are monophyletic. Tree topology and branch lengths indicate that the Indian lineages are more basal and older, and thus are more consistent with the hypothesis that ichthyophiids dispersed from the Indian subcontinent into South East Asia. The estimated relationships also support monophyly of Sri Lankan Ichthyophis, and non-monophyly of striped and unstriped Ichthyophis species groups. Mitochondrial DNA sequences provide evidence that should assist current problematic areas of caecilian taxonomy.

[A new actograph operating by capacitance sensing]. / Ein neuer kapazitiv arbeitender Aktograph.

Capacitance sensing devices are useful for ecological and ethological studies (Zucker et al., 1968). If the location and activity of small animals (e.g. newts) is to be recorded, problems arise due to the very small changes in capacitance that must be detected reliably. By using a special bridge circuit (Fig. 2) an extremely sensitive detector can be constructed. With the output voltage and frequency of the RF-generator kept constant, the RF-current is determined only by the capacitance of the two sensors C1 and C2. This current is rectified by the transistors T1 and T2 and the difference is detected by a Schmitt trigger. Outside influences that affect both sensors in the same way will thus be eliminated, resulting in excellent long-time stability and sensitivity of the device.The sensors simply consist of copper foils, about 1 cm apart, glued onto an insulating, flat surface. A glass with the animal is placed on these sesors and no further connection is necessary. The change in capacitance is generated by the animals building a capacitance bridge over the space between the foils. By a suitable arrangement of foils and spaces (Fig. 3), any desired information can be obtained concerning activity, time of entering and leaving the hiding place, etc.Newts and salamanders need a damp atmosphere. It was found that a moist paper on the bottom of the container will increase the sensitivity if its degree of humidity be kept constant.

The fine structure of the lateral-line organs of larval Ichthyophis (Amphibia: Gymnophiona).

Light and electron microscopic observations of the lateral-line organs of larval Ichthyophis kohtaoensis confirmed earlier reports of the occurrence of two different types of lateral-line organs. One type, the ampullary organ, possesses 15-26 egg-shaped sensory cells. Each sensory cell extends a single kinocilium surrounded by a few microvilli into the ampullary lumen. This is in contrast to the ampullary organs of urodele amphibians that contain only microvilli. The second type of organ, the ordinary neuromast, has 15-24 pear-shaped sensory cells arranged in two to three rows. Each sensory cell shows a kinocilium that is asymmetrically placed with respect to both a basal plate and approximately 60 stereovilli. The sensory cells of ampullary organs are always separated by supporting cells; those of neuromasts are occasionally in contact with one another. Numerous (neuromasts) or few (ampullary organs) mantle cells separate the organs from the epidermal cells. Only afferent synapses are found in the ampullary organs whereas vesicle-filled fibers together with afferent nerve terminals are found in neuromasts. Both organs contain similarly sized presynaptic spheres adjacent to the afferent fibers. It is suggested that the neuromasts have a mechanoreceptive function, whereas the ampullary organs have an electroreceptive one.