Presentation in Dortmund about Madagascar

Presentation in Dortmund about Madagascar

by Alex Negro Reiseberichte Live lectures

Roland Zobel, a long-time member of the DGHT Dortmund City Group and self-confessed day gecko lover, will give a lecture full of pictures about a trip to the north of Madagascar on 07 April 2023 in Dortmund. There is much to discover in the north of the world’s second-largest island state, not only chameleons.

Roland Zobel Expedition Northern Madagascar
DGHT City group Dortmund
Restaurant “Olympia – Zur alten Post”
Im alten Dorf 2
59192 Bergkamen – Weddinghofen
Start of presentation 07.30 p.m.

Photo: Collage by Roland Zobel

Spines of tree- and ground-dwelling chameleons

Spines of tree- and ground-dwelling chameleons

by Alex Negro Tiermedizin Science

Various anatomical adaptations of the spine between ground and tree dwellers are known from mammals, especially primates. In some cases, the different vertebrae are even associated with certain movement patterns and bodily functions. In a comparative study, two scientists from New York (USA) have now investigated how the spine of ground- and tree-dwelling chameleons differs.

They measured the already existing CT scans on Morphosource.org of a total of 28 chameleons of different species. Brookesia perarmata, Brookesia superciliaris, Brookesia thieli, Palleon nasus, Rhampholeon platyceps, Rhampholeon spectrum, Rieppeleon brevicaudatus and Rieppeleon kerstenii were classified as ground dwellers. Archaius tigris, Bradypodion melanocephalum, Bradypodion pumilum, Bradypodion thamnobates, Calumma amber, Calumma brevicorne, Calumma parsonii, Chamaeleo calyptratus, Chamaeleo gracilis, hamaeleo zeylanicus, Furcifer lateralis, Furcifer pardalis, Furcifer verrucosus, Kinyongia carpenteri, Kinyongia tavetana, Kinyongia xenorhina, Nadzikambia mlanjensis, Trioceros feae, Trioceros jacksonii and Trioceros quadricornis were considered arboreal. The vertebrae were counted and the width of the lamina, length, width, height of the vertebral body, and the height of the spinous process and transverse processes on each vertebra were measured. In addition, the so-called prezygapophysial angle was determined. This is the angle of the intervertebral joint, i.e. the contact surfaces between the individual vertebrae. The measurements of ground and tree dwellers were compared and statistically evaluated. Only the vertebral column of the trunk was considered, the caudal vertebral column was left out.

First of all, the results showed that ground-dwelling chameleons generally have fewer trunk vertebrae (15 to 19) than tree-dwelling chameleons (18 to 23). The trunk spine of almost all species could be divided into the already known three areas: Cervical spine and anterior and posterior dorsal spine. A thoracic and lumbar spine as in mammals is generally not distinguished in chameleons because of the continuous ribs. Five chameleon species had four regions instead of three: they had an anterior and a posterior cervical spine, the anterior one consisting of only two vertebrae with rib processes. Six chameleon species had two additional lumbar vertebrae and one species had three transitional vertebrae in the region between the cervical and dorsal spine. In Kinyongia carpenteri, a total of five regions could be distinguished in the trunk spine: The chameleon had anterior and posterior cervical vertebrae as well as anterior and posterior dorsal vertebrae and two additional lumbar vertebrae. Brookesia perarmata was also a special case: the trunk spine of this chameleon consisted of only two regions and at the same time the smallest number of vertebrae of all species studied.

The greatest differences between ground and tree-dwelling chameleons were found in the prezygapophyseal angle (PZA) and the height of the spinous process. The intervertebral joint surfaces in the anterior dorsal vertebrae of tree-dwelling chameleons were clearly more dorsoventrally oriented and smaller than in ground-dwelling species. Several tree-dwellers showed a PZA of less than 90°. In tree-dwelling chameleons, the largest spinous processes were located at the transition from the cervical to the dorsal spine. Among the ground-dwelling species, the spinous processes were similar only in Palleon nasus. In ground-dwelling chameleons, the appearance of the spinous process varied greatly. Rieppeleon, for example, showed narrow, backward-sloping spinous processes, while the spinous processes in Brookesia were more like a kind of bone bridge than a process. Archaius tigris was an exception: The spinous processes in this chameleon hardly differed along the entire spine.

The authors conclude from the results that the anatomy of the different vertebrae is strongly related to the chameleons’ way of life and different locomotion. The intervertebral joint surfaces in tree-dwelling chameleons are probably important for climbing by supporting the function of the shoulder girdle. Reduced mobility in the mediolateral plane provides greater trunk stiffness, which facilitates climbing in arboreal dwellers. Stiffening of the axial skeleton (skull, trunk spine and thorax) is also known from tree-dwelling mammals. The larger spinous processes in larger chameleons could facilitate shoulder girdle rotation and muscle movement, resulting in increased stride length, better head support, and thus possibly easier feeding.

Morphological and functional regionalization of trunk vertebrae as an adaption for arboreal locomotion in chameleons
Julia Molnar, Akinobu Watanabe
Royal Society Open Science 10, 2023: 221509
DOI: 10.1098/rsos.221509

Illustration: Spines of different chameleon species

Long-term study on sperm collection in chameleons

Long-term study on sperm collection in chameleons

by Alex Negro Tiermedizin Science

Assisted reproduction has become increasingly common in the conservation of extremely rare animals such as the Spix’s macaw or northern white rhinoceros in recent years. In reptiles, on the other hand, there have only been a few studies on assisted reproduction, and only a few on chameleons in particular. Scientists from the USA have now conducted a study on male Veiled and Panther Chameleons (Chamaeleo calyptratus and Furcifer pardalis).

At Louisiana State University, 16 males of each species were kept under standardised conditions for over a year. The panther chameleons were purchased from a US breeder, the Yemen chameleons from a dealer who had taken them from the introduced wild chameleon population in Florida. All males were kept individually in ZooMed screen cages, equipped with automatic sprinklers and artificial plants. Temperatures were around 28-29°C during the day with spots to seek higher values. 12 h UV-B irradiation per day was offered. They were fed with crickets and zophobas.

Before the start of the study, all 32 chameleons were clinically examined and parasites were treated. Only after a month of acclimatisation did the actual study begin. During the study year, all chameleons were put under anaesthesia twice a month. Each time, blood was taken from the ventral tail vein or the jugular vein to determine the testosterone concentration. Ultrasound was used to measure the size of the testicles. In addition, each time an attempt was made to obtain sperm by electroejaculation. Electroejaculation involved inserting a small metal probe into the cleaned cloaca. Each chameleon was then treated up to three times in succession with up to 15 electric shocks of 0.1/0.2/0.3 mAs. The semen collection experiments were stopped as soon as the animal ejaculated. The sperm collected was preserved and examined for ejaculate volume, presence of sperm, sperm motility, concentration, and morphology.

The results suggest that Veiled Chameleons follow a so-called prenuptial reproductive strategy under constant husbandry conditions. The testosterone concentration in the blood already increased before the sperm volume of the males had reached its maximum. The months of May, April, and June brought the best sperm volumes, the most sperm was produced by electroejaculations in the third attempt. Testicle sizes also varied throughout the year, with the largest measurements from August to December.

Panther chameleons, on the other hand, seem to follow a postnuptial reproductive strategy. In them, most sperm could only be obtained well after the highest point of testosterone concentration. The electroejaculations worked best in March, April, May and June. Much more often than in Yemen chameleons, electroejaculation in panther chameleons worked already in the first attempt. The size of the testicles also varied throughout the year, but most were largest in the months mentioned above. Together with the factors mentioned above, the volume of ejaculate, sperm concentration, sperm motility and sperm morphology also changed during the year.

The authors recommend that electroejaculation in chameleons should generally only be performed under anaesthesia. The success rate for spermatozoa in the two highest cases was 82 and 88%, which is similar to the success in other reptiles during their reproductive season. The mortality rate among the 32 animals was only 0.12% over the whole year. One panther chameleon died after 10 months during the 20th anaesthesia, after death kidney damage was detected. From the low mortality rate, the authors conclude that electroejaculation rather does not play a role in the development of kidney disease, as was suspected in other studies. However, an examination of the blood for kidney values was not carried out on any of the surviving chameleons after the study. It also remains unclear what role the lack of imitation of rainy and dry seasons during the year plays for both species and their reproductive cycle.

Characterizing the annual reproductive cycles of captive male veiled chameleons (Chamaeleo calyptratus) and panther chameleons (Furcifer pardalis)
Sean M. Perry, Sarah R. Camlic, Ian Konsker, Michael Lierz, Mark A. Mitchell
Journal of Herpetological Medicine and Surgery 33 (1), 2023, pp. 45-60
DOI: 10.5818/JHMS-D-22-00037

Presentation in Hamburg about Namibia

Presentation in Hamburg about Namibia

by Alex Negro Reiseberichte Live lectures

The first chairman of the DGHT Landesverband Hamburg will give a lecture full of pictures about a journey to Namibia and western South Africa on 31 March 2023 in Hamburg. The travel goes from Cape Town to the Etosha National Park. Namibia, also called the “Land of Red Silence”, is one of the most fascinating and multifaceted countries on earth. Stops on Rüdiger’s journey included Namaqualand, which welcomed him in glorious blossom, several Namibian mountain ranges, the Namib around Swakopmund with a great reptile tour and a drive through the Welwitschia area, as well as the dune areas near Sossusvlei and the Fish River Canyon. Besides the large mammals of Etosha National Park, Rüdiger’s main focus on this breathtaking trip was, of course, the reptiles – and there were also a few chameleons to see. A firework for nature lovers!

Rüdiger Schlepper Namibia – In 22 days through the Southwest of Africa
DGHT Landesverband Hamburg
Vereinsgaststätte “Am Sportplatzring”
Sportplatzring 47
22527 Hamburg
Presentation starts at 8 pm

Photo: Flower carpet in Namaqualand, photographed by Rüdiger Schlepper

Our conference programme for May 2023

Our conference programme for May 2023

by Alex Negro AG Interna

After we were able to publish a preview of the conference programme in December last year, we now have the final conference programme. This year’s conference will take place from 05 to 07 May 2023 in the tranquil town of Boppard am Rhein. As experience shows that the weekends in Boppard are booked up quickly, we recommend that you look for a hotel or guesthouse soon. Our programme has become a nice mixture of keeping reports, general terraristics and travel reports. Friday is the traditional day for arrival and a pleasant dinner in the local restaurants.

Saturday starts with a classic husbandry and breeding report. Jean-Dominique Dufraine has been keeping Rieppeleon brevicaudatus and Archaius tigris for several years. He talks about his experiences in breeding, but also in the everyday keeping of the two species. Afterwards, Thorsten Negro will take us on a search for Parson’s Chameleons in their natural habitat in Madagascar.

In the afternoon, Oliver Witte will give us an exciting insight into law, legislation and terrarium keeping – don’t worry, it won’t be as dry as it sounds, but very interesting for chameleon keepers. As a highlight, the physicist Sarina Wunderlich from www.lichtimterrarium.de has also agreed to join us. LEDs are becoming increasingly popular in terrarium keeping, not least because they can save a lot of electricity. Sarina will show us the advantages and risks of LEDs and discuss the latest development, UV LEDs. After these two presentations, we have planned plenty of time for discussion and questions, because there will certainly be plenty to talk about. At the end of Saturday, Rayana Vuillemain will introduce us to the Association Caméléon Centre Conservation (Switzerland) – this is the only presentation in English.

Sunday will be another colourful day: Lars Dwinger will report on a Madagascar trip to the southern highlands and the central east of the island. He travelled between carpet chameleons and rice fields as well as in the rainforest of Ranomafana, where he met a variety of small and large chameleons. Markus Grimm will conclude with an overview of Chamaeleo chamaeleon in its natural habitat in Europe as well as keeping and breeding them in terrariums.

We are very much looking forward to a nice meeting and many chameleon friends!

Chamaeleo namaquensis offspring in the AG

Chamaeleo namaquensis offspring in the AG

by Alex Negro AG Interna Nachzuchten

A great breeding success was achieved by AG-member and former AG-speaker Timo Weiß this week: His Chamaeleo namaquensis offspring hatched successfully. Congratulations!

The Namaqua chameleon is one of the few existing chameleons that actually occur in real deserts. It lives in the wild in Namibia, South Africa and Angola on the African continent. Unlike many other chameleon species, it inhabits mainly the ground and low shrubs.

Photo: One-day-old juvenile on the hand of the successful keeper

Comparisons on limbs of Hadramaut agama and Veiled Chameleon

Comparisons on limbs of Hadramaut agama and Veiled Chameleon

by Alex Negro Science

A Yemeni biologist at Al Saeed University recently took measurements on two different reptile species to compare their forelimbs and hindlimbs structurally and functionally. Both the Hadramaut Agama (Acantocercus adramitanus) and the Veiled Chameleon (Chamaeleo calyptratus) occur in the same habitats in Yemen, but they inhabit different microhabitats and move differently. While the agama lives mainly on the ground and in low bushes, the Veiled Chameleon is a pure tree dweller.

For the study, 10 specimens of each species were taken from the wild in Taiz. The head-torso length of the agamas ranged from 52 to 125 mm, and that of the chameleons from 90 to 200 mm. The animals were killed and the limbs were removed, stained, and then measured.

The structure of the limbs was basically the same in both species, but the hands and feet were clearly different. The Hadramaut Agama has five carpal bones, whereas, in the Veiled Chameleon, the distal carpal bones 2,3, and 4 are fused. Both species lack distal tarsal bones 2 and 5. The Veiled Chameleon lacks the sesamoid ossicles, which are variable in the agama. As expected, the long bones of the Veiled Chameleons were almost equally long on the forelimbs and hindlimbs, while in the agamas the forelimbs were significantly shorter than the hindlimbs. Overall, all long tubular bones were longer in the chameleon than in the Hadramaut Agama.

The skeletal characteristics of limb of two endemic lizard species (Acantocercus adramitanus and Chamaeleo calyptratus) in Yemen
Yaser H.A. Obady
Al-Saeed University Journal of Humanities and Applied Sciences 06 (1) 2023: pp. 188-210
DOI: 10.17161/randa.v30i1.18614

New distribution data on Chamaeleo zeylanicus

New distribution data on Chamaeleo zeylanicus

by Alex Negro Verbreitung Science

A biologist from India has published findings of the Indian Chameleon (Chamaeleo zeylanicus) that narrow down the distribution of the species more precisely. The Aravalli Mountains are located about 150 km west of the Indian capital New Delhi in northwest India. It runs for 670 km in a south-westerly direction, passing through three different states: Haryana, Rajasthan, and Gujarat. Until now, the Indian chameleon was thought to occur in the south and centre of Rajasthan, but was not common in the north, east, or west. So far, no findings had been documented from Haryana at all.

The biologist describes six observations of the Indian Chameleon between 2015 and 2022, during which Chamaeleo zeylanicus was seen four times in the Sariska Tiger Reserve and once each at Manesar and Damdama lakes, at altitudes between 223 and 476 m asl. The former is in northern Rajasthan, the two lakes not far from it in southern Haryana. The forest of the site in the Sariska Tiger Reserve is dominated by Indian lungwort (Adhatoda vasica), prairie mugwort (Parthenium integrifolium) and mesquite tree (Prosopis juliflora). The chameleons found in Haryana were found on roadsides with carira (Capparis decidua) and mesquite trees.

New distributional records of Asian Chameleons (Chamaeleo zeylanicus Laurenti 1768), from the Northern Aravali Hill range, India
Debaprasad Sengupta
Reptiles & Amphibians 30 (1), 2023: pp. 1-2
DOI: 10.17161/randa.v30i1.18614