Philochortus zolii, Scortecci, 1934, Scortecci, 1934

in den Bosch, Herman A. J., 2020, Observations on the Egyptian Grass - loving Lizard, Philochortus zolii (Lacertidae), Pod @ rcis 11 (2), pp. 29-39 : 31-34

ECOLOGY

Philochortus zolii inhabits semi-deserts near oases with some clumps of grass and sparse bushes like Tamarix and sparse stands of Alhagi graecorum , commonly known as manna tree. It will also use the leftovers of nearby attempts to grain-growing. Various other smaller and less prominent plants can be found in the habitat. Several patches seem to be devoid of vegetation, at least at the time when the lizards were collected.

HABITS

We spent three days near Wadi Natrun, also taking stock of other possible Philochortus habitats there. On the last day, together with Sherif Baha el Din, we found several specimens. Six lizards (presumably four more or less adult specimens, and two subadults) were caught. One adult female went with Sherif who released her in the garden of his new home, which was reminiscent of the original habitat, hoping that she would be the foundress of a new population.

The five other animals were transferred to Leiden; Sherif thought a breeding program would be a good idea since their habitat disappears rapidly because of poor recent agricultural practice. Naturally, I was interested in learning more about their reproductive behaviour so a partnership was begun.

BEHAVIOUR

When caught with a sling, the animals quickly spiralled their tail around the string and/or catching stick (in this case a thin part of a fishing rod) in a way very much reminiscent of a picture in ARNOLD' s (1989) paper on various African lacertids where fig. 12 showed a Podarcis muralis curling its tail in a less extreme manner. Remarkably enough, all the animals we spotted, were at the base of the tufts of grass ( fig. 2 ), not ín it as you would expect from this behavioural pattern and their general morphology. Further, on a flat surface (=quarantine vivarium), they performed a peculiar walk: it looks as if they put their heels first on the surface, then the foot sole and toes follow and with the legs held widely apart (cf. ARNOLD, 1998).

There does not seem to occur a seasonal colour change during the year, although older specimens seemed to show less contrast dorsally and the tail turns to a beige.

In the vivarium the spotlights were switched on from 9:30-15:00h in the summer months. The Philochortus emerged, and became active, about an hour later, after basking. They disappeared usually 1-2 hrs. later. Only in the beginning of March the lizards remained active longer, up to 15:00h, but then disappeared even when the sun still shone in their vivarium as it did usually during less cloudy days, in the afternoon. Later in the summer season they were sometimes active up to 17 o'clock. This is in contrast to the majority of Lacerta s.l., Podarcis , Psammodromus and other Western Palearctic lacertids I have cared for over the years. While basking they intermittingly opened their mouth for just a few seconds. A way of cooling down the head while the rest of the body still 'needs' some heat? Since there was no indication of any sickness, shortness of breath was ruled out. Towards the end of November most specimens hardly showed themselves anymore, they began to appear more regularly near the end of February, but only in March/April did activity increase somewhat. This may well be related to the more sunny conditions outside in The Netherlands. In February they appeared more regularly, but mainly between 10-11h, in March until 15:00h. In Nov-Dec only one specimen (female?) was clearly visible, although another lizard could sometimes be discerned under the dead grass where the vivarium was closest to the radiator in the living room. This practice remained somewhat the same over the years. When exactly they prefer to drink was unclear until one early morning an animal crept out from under a stone and immediately headed for the drinking nap. One may interpret this as logical since in the desert some water in the form of dew may only be available in the early morning.

It is common for lacertids in my vivaria to jump up to the gauze top covering and hang on belly-up. However, the Philochortus seemed to prefer to have their back up and their belly towards the floor ( fig. 7 ). They can even run quickly without any awkward movements that way, potentially because their long legs easily spread out (see Discussion and photos). Additionally, they showed a peculiar kind of walk in 'normal' locomotion, with their heels touching the substrate first and with a rolling movement the rest of the foot is put down. The whole gait appeared rather spread out, which certainly seems fitting when moving in the grass.

At the end of July 2008 I observed for the first time three 2-3” long bites in the tail of another specimen. To me this seemed like an introduction to courtship as I experienced such in many other lacertid species. However, no follow-up occurred and they parted without any other actions. On 5 and 12 July 2009 I saw two very 'emaciated' specimens with flattened bellies, presumably females and consequently searched the whole terrarium but did not find any eggs.

Early morning July 10, 2009 I noticed a small hole in the vivarium substrate very near a piece of bark, which next appeared to be closed by early afternoon and during the night. One of the smaller specimens was responsible for this first hole. The closing occurred from the inside by pushing substrate outside with the tip of the snout and the front legs. A larger specimen seemed to have taken up residence under a large stone. There the potential opening and closing was hard to observe because the vivarium is in the corner of the room near the window. In the field I did not see this opening and closing, but when chased did see them using these initially inconspicuous burrows as an escape route ( fig. 8 ).

Although they walked around after basking for a while in the vivarium, it is difficult to say the Philochortus really often actively hunted for food. In contrast to many lacertids, they seemed to be fond of mealworm pupae, but then again they may cross these repeatedly without noticing that as a food item and only when given by tweezers (often the same pupa!) and held in front of them, was it grabbed and eaten. I rarely saw them running after any of the insects or spiders presented. They surely must do so in the wild? The lizards dug enthusiastically, even so much that smaller stones became displaced. They often remained subterraneous for longer periods, with a predilection for warmer spots in their housing. In December and January the P. zolii showed themselves even more rarely and I switched off the light sometimes for several days as in their natural habitat temperatures may then fall well below 10°C and some kind of hibernation could be likely. In that period most lizards remained hidden, although on close observation one or two were spotted among the dried grass tussocks.

Even after having kept them for several years, none of the specimens had an even slightly swollen tail-base, often seen in male lizards, and none of the femoral pores exuded the waxy rods so characteristic of reproductive males. Only in one or two, the largest lizards, the diameter of the femoral pores grew a bit larger.

Suddenly a first death happened 24 May 2010, probably a female. Later that year, and into 2011 all the animals died. After consultation and autopsy and discussion by veterinarians at the University of Utrecht, it became clear that the cause was a spoiled vitamin D 3 preparation. Unbeknownst to me this had been stored in the deep freeze by the apothecary who prepared the vitamin supplement. This was extremely disappointing. Possibly the effect of the absence of the vitamin took hold relatively fast in Philochortus as one can presume desert lizards normally receive a large dose of UV which helps in forming vitamin D 3 under natural circumstances.

THREATS

Apart from the obvious disastrous human influence ( fig. 5 ), it is to be feared that the many botched attempts at agriculture in Wadi Natrun will seriously hamper the survival of the only known Egyptian population of P. zolii . This lizard no doubt is prey to some birds, and to the night-active snake Spalerosophis diadema found in the area, that is especially fond of lizards. I am, however, unsure if the snake captures them in their burrows ( fig. 8 ), or out in the open during dawn and dusk. From my own experience S. diadema is rarely if ever active in daytime during the warmer months.

Figures

Figure 2. The habitat with clumps of Halfa grass near Wadi Natrun.

Figure 5. Wadi Natrun is definitely not an undisturbed area.

Figure 7. How Philochortus zolii walks along the with mosquito gauze covered top of the vivarium, with its back upward.

Figure 8. Holes in the desert soil dug by Philochortus zolii.