The rediscovery of Chamaeleo ruspolii (Reptilia: Chamaeleonidae) in Somaliland with notes on its taxonomy and life history

Petr Nečas, Mark Spicer & Tomáš Mazuch

Corresponding author: petr.necas@me.com 

Abstract

Chamaeleo ruspolii belongs to the least known chameleon species at all due to its restricted range in hardly accessible region in the Horn of Africa. Recently, evidence of their existence was secured almost a century after the last specimen was collected, Photos of life specimens are presented together with information on their biotope, and their taxonomic status as a separate species is discussed. 

Key words: Chameleons, Horn of Africa, taxonomy, life history, Chamaeleo ruspolii

Introduction

Since ancient times, the Horn of Africa and its inland region, Ogaden, have held a special place in human culture. This area is rich in natural resources, ranging from minerals to a high biodiversity, making it a speciation hotspot for many organisms (Flintan & al. 2013). Notable examples include Milkweed plants of the family Euphorbiaceae (Peirson & al. 2013) and lizards of the genera Hemidactylus (Gekkonidae) and Xenagama (Agamidae), many of which are endemic to this region (Spawls & al. 2023). The Horn of Africa was considered, at least in part, the ancient mystical land of Punt, from which, according to legends, Egyptian pharaohs sourced precious materials like ivory, myrrh, and frankincense. The Egyptian female pharaoh Hatshepsut (1507–1458 BC, the 5th Pharaoh of the 18th Egyptian Dynasty) famously led an expedition to this land, as depicted in the wall paintings of her tomb at Deir el-Bahari near Luxor, Egypt (Cooney 2015; Creasman 2014).

The region has been characterised by instability and conflict, and in particular wars over resources, independence, and identity. Access to this territory has historically been limited to convoys and well-organized, military-assisted expeditions (Olika 2002).

At the end of 19th century, Prince Eugenio Ruspoli (1866–1893), Italian aristocrat - explorer, ethnologist and naturalist, botanical and zoological collector, organized two expeditions to this territory. Eugenio Ruspoli was born in Țigănești, Romania, on 6th January 1866, as a son of the Italian Prince Emanuele Ruspoli of Poggio Suasa (1838–1899) and Greek Caterina Vogorides-Konaki (1831–1870). He was a member of the Royal Italian Geographic Society and donated his collections to the Regio Erbario e Museo Coloniale of Rome, later transferred to the tropical herbarium in Florence (FT). During his second expedition to north-east Africa (1892–1893) he was killed by an elephant on the 4th December 1893 while hunting in the territory of the Amara Burgi in present-day Somalia (Wikipedia 2025).

His natural history collections include botanical (POWO 2025) and entomological material, reptiles, birds and mammals (Beolens & al. 2011; Boulenger 1896a, 1896b; Kultzer 1960; Loveridge 1936; Salvadori 1896; Spawls & al. 2023). He is commemorated by a number of taxa, e.g.:

Plants:

• Cissus ruspolii Gilg (= Cayratia ruspolii (Gilg) Suess.),
• Ceropegia ruspoliana K.Schum., Thunbergia ruspolii Lindau,
• Ruspolia Lindau (5 species in tropical Africa, South Africa and Madagascar)
  

Animals:

• Sepidium ruspolii Kultzer, 1960 (Insecta: Tenebrionidae)
• Hemidactylus ruspolii Boulenger, 1896 (Reptilia: Gekkonidae)
• Prosymna ruspolii (Boulenger, 1896) (Reptilia: Colubridae)
• Tauraco ruspolii Salvadori, 1896 (Aves: Musophagidae)

In 1893, Boettger described, based on Ruspoli's collected material, a new species of chameleon and named it Chamaeleon ruspolii with the type locality given as: "Ogaden, Somaliland".

His description was very exact and clearly defined the diagnostic features, separating it morphologically from the similar Chamaeleo dilepis Leach, 1819:

Despite the clear morphological distinction and great geographical isolation, Parker (1945), rearranged it to Chamaeleo dilepis as its subspecies and this was followed by many later authors without change:

• Chamaeleon ruspolii BOETTGER 1893: 116
• Chamaeleo dilepis ruspolii — PARKER 1942: 79.
• Chamaeleo dilepis ruspolii — MERTENS 1966: 13
• Chamaeleo dilepis ruspolii — KLAVER & BÖHME 1997: 34
• Chamaeleo (Chamaeleo) ruspolii — NECAS 1999: 127
• Chamaeleo dilepis ruspolii — GLAW 2015
• Chamaeleo dilepis ruspolii — MAIN et al. 2018
• Chamaeleo dilepis dilepis — TILBURY 2018 ("form ruspolii" is not a taxonomical category— see below)
• Chamaeleo ruspolii — SPAWLS et al. 2023

Necas, already in 1999, proposed its elevation to specific status, which was then followed by Largen & Spawls (2006) and Spawls & al. (2023). Tilbury (2018) presented his concept of differentiation within the Chamaeleo dilepis species not respecting systematic categories and handled all the previously described taxa as "forms", which is a non-existing taxonomic category and this way he caused a taxonomic confusion putting Chamaeleo ruspolii de facto into the synonymy of Chamaeleo dilepis, which was hardly his intention.

From the original type series deposited in the Senckenberg Museum in Frankfurt am Main, only the Lectotype SMF 16300 is known and represented for more than a century the only evidence of the existence of this species. The types were collected by Prof. Carlo Keller during Eugenio Ruspoli's first expedition at unspecified locality in Ogaden. Additional 12 specimens were collected by in 1932 by Colonel R. H. R. Taylor on the Ethiopia/Somaliland boundary in Haud, British Somaliland (45°18' E, 8°34' N), 2900ft a.s.l. (884m), precisely between the villages of Candhodhexe in the east and Davegoriale in the west, c.70—185km west of Boodle in the Togdheer region of Somaliland or immediately adjacent Ethiopia (Spawls & al. 2023). They were deposited in the British Museum of Natural History, London. No-one has reported on its live appearance and no photograph in life has ever been published. 

Tilbury (2018) gives their distribution as Ethiopia, Somalia: Confined to the northern part of the Ogaden and Haud, not reaching the mountains or the coastal plain and refers to Parker (1942) and Lanza (1983, 1990).

Spawls & al. (2023) defines the habitat and distribution: it is a species of the Somali arid zone, in flat, open and dry Vachellia-Commiphora savanna with soft red sand soil, at altitudes of 875—1,090m. Collected only at nine precise and one imprecise locality in the Haud of southern Somaliland and eastern Ethiopia in the northern Ogaden. 

The New Evidence

In May 2024 one specimen of chameleon was found by a humanitarian mine clearance worker, called Abdilahi Jama, and kept aside for the second author so that it could be examined and photographed. It was a tiny juvenile.

The approximate location is near Khatumo village in Somaliland UTM 502439 958440 (58°7.68' N, 8°22.12' E) at 1,006 m a.s.l. (3301ft).

A second specimen was found in August 2024 at the same location. The second author commented on the circumstances of the discovery: "It is all thanks to Maxamed Xuseen Diiriye - he was sitting at our work site when this one walked in front of him! This one appeared in a minefield control point, and our supervisor brought it for me to see." Both animals were photographed and released.

The third autor reported his unsuccessful attempt to find the chameleon in the approximate neighbourhood: "The area is a rather dry Acacia woodland with bushy vegetation on orange laterite ground, but in the vicinity of small temporary riverbeds and occasional seasonal rainfall, falling into the month of May as a rule. The locals reported their occurrence during the rainfall and shortly after, then they said they disappear and are not to be found until the next rainy season. The most frequent encounters of the chameleons come from the farmland, where various crops are grown, quite frequently the Qat, Catha edulis (Celastraceae). It is a flowering plant native to higher elevations of East Africa and the Arabian Peninsula, known for its stimulant effects when chewed. Common names for khat include "jaad" in Somaliland, "chat" in Ethiopia, "qat" in Yemen, Saudi Arabia, Oman, and Djibouti, "miraa, muhulo, and muirungi" in Kenya, and "mairungi" in Tanzania. Although khat is a mild drug, regular chewing can have destructive effects on the human psyche and negatively impact the local economy (Cox & Rampes 2003). Ironically, khat plantations can play a positive role in erosion control and the preservation of original bushland biotopes, benefiting species such as chameleons (Kassa 2012). 

The appearance of the reported two living specimens is in absolute accordance with the original description (Boettger 1893) and the known preserved museum specimens from Frankfurt (SMF) and London (BMNH).

The head is large with a blunt snout and a low casque, only slightly raised posteriorly. The majority of the head surface is covered by large, plate-like scales. The occipital lobes are large and are in contact medially. The scales of the occipital lobes and surrounding temporal region are are round, large, plate-like or half-lentil-like. The cranial lateral crest abruptly ends half-way between the orbit and the top of the casque, the parietal crest very distinct with a single row of laterally compressed tubercles. The gular and ventral crests are well developed consisting of subconical tubercles slightly larger than surrounding scales. The body scales are subhomogeneous. Males possess prominent tarsal spurs. The maximum size is about 27cm. Colour of live specimens ranges from olive green to brownish grey, with orange interstitial chin skin and two white spots on the flanks: one longitudinal strike just above the shoulder and one posteriorly from him. Another whitish element is a more or less continuous band extending from the lips at the level of the eyeholes and continuing across axilla towards the inguinal region, where it abruptly ends; it might continue behind the hip joint as a white strike posterolaterally of the cloaca and reaching to the base of the tail. It is scattered with darker brown or blackish dots. The head crests are markedly orange or brownish, same the dorsal crest. The gular and ventral crests are whitish or same colour as surrounding skin.

Discussion

Socotra, which was part of the Arabian Plate, began to separate from the African Plate as the Red Sea and Gulf of Aden started to open. This rifting process continued through the Cretaceous and Paleogene periods, eventually leading to the complete detachment of Socotra from the Gondwanan plates (Macey & al. 2008).

According to the phylogenetic tree by Macey & al. (2008) Chamaeleo monachus from Socotra is the basal taxon to all the other species of the Chamaeleo chamaeleon species group; it originated by an early vicariant isolation of Socotran population from African, Mediterranean and Arabian populations, when Socotra detached from the other Gondwanan plates (Razzetti & al. 2011). Macey & al. (2008) however could not include material of Chamaeleo ruspolii to their studies. In their tree, Chamaeleo monachus from Socotra stays directly between the Arabian/Pakistani/Indian/Sri Lankan dispersal group (including Chamaeleo arabicus, calyptratus and zeylanicus) and Chamaeleo dilepis, sampled from Tanzania. It is well possible, Chamaeleo ruspolii represents a missing link between Chamaeleo monachus and Chamaeleo dilepis. At least geographically, it makes sense, due to the very limited relict refuges, the two species (Chamaeleo monachus and ruspolii) inhabit nowadays.

Chamaeleo ruspolii is morphologically similar to Chamaeleo dilepis, but it shows stable and significant morphological differences if compared to all other recognised forms of Chamaeleo dilepis, summarised in the Tab.1.: 

                                                    Tab 1: Morphological differences of  Chamaeleo ruspolii and Chamaeleo dilepis.

Following the recommendation of Nečas (1999) and the most recent stance of Spawls & al. (2023), the distinct morphology, smaller size, geographical position and isolation is a good base to consider finally Chamaeleo ruspolii as an alone-standing species, as was followed throughout this entire text.

Acknowledgements

We would like express our gratitude to Jama and Diiriye, the humanitarian mine clearance workers, for providing the two above mentioned living specimens of Chamaeleo ruspolii enabling the publishing of their first live photographs.

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Nečas, P., M. Spicer & T. Mazuch (2025): The rediscovery of Chamaeleo ruspolii (Reptilia: Chamaeleonidae) in Somaliland with notes on its taxonomy and life history. Archaius 2(1): 4

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