Trioceros serratus (Mertens, 1922)

Ineich, Ivan, LeBreton, Matthew, Lhermitte-Vallarino, Nathaly, Abstract. - The, Laurent Chirio, Oku, Mount & Highlands, Bamenda, 2015, The reptiles of the summits of Mont Oku and the Bamenda Highlands, Cameroon *, Amphibian & Reptile Conservation (e 108) 9 (2), pp. 15-38 : 20-23

Trioceros serratus (Mertens, 1922) (101 specimens)

( Figs. 9–14)

Material: MNHN-RA 1997.3642 (male; Mt. Oku , Oku village, coll. CamHerp L. Chirio, May 1997) – MNHN-RA 1998.0415 (female; Mt. Oku , Lake Oku, elev. 2,200 m, coll. CamHerp L. Chirio, July 6, 1998) – MNHN-RA 1998.0416-0430 (15 specimens, Mt. Oku , elev. 2,000 -2,500 m, coll. CamHerp L. Chirio, June 25, 1998) – MNHN-RA 2005.2728-2732 (five specimens, Mt. Oku area , Anyajua village, above Bello, 6.236°N and 10.394°E, elev. 2,100 m, coll. CamHerp M. LeBreton and L. Chirio, April 19, 2000) – MNHN-RA 2005.2733-2734, 2005.2736 (three specimens, Awing village (Benjom), 5.867°N and 10.266°E, elev. 1,747 m, coll. CamHerp M. LeBreton and L. Chirio, December 14, 2002) – MNHN-RA 2005.2735 ( Awing village (Benjom) , 5.867°N and 10.266°E, elev. 1,747 m, coll. CamHerp M. LeBreton and L. Chirio, July 8, 2002 – MNHN-RA 2005.2737 ( Baba II village, 5.857°N and 10.102°E, elev. 1,772 m, coll. CamHerp M. LeBreton and L. Chirio, December 14, 2002) – MNHN-RA 2005.2738-2744 (seven specimens, Baba II village, 5.857°N and 10.102°E, elev. 1,772 m, coll. CamHerp M. LeBreton and L. Chirio, July 8, 2002 [MNHN-RA 2005.2739,.2741 and.2743: December 14, 2002]) – MNHN-RA 2005.2745 ( Bamboutos , Mt. Mekua, 5.688°N and 10.095°E, elev. 2,700 m, coll. CamHerp L. Chirio, March 30, 2000) – MNHN-RA 2005.2748 ( Bingo village , 6.166°N and 10.290°E, elev. 1,435 m, coll. CamHerp M. LeBreton and L. Chirio, December 14, 2002) – MNHN-RA 2005.2749-2752 (four specimens, Mt. Oku , Elak Oku village, 6.202°N and 10.505°E, elev. 2,000 m, coll. CamHerp M. LeBreton and L. Chirio, July 8, 2002) – MNHN-RA 2005.2755-2759 (five specimens, Mbiame , 6.190°N and 10.849°E, elev. 1,955 m, coll. CamHerp M. LeBreton and L. Chirio, July 8, 2002 [MNHN-RA 2005.2758-2759: December 14, 2002]) – MNHN-RA 2005.2760-2761 (two specimens, Mbockghas , elev. 2,092 m, coll. CamHerp M. LeBreton and L. Chirio, December 14, 2002) – MNHN-RA 2005.2762-2771 (10 specimens, Mboh village , 6.327°N and 10.348°E, elev. 1,900 m, coll. CamHerp M. LeBreton and L. Chirio, July 8, 2002) – MNHN-RA 2005.2774-2775, MNHN-RA 2005.2777, MNHN-RA 2005.3381 (four specimens, Mufe village , 6.30°N and 10.35°E, coll. CamHerp M. LeBreton and L. Chirio, July 8, 2002) – MNHN-RA 2005.2776, 2005.2778-2780 (four specimens, Njinkfuin , 6.187°N and 10.375°E, elev. 1,500 m, coll. CamHerp M. LeBreton and L. Chirio, April 19, 2000) - MNHN-RA 2005.2781-2787, 2005.2900 (five males and three females; Mt. Oku , Simonkuh, 6.234°N and 10.572°E, elev. 2,109 m, coll. CamHerp M. LeBreton and L. Chirio, July 8, 2002) – MNHN-RA 2005.2788 (male; Mt. Oku , Oku village, 10.505°E and 6.202°N, elev. 2,000 m, coll. CamHerp M. LeBreton and L. Chirio, April 19, 2000) – MNHN-RA 2005.2812-2815 (four specimens, Tefo village , 6.30°N and 10.37°E, coll. CamHerp M. LeBreton and L. Chirio, July 8, 2002) – MNHN-RA 2005.2816-2824 (nine specimens, Veko village , 6.139°N and 10.578°E, elev. 2,044 m, coll. CamHerp M. LeBreton and L. Chirio, December 14, 2002 [MNHN-RA 2005.2817,.2819-2824: coll. July 8, 2002]) – MNHN-RA 2005.2900 ( Mt. Oku , Simonkuh, 6.234°N and 10.572°E, elev. 2,109 m, coll. CamHerp M. LeBreton and L. Chirio, July 8, 2002) – MNHN-RA 2005.3382 ( Babadjou , 5.699°N and 10.187°E, elev. 1,580 m, coll. CamHerp L. Chirio, no date) – MNHN-RA 2005.3383 ( Mbiame , 6.190°N and 10.849°E, elev. 1,955 m, coll. CamHerp M. LeBreton and L. Chirio, July 8, 2002) - MNHN-RA 2007.0461-0464 (two males and two females; Mt. Oku area , around Elak Oku village, 6.244°N and 10.507°E, elev. 1,973 m, coll. I. Ineich and N. Lhermitte-Vallarino, May 6, 2007) – MNHN-RA 1 2007.1461 ( Mt. Oku , Oku village, elev. 2,000 m, coll. I. Ineich and N. Lhermitte-Vallarino, May 7, 2007) – MNHN-RA 2007.1462 ( Mt. Oku , Oku village, elev. 2,000 m, coll. I. Ineich and N. Lhermitte-Vallarino, May 8, 2007) – MNHN-RA 2007.1463- 1464, 2007.1472 (three specimens, Mt. Oku , Oku village, elev. 2,000 m, coll. I. Ineich and N. Lhermitte-Vallarino, May 8, 2007) – MNHN-RA 2007.1465 (male; Mt. Oku area , Lake Oku, 6.202°N and 10.461°E, elev. 2,272 m, coll. I. Ineich and N. Lhermitte-Vallarino, May 8, 2007) – MNHN-RA 2007.1494 (male, neotype of T. serratus ; Mt. Oku , on the side along the road from Anyajua to Belo, not far from Belo, coll. I. Ineich, May 9, 2007) .

Klaver and Böhme (1992) described the subspecies T. wiedersheimi perreti from Mt. Manengouba. Later molecular studies of Barej et al. (2010) highlighted the possible specific status of this taxon. This same study showed that the nominal subspecies T. w. wiedersheimi comprises two distinct genetic clades, separated geographically. Previously T. w. wiedersheimi was considered to occupy savanna and altitude grasslands from 1,400 to 2,450 m in Mts. Bamboutos, Mbulu Hills, Mt. Lefo, Mt. Mbam, Mt. Oku, and Mt. Tchabal Mbabo, and westwards into Nigeria at Mts. Gotel and Mambilla and the Obudu Plateaus. The original description of T. wiedersheimi was based on two syntypes, a female from Tchabal Mbabo and a subadult male from the BH. The female was designated as the lectotype of T. w. wiedersheimi by Klaver and Böhme (1992), thus restricting the type locality to Tchabal Mbabo. This restricted its distribution to the northern part of that previously accepted (Tchabal Mbabo and Tchabal Gangdaba). The southern populations (BH, Mt. Mbam and Mt. Oku) represent a distinct taxon that may also include the populations of the Koano, Mt. Lefo and Mbulu Hills, and Plateau of southern Nigeria, but this has to be verified. An available name, Chamaeleo serratus Mertens, 1922 , was revalidated to accommodate these southern populations as Trioceros serratus (Mertens, 1922) , although its namebearing type was unfortunately destroyed during the Second World War. A neotype was designated by Barej et al. (2010) in recent MNHN collections (MNHN-RA 2007.1494, Figs. 10, 11). Its type locality is thus well attached to the area just above the city of Belo on the western flank of Mt. Oku.

Trioceros serratus occupies high savannas of the BH, Mt. Mbam and Obudu Plateau ( Nigeria). Note, however, that the reports of Gotel Mountains in Nigeria should be attributed to T. wiedersheimi . In the BH region, the species is cited from Bafoussam (Bangwa), Big Babanki (= Kedjom Keku), the Bamileke region of Dschang, Kishong, Mezam (Bafout), and Tsch’a Bekom (Barej et al.

1 Note that specimens MNHN-RA 2007.461-464 reported by Barej et al. (2010) refers to MNHN-RA 2007.1461- 1464.

2010). Our study allows addition of the following locations in the BH: Awing (Benjom), Baba II, Bali Ngemba, Bingo, Mbiame, Mbockghas, Mboh, Mufe, Njinkfuin, Tefo, and Veko. It was reported from Bafut (elev. 1,200 m, 6.08°N and 10.10°E) by Joger (1982) as Chamaeleo wiedersheimi .

Gonwouo et al. (2006) consider the taxon (named T. w. wiedersheimi ) to occur from 1,500 m to 2,450 m altitude, often in sympatry with T. quadricornis gracilior on Bamboutos Mts. at Foto, Dschang, and Mts. Lefo, Mt. Oku, and Obudu Plateau in Nigeria, and 2,700 m in Mt. Mekua. Wild (1994) reported the species between 2,200 m and 2,500 m at Mt. Oku (Ijim Ridge). Tilbury (2010) cited the species from 2,600 m above sea level at Mt. Oku. Perch height average is 90 cm at Mt. Oku, the lowest value found for different stations of its range (over two m at Tchabal Mbabo). Wild (1994) reported a mean perch height of 53 cm at Mt. Oku and a maximum height of 157 cm. However, we collected the neotype of the species in a palm tree at three m height near the edge of a main road ( Fig. 11)! The low perch height observed in altitude at Mt. Oku could be attributed to the scarcity of livestock and predators that cause little disruption for chameleons, or to a still unknown interaction between climate and vegetation ( Fig. 12). The species tolerates some degree of habitat degradation and does not hesitate to venture into cultivated areas retaining some original vegetation. Yet it is a sensitive species, recently threatened by the exotic pet trade and especially the destruction of its habitat (culture, fires, deforestation). The population at Mt. Oku, however, is still abundant. The species is common around the village of Elak Oku, including gardens and plantations. This is the most abundant Cameroon mountain chameleon. The species occupies relatively open habitats but does not hesitate to venture into closed canopy forest. A minimum night temperature of 2.9 °C was recorded in its habitat at 2,500 m altitude in December 1993 ( Wild 1994). Trioceros serratus mostly occupies herbaceous and shrub layer below two m, while T. q. gracilior occupies bushy and shrub layers above one meter, which generates a syntopy area in the stratum located between one and two m ( Wild 1994). Habitat separation in syntopy should be possible through the important size differences between both taxa, probably preventing dietary overlap.

The systematics of this species complex is not satisfactory, despite the revision of Barej et al. (2010). In fact, besides the obvious differences in size and coloration, the lowland form (larger) collected near Belo also differs from the altitude form (smaller) of the summit of Mt. Oku by the number of small scales around the large granules on the flanks ( Figs. 13, 14). Also one of us (II) collected the neotype of T. serratus up in a palm tree and this form seems much more arboreal than the altitude Mt. Oku form. It is very unlikely that these two morphotypes belong to the same taxon and further studies are required.

Gekkonidae Gray, 1825