Ichnotropis microlepidota Marx, 1956

Ichnotropis microlepidota Marx, 1956 View in CoL

Figs 4 View Figure 4 , 5 View Figure 5 , 6 View Figure 6 , Table 4 View Table 4 , Suppl. material 1: tables S 1, S 7

Holotype.

FMNH 74285 About FMNH , adult male, collected at the foot of Mount Moco , Huambo Province, Angola, on 19 September 1954 by Gerd Heinrich.

Paratypes.

FMNH 74283–84 , adult females, with the same collecting information as the holotype ; FMNH 74286–7 , adult males, with the same collecting information as the holotype .

New additional material.

MHNCUP -REP 0983 , adult male, collected at Mount Moco , Huambo Province, Angola (- 12.4554, 15.1632), 2300 m a. s. l., on 18 October 2020 by Pedro Vaz Pinto GoogleMaps .

Additional referred material.

A juvenile specimen collected at Mount Moco , Huambo Province, Angola, 1500–1900 m a. s. l., in March 1934 by Karl Jordan ( Parker 1936) .

Updated description.

Measurements and meristic data are summarized in Suppl. material 1: table S 1. Ichnotropis microlepidota is a medium-sized lizard species (maximum SVL = 61.00 mm, mean 56.8 ± 4.8). 4 upper labials anteriorly to the subocular (mostly 2–3 posteriorly to the subocular), 7–8 (mostly 7) lower labials, and 5 pairs of chin shields, from which the first three pairs are in contact. Rostral with slight insertion between nasals. Single rhomboid frontonasal scale, slightly wider than longer. Undivided anterior loreal scale, which is smaller than the larger posterior loreal. Prefrontal scales longer than wider and in contact with supraoculars. Single row of scales between posterior loreal and anterior supraocular scales. Four supraciliaries on each side, which can be in contact or not with the anterior supraoculars. Three supraoculars, with the first (anterior one) being the largest, followed by a slightly smaller second supraocular and a third one, which is the smallest. Eight rows of temporal scales between temporal shield and upper labials. Temporal shields half the length of parietals. Parietals twice as long than broad. Frontal scale 2–3 times longer than wide. Semicircular-shaped occipital scales slightly extending past the parietal scales. Head shields heavily striated. Dorsal scalation is composed of small, heavily keeled, rounded scales slightly elongated towards the back. High number of scales around the midbody (43–50, mean 47.8 ± 2.8). Middorsal scales slightly larger than dorsal scales and lack keeling towards the venter. Ventral pholidosis with large hexagonal scales that lack keeling. 23–27 ventral plates in the longitudinal section and between 8–10 in the transverse section. Tail scalation is formed by elongated and keeled scales pointing towards the tail tip and disposed in rings (Fig. 5 View Figure 5 ). Subdigital lamellae 16–19. Femoral pores 9–12 per side.

The cranium presents on its overall a rounded shape on its lateral and dorsal view (Fig. 6 A, B View Figure 6 ). Frontal and parietal bones fused and separated by the fronto-parietal suture (Fig. 6 A View Figure 6 ). Both bones are heavily striated in their dorsal view. Pineal foramen present in the medial section of the parietal bone. Postorbital bones prominent, in tight contact with the postocular, frontal, parietal, and squamosal bones. Supratemporal bone present, located as a splinter of a bone between the squamosal and the posterolateral process of the parietal (Fig. 6 E View Figure 6 ). Nasal bones paired (Fig. 6 D View Figure 6 ). Lacrimal bone present and unfused with the maxilla (Fig. 6 B View Figure 6 ). A large jugal bone present in contact with the lacrimal bone, ectopterygoid, and postorbital bone. Braincase elements fused. Otostapes unperforated. The sclerotic rings comprise 14 ossicles with similar shape and size. Vomer bones paired (Fig. 6 C View Figure 6 ). A robust lower jaw with a high and prominent coronoid bone (Fig. 6 F – I View Figure 6 ). Compound bone and surangular bones fused. Splenial bone large in contact with compound bone, coronoid, and dentary. Nine premaxillary tooth loci, 20 maxillary tooth loci, and 22–23 dentary tooth loci.

Comparative diagnosis.

This species can be differentiated from I. bivittata by having higher number of scales around the midbody (43–50 vs. 32–39 in I. bivittata ) and a lower number of subdigital lamellae under the fourth toe (16–19 vs. 18–20 in I. bivittata ). Furthermore, I. bivittata presents narrowly yellow-spaced spots above the front limbs, while I. microlepidota lacks this dorsolateral spotting. Furthermore, I. microlepidota presents anterior suboculars, which can be in contact or not with the supraciliaries, while in I. bivittata , they are always separated. Moreover, it differs from the capensis group by having a more rounded and shorter snout, prefrontals in contact with the anterior supraoculars, a higher number of scales around the midbody (43–50 vs. 30–41 in I. capensis and 34–41 in I. aff. capensis ), a lower number of subdigital lamellae under the fourth toe (16–19 vs. 18–26 in I. capensis and 19–24 in I. aff. capensis ), and for lacking a lateral orange band in adult males, which is highly conspicuous in adult males from the capensis group. It also differs from I. aff. grandiceps in the number of lamellae under the fourth toe (16–19 vs. 19–24 in I. aff. grandiceps ) and for the same orange band in adult males as in the capensis and bivittata groups. In addition, I. microlepidota can be differentiated from I. bivittata based on a few osteological characters as follows: broader cranium dorsoventrally, with a taller dorsoventral profile, a shorter and more robust jugal bone, a more downfacing and laterally compressed premaxilla, and longitudinally compressed maxilla and dentary bones in I. microlepidota versus a narrower and shorter cranial profile in I. bivittata . The skull of I. bivittata presents an overall rounded shape in its lateral and dorsal view. Parietal and frontal bones separated by the fronto-parietal suture, and both with low striation in their dorsal view. The pineal foramen situated in the medial to anterior section of the parietal. Elongated jugal bones in their lateral view, in contact with lacrimal bone, ectopterygoid, and the postorbital bone. Otostapes unperforated. The sclerotic rings comprise 14 ossicles with similar shape and size. Nasal and vomer bones paired. An elongated lower jaw formed by coronoid, dentary, splenial, and fused compound bones, all of them in contact. Nine premaxillary tooth loci, 20 maxillary tooth loci, and 23 dentary tooth loci. (Fig. 4 View Figure 4 ).

Coloration in life

(Fig. 5 G – H View Figure 5 ). The dorsal pattern consists of a light brown dorsal band that reaches from behind the head to the posterior limbs, surrounded by two discontinuous bands consisting of black blotches. The pattern on the lateral side of the body consists of two light cream to yellow bands from ear opening height extending towards the back. Between them, a row of consecutive pairs of white ocelli surrounded by external black sections. Under the lower lateral band, another row of continuous single ocelli. The head is brown on top, sprinkled with black markings on most of the scales. Mouth opening is surrounded by a black coloration, which turns white to the upper part of the upper labials and to the lower part of the lower labials. The first row of chin shields is fully black, and rows 2–5 are half white (towards the outside) and half black. The gular coloration consists of a light orange color, some black scales, and two conspicuous bright yellow-orange speckles under the posterior end of both lower jaws. Ventral coloration is immaculate white.

Variation.

Meristic and morphometric data are summarized in Suppl. material 1: table S 1. The new individual of I. microlepidota (MHNCUP - REP 0983) has a smaller snout-vent length when compared to the type series (Suppl. material 1: table S 1). Sexual dimorphism appears in the head height (HH), higher in males than in females (6.2 ± 0.5 vs. 5.3 ± 0), in the head length (HL), longer in males (12.1 ± 1 vs. 11.5 ± 0.2), in the scales around the midbody, higher in females (49–50 vs. 43–49), and in the number of ventral scales in transversal view, higher in males (8–10 vs. 8). In addition, the newly collected material presents a proportionally larger HH (Suppl. material 1: table S 1) when compared to the type series, probably a consequence of the decomposition stage of the type series when they were found.

Distribution and habitat.

Ichnotropis microlepidota represents a micro-endemic Angolan species only known to occur at Mount Moco, Huambo Province (Fig. 8 View Figure 8 ). The type series (holotype and paratypes) were found in the crop of a goshawk, which was collected at the base of Mount Moco. However, the locality may lack precision given that the bird could have captured the lizard elsewhere. The habitats at Mount Moco include open montane and fire-prone grasslands with scattered bushes and trees, rocky outcrops, and remnants of Afromontane forest in deep gullies (Fig. 7 View Figure 7 ). The montane grasslands start at around 1800 m a. s. l. but are most prominent above 2100 m a. s. l. and are formed by a thick layer of grass and small bushes as well as many rocks underneath. The grass species present in those grasslands are Festuca spp. , Monocymbium ceresiiforme , Themeda triandra , Tristachya inamoena , Tristachya bequertii , Hyparrhenia andongensis , and Hyparrhenia quarrei , among others ( Mills et al. 2011). Shrub cover usually includes species such as Cliffortia spp. , Erica spp. , Philippia benguelensis , Protea trichophylla , Stoebe vulgaris , and Xerophyta spp. , although the last ones mainly appear in rocky outcrops ( Mills et al. 2011).

Natural history.

Ichnotropis microlepidota is a ground-dwelling lizard with diurnal habits. The specimen reported here (MHNCUP - REP 0983) was found during the day on top of an exposed small rock in open montane grassland habitat, with thick vegetation cover. Few reptile species were observed in the area, but at least one Viperidae species has been previously recorded in the region and same habitat, namely the endemic Bitis heraldica , which may prey on Ichnotropis microlepidota . Other reptile species recorded nearby but associated with rocky or wetland habitat included Crotaphopeltis hotamboeia , Cordylus momboloensis , Trachylepis albopunctata , Trachylepis sulcata , Panaspis cabindae , Agama cf. schacki , and Afroedura wulfhaackei .

Conservation status.

The species is listed as Data Deficient (DD) on the IUCN Red List ( Ceríaco et al. 2020 c). This is a consequence of the lack of information about the distribution of this species and the specific threats that menace the sites where it occurs. Even with the collection of this new individual of I. microlepidota (MHNCUP - REP 0983), this information is still incomplete, and therefore, it is likely that this species will remain listed as Data Deficient (DD).