Lygodactylus tsavoensis, Malonza & Bauer & Granthon & Williams & Wojnowski, 2019

Malonza, Patrick K., Bauer, Aaron M., Granthon, Carolina, Williams, Dean A. & Wojnowski, David, 2019, A new species of gecko of the genus Lygodactylus (Sauria: Gekkonidae) from southeastern Kenya, Zootaxa 4609 (2), pp. 308-320 : 313-317

Lygodactylus tsavoensis sp. nov.

Tsavo Dwarf Gecko

Holotype: NMK L1384 /2, (adult male, Figs. 3 A–E), KMC Ranch—Bachuma , Tsavo area, Taita-Taveta County, Kenya (03 o 40.775’ S, 0 38 o 58.692’ E, 423 m), collected by Patrick K. Malonza, Joash O. Nyamache and Beryl A. Bwong, 14 May 2013.

Paratypes: NMK L1384 /1, adult male, same data as holotype ; NMK L1380 /4 (adult male) , NMK L1380 /5 (adult female) , LMD Ranch—Bachuma , Tsavo area, Taita-Taveta County, Kenya (03 o 39.659’ S, 0 38 o 51.713’ E, 458 m), collected by Patrick K. Malonza, Joash O. Nyamache and Felista K. Kilunda, 22 May 2013 .

Etymology. The specific name tsavoensis refers to the Tsavo Conservation Area, the type locality of the new species.

Unfortunately, the name of this new taxon, along with a description and two photographs, were inadvertently published by Spawls et al. (2018), who apparently thought that our description had already been published. In reality, on the date of publication of Spawls et al. (2018) — 25 January 2018 according to the publisher’s website (https:// bloomsbury.com/uk/field-guide-to-east-african-reptiles-9781472935618/)—the corresponding author of this paper had not yet received reviewers’ comments, which were provided by the editor on 23 February 2018. This new species would have unintentionally been validly described in a popular field guide but for Articles 16.1 and 16.4 of the International Code of Zoological Nomenclature ( International Commission on Zoological Nomenclature 1999) which respectively state “Every new name published after 1999, including new replacement names (nomina nova), must be explicitly indicated as intentionally new” and “Every new specific and subspecific name published after 1999, except a new replacement name (a nomen novem), for which the name-bearing type of the nominal taxon it denotes is fixed automatically, must be accompanied in the original publication (16.4.1) by the explicit fixation of a holotype, or syntypes, for the nominal taxon, and (16.4.2) where the holotype or syntypes are extant specimens, by a statement of intent that they will be (or are) deposited in a collection and a statement indicating the name and location of that collection.”

Diagnosis: Lygodactylus tsavoensis sp. nov. is assignable to the L. picturatus species group on the basis of having a large, undivided mental scale followed by three postmentals and subcaudal scales with the median row strongly transversely enlarged. There are five adhesive lamellae beneath the fourth toe ( Fig. 3E ) and four subcaudal adhesive lamellae. Seven precloacal pores are present in males ( Fig. 3D ).

The body is grayish-blue (although this may change based on ambient conditions and physiological state; see Coloration in life); the top of head is cream with a dark pattern that forms a Y-shaped chevron joining the orbits ( Fig. 3A, B ) and continuing posteriorly as two dark stripes which merge at the tail base, breaking up into one dark, irregular stripe along the tail. A dark streak from the snout extends through the eye and ends posterior to the shoulders where it breaks up into irregular blotches on the flanks and on the dorsal surface of limbs and sides of the tail ( Fig. 3A ). The throat in males is black ( Fig. 3C ) or has white chevrons on a black background and a white chin spot, more or less similar to L. wojnowskii females or L. keniensis males and females.

Lygodactylus tsavoensis sp. nov. differs in its small body size (males: SVL 30.7-32.8 mm; female 26.2 mm) from its close relatives L. wojnowskii (males 35–38 mm SVL, females 30–38 mm) and L. mombasicus (males 37–39 mm, females 34–35 mm). Lygodactylus keniensis is closer in size to the new species ( Table 1 ), and shares with it a similar number of precloacal pores, seven in males of L. tsavoensis sp. nov. versus 7–8 in L. keniensis .

Most diagnostic differences distinguishing L. tsavoensis sp. nov. from other members of the L. picturatus group are associated with color pattern ( Fig. 4 ). The pale, Y-shaped mark or chevron on the top of the head in the new species continues posteriorly as a pale vertebral stripe up to the tail base. A similar head pattern characterizes L. wojnwoskii , but extends only to the level of the shoulders. Although L. keniensis shares with L. tsavoensis sp. nov. the Y-shaped mark or chevron on top of head this does not continue as a pale or cream vertebral stripe. Lygodac- tylus mombasicus lacks the Y-shaped chevron and exhibits dark chain-like marks or stripes instead. Lygodactylus kimhowelli (SVL ~ 36 mm) has a pattern similar to L. mombasicus except for the head pattern, which has regular dark stripes and, like some L. mombasicus , has dark stripes that extend posteriorly up to tail base. Similar to L. mombasicus there is no sexual dichromatism in dorsal pattern in adult L. tsavoensis sp. nov. However, the young of L. tsavoensis sp. nov. is greyish with a striped, golden brown head and golden tail, whereas in L. mombasicus the juvenile color is similar to that of adults. In L. picturatus (SVL males 38–39 mm; females 35–36 mm) the head to the shoulders of males is vivid yellow and striped whereas in females the region is greyish and striped. The young of L. pucturatus are uniformly greyish like those of Lygodactylus tsavoensis sp. nov., but lack the golden brown tail of the latter taxon. Lygodactylus scorteccii (37 mm) have a yellow or cream striped head and a broken chevron mark on the crown as in some L. keniensis but this does not form a pale stripe that continues posteriorly up to tail base as in L. tsavoensis sp. nov and, likewise, it lacks the dark dorsal stripes of the latter species or, if present, they are faded. Lygodactylus manni (SVL 36 mm) has a brown rather than black stripe through the eyes that breaks posteriorly and does not extend to the shoulders as in L. tsavoensis sp. nov. and it has an irregular chevron and scattered speckles on the cream head, with little contrast. Morphological comparisons with other Lygodactylus picturatus group species are summarized in Table 1 and a list of comparative material examined is provided in the Appendix.

Description of holotype. NMK L1384/2: Adult male; SVL: 32.8 mm; TrunkL: 14.6 mm; CrusL: 5.5 mm; TaiIL: 35.8 mm; TaiIW: 3.6 mm; HeadL: 10.9 mm; HeadW: 6.4 mm; HeadH: 4.7 mm; EarL: 0.9 mm; ForeaL: 4.6 mm; OrbD: 1.4 mm; NarEye: 3.7 mm; SnEye: 5.5 mm; EyeEar: 2.4 mm; Internar: 1.6 mm; Interorb: 5.3 mm. Build small; head narrow and distinct from neck. Snout short and rounded, distance from snout tip to anterior border of eye slightly greater than the anterior interorbital distance, greater than distance between eye and ear opening. Eye very small, bead-like, with brown iris, ear opening small and rounded.

Body slightly elongate (TrunkL/SVL = 0.4). Snout covered with heterogeneous flattened granular scales, medium-sized on crown of head and small laterally above eye, becoming larger on the middle and anterior portions of snout, largest in loreal region ( Fig. 3B ). Scales on the snout larger than those on the occiput, which are, in turn, much larger than the small dorsal granules ( Fig. 3A ). Canthus rostralis prominent and rounded. Rostral pentagonal, wider than high. Nostril oval and directed slightly posteriorly, bordered by rostral, first supralabial, supranasal, and two postnasals; supranasals separated by a single small internasal granule, three internasals. Mental heptagonal and undivided, followed by three large postmentals and five postpostmentals ( Fig. 3C ). Scales behind postmentals enlarged, decreasing in size towards base of throat, then increasing in size on chest and belly. Supralabials 8/8; infralabials 6/6. Gulars imbricate, 24 between posteriormost infralabials. Dorsal granular scales roughly homogeneous, slightly larger on ventrolateral portions of trunk. Limbs well developed but short, pentadactyl, 1 st digit greatly reduced and lacking claw. Distal portions of remaining digits expanded, bearing claw. Four pairs of lamellae under fourth finger; 8 enlarged subdigital scales occur proximally to manual lamellae; five pairs of lamellae beneath fourth toe ( Fig. 3E ). Granular scales on dorsal surface of limbs roughly homogeneous and similar size to those on trunk; scales on ventral surface of thighs subhexagonal, subimbricate, and same size as those on trunk; ventral scales more than twice as large as dorsals, smooth, and imbricate, scales on ventral surface of arms subhexagonal, subimbricate, and smaller in size than those on trunk. Precloacal pores seven, arranged in a chevron roughly six scale rows anterior to cloaca ( Fig. 3D ). Tail shape cylindrical, caudal scales smooth, dorsally semi-flattened, imbricate, largely homogeneous; subcaudal scales large, flattened, subhexagonal, subimbricate, and with the median row strongly enlarged transversely. An adhesive set of setae-bearing scales are borne on the underside of the original tail tip. Complete original tail slightly longer than body length (TailL/SVL ratio = 1.01).

Coloration in ethanol. Trunk dorsum grayish. Head region with a white chevron between the orbits, continuing posteriorly as a vertebral stripe bordered by dark stripes; anterior to the pale chevron and to the orbits there is a pale pair of crescentic markings that may fuse in the midline posteriorly and that anteriorly enclose a roughly circular dark patch. A pale streak or blob extends anteriorly to the rostral scale from the anterior margin of this dark patch, as is seen in many other L. picturatus group species ( Fig. 3B ); a dark streak through the eye extends posteriorly to the shoulders; throat black. Tail grayish with longitudinal blotches along its entire length. Venter of body and limbs whitish; palms and soles cream. Throat pattern of Lygodactylus tsavoensis sp. nov. is dark in the majority of males ( Fig. 3C ), whereas that of females and a few males has chevrons and a white chin spot.

Coloration in life. Dorsum generally grayish to bluish ( Fig.4A ). The median belly is yellow, a feature present in several picturatus group species, and the throat is conspicuously black or bears black chevrons. Cream stripes on the head form a Y-shaped chevron mark that is continuous with a pale vertebral stripe extending the entire length of the body dorsum, this pale stripe is bordered by two dark stripes that join at the tail base. The boldness of these black and white markings varies and may be faded in some specimens. The pale markings anterior to the chevron and orbits are yellow in life. The flanks bear irregular blotches. The tail is grey or bluish and has median dark marks or chevrons. The dark dorsal stripes may fade or disappear due to external stimuli such as a change in temperature or light, or to physical disturbances which provoke changes in the animal’s physiological state. In bright, sunny conditions the species exhibits a bright and well-marked color pattern, whereas in cold weather and/or at high elevations, as in the Chyulu Hills, individuals are dull. There is no well-marked difference in sexes in terms of color. Juveniles are greyish brown dorsally with a golden brown tail.

Paratype variation. Paratypes are similar to the holotype in all meristic features, including the number of lamellae under the fingers and toes ( Table 2 ). Adult female NMK L1380/5 has the same color as the males, but the throat has three white chevrons that converge to a white chin spot.

Natural history. Lygodactylus tsavoensis sp. nov. is a diurnal arboreal species, active most of the day. The species occurs mainly in arid Acacia-Commiphora-Combtretum vegetation. It prefers mostly shorter trees and shrubs of a variety of species depending on the local circumstances. Dead fallen tree branches are also utilized. They are less frequently found on large trunks of trees such as Acacia , Adansonia, Ficus , and Commiphora . Around human habitations they are common on fences hedges of Euphorbia and exotic and even invasive plants. It may occur in pairs or small groups and many can often be found on the same tree. It was observed to co-exist with L. picturatus (in lowland areas of Kasigau, e.g., Bungule and Jora, Kambanga Ranch near Kilibasi Hill-Kwale, Mwatate-Taita and on the Kitobo forest edge-Taveta) and with L. laterimaculatus at the LMD Bachuma Ranch. In the Kibwezi area and Chyulu Hills it should co-exist with L. scheffleri but this species has not been recorded for many decades. In the extreme parts of Kitui and the mid-Tana River and Garissa it may likely co-exist with L. scorteccii . In all these sites Hemidactylus platycephalus Peters as well as the tree skink Trachylepis planifrons (Peters) are also syntopic with this species.

Distribution, habitat and conservation status: Lygodactylus tsavoensis sp. nov. has a continuous distribution in the southern, eastern and south-eastern arid lands of Kenya. Its elevational range is from approximately 400 m to about 1100 m above sea level, except in hill ranges within the Tsavo plains, like the Chyulu Hills, where it can reach approximately 1450 m. Records ( Fig. 1 ) include Tsavo East and West National Parks and surrounding wildlife and livestock ranches, and areas with similar ecological characteristics in the region such as Chyulu Hills National Park (02°32.736’ S, 037°50.909’ E, 1408 m; 02°33.610’ S, 037°53.326’ E, 1200 m; 02°29.973’ S, 0 37 o 56.130’ E, 1023 m); Kibwezi Forest, Makueni (02 o 24.731’ S, 0 37 o 57.283’ E, 933 m; 02°27.935’ S, 037°54.797’ E, 1013 m); Bungule, Mt. Kasigau (03°50.409’ S, 038°40.048’ E, 612 m); Kitobo Forest-Taveta (03°26.837’ S, 037°37.230’E, 716 m); Ngurumani (01°47.277’ S, 036°03.251’ E, 771 m); Magadi-Shompole area (02.07781° S, 036.17377°, 620 m); Namanga-Maili Tisa area (02°29.058’ S, 036°49.0896 E, 1324 m); Elangata-Wuas area-Kajiado (01 o 53.243’ S, 0 36 o 35.562’ E, 1320 m); and Maliku in Kitui (01 o 36.066’ S, 0 37 o 53.487’ E, 955 m). The species has also been photographed at Hunters Lodge-Kiboko Range Station-Makueni, Amboseli National Park-Kajiado, and Galana Ranch-Tana River/ Kilifi County, Lake Jipe-Tsavo West National Park. Due to its widespread distribution, as well as its ability to tolerate anthropogenic disturbance the species may be considered as Least Concern under IUCN criteria for conservation purposes.

Figures

FIGURE 1. Map of Kenya showing elevation and major localities mentioned in the text for the Lygodactylus tsavoensis sp. nov. Red circle indicates the type locality of Lygodactylus tsavoensis sp. nov. and light blue circles are other localities where this species has been recorded.

FIGURE 3. (A) Preserved holotype specimen of the Lygodactylus tsavoensis sp. nov. (NMK L1384/2); (B) Head dorsum and (C) throat, (D) cloacal region and tail base, (E), right hind foot. Scale for A in mm, scale bars for B–E = 1 mm. Yellowish cast in B–E partly an artifact of lighting conditions.

FIGURE 4. Life photos showing coloration of representative Lygodactylus picturatus group taxa. Photos by P.K. Malonza unless otherwise indicated. (A) Lygodactylus tsavoensis sp. nov., KMC Ranch-Bachuma Gate, Kenya. (B) L. wojnowskii, Kenyatta University, Nairobi, Kenya, photo by Washington Wachira. (C) Lygodactylus keniensis, Matthews Range, Samburu, Kenya. (D) Lygodactylus kimhowelli, captive (Tanzania), photo by D. Wojnowski. (E) Lygodactylus picturatus (male), Nguluku, Shimba Hills, Kenya. (F) Lygodactylus mombasicus (female), Mwandabara area, Shimba Hills, Kenya.

Tables

TABLE 1. Summary comparison of key morphological measurements and other characters among members of the Lygodactylus picturatus group from Kenya (*based on material collected subsequent to the type series, the female paratype is quite small and average size is closer to that of males, raising the average adult SVL).

Species/Character	Average adult
	SVL	Head markings	Dorsal pattern sexual dichromatism
L. tsavoensis	32 mm*	clear chevron on cream crown	dark stripes present	Absent
L. keniensis	35 mm	irregular chevron or stripes	Stripes absent	Absent
L. wojnowskii	36 mm	clear chevron on cream crown	Stripes absent or not clear	Absent
L. mombasicus	37 mm	chain-like black blotches on
		white crown	Stipes occasionally present Absent
L. picturatus	37 mm	dark stripes on yellow head	dark stripes absent	Present
L. scorteccii	35 mm	chevron and stripes on yellow
		or cream	Stripes absent or fade	Absent
L. manni	35 mm	Chevron/ irregular stripes	Stripes absent	Absent