Lobulia sabini, Kraus, 2020

Kraus, Fred, 2020, A new species of Lobulia (Squamata: Scincidae) from Papua New Guinea, Zootaxa 4779 (2), pp. 201-214 : 205-211

Lobulia sabini , sp. nov.

Figures 1E, F , 2C , 3 B–D, Table 1

urn:lsid:zoobank.org:act:070C6D0A-7C9A-4912-A0CB-2ADDB2E633E2

Holotype. BPBM 16766 (field tag FK 7408), collected by F. Kraus at “Camp 4” on N side Mt. Simpson , 10.0364° S, 149.5749° E, 2480 m a.s.l., Milne Bay Province, Papua New Guinea, 16 February 2003.

Paratypes (n = 20). Papua New Guinea: Milne Bay Province: same locality as holotype ( BPBM 16765 , 16768 , 16770 , 16775 , 16777 , 16780 ) ; Mt. Simpson summit, 10.0362° S, 149.5677° E, 2740 m a.s.l. ( BPBM 16772 , 16779 ) ; “Camp 5” on N side Mt. Simpson , 10.0209° S, 149.5947° E, 1490 m a.s.l. ( BPBM 16781–83 ) ; Bunisi village , 10.0171° S, 149.6002° E, 1420 m a.s.l. ( BPBM 16761–64 ) ; Siyomu Village , 10.0105° S, 149.6014° E, 1200 m a.s.l. ( BPBM 16784–88 ) .

Diagnosis. A moderately sized species of Lobulia , adult SVL 49.5–60 mm; with a body having a rounded cross-section, distinct frontoparietals, two supralabials posterior to subocular, scales of temporal region not highly fragmented, single pair of chinshields in medial contact behind the postmental, no ear lobules, subdigital lamellae 17–21 under 4th toe, mid-body scale rows 26–32, paravertebral scales 50–63, mid-dorsum covered with rows of small dark-brown spots or speckles, top of tail base with 2–4 rows of small dark spots/speckles, dark-brown lateral stripe or field present, pale-bronze dorsolateral stripe present, light field on abdomen that lacks brown spotting 4–8 scales wide, and brown spotting under thighs and precloacal region.

Lobulia sabini sp. nov. differs from all other species of Lobulia in having only a single pair of enlarged chin shields in medial contact (vs. 2 or more in the other species) and from all these species except L. stellaris in lacking ear lobules. Lobulia sabini sp. nov. further differs from L. brongersmai in having distinct frontoparietals (vs. frontoparietals fused together in L. brongersmai ) and a rounded body in cross section (vs. flattened in L. brongersmai ); from L. alpina and L. subalpina in having two supralabials posterior to the subocular supralabial (vs. three in L. alpina and L. subalpina ), in having the last supralabial entire (vs. horizontally divided into two scales in L. alpina and L. subalpina ), and in having the scales of the temporal region not highly fragmented (vs. highly fragmented in L. alpina and L. subalpina ); from L. glacialis and L. stellaris in having the scales of the temporal region not highly fragmented (vs. somewhat fragmented in L. glacialis and L. stellaris ), in having 17–21 subdigital lamellae (vs. 12–16 in L. glacialis and 13–18 in L. stellaris ), 26–32 midbody scale rows (vs. 32–36 in L. glacialis and 33–38 in L. stellaris ), and 50–63 paravertebral scales (vs. 67–76 in L. glacialis and 66–81 in L. stellaris ).

Lobulia sabini sp. nov. is most similar in scalation to L. elegans and L. lobulus . Besides the single pair of chin shields in medial contact and the lack of ear lobules, it further differs from L. elegans in its smaller adult size (SVL = 49.5–60 mm vs. 59–66.5 mm in L. elegans ), rounded body (vs. flattened in L. elegans ), lower mean number of subdigital lamellae under 4th toe (mean = 19.2, range = 17–21, n = 31 vs. mean = 23.2, range = 22–25, n = 10 in L. elegans ), and in having the dark-brown mid-dorsal markings reduced to small spots or speckles (vs. two rows of large black checkers in L. elegans ), a pale bronze dorsolateral stripe (vs. absent in L. elegans ), a dark-brown lateral stripe or field (vs. absent in L. elegans ), top of tail base with 2–4 rows of small dark-brown spots/speckles (vs. one row of large blotches in L. elegans ), having brown spotting under thighs and precloacal region (vs. uniformly white in L. elegans ), and a narrow light field on abdomen without brown spotting (mean = 6.6 scales wide, range = 4–8, n = 21 vs. uniformly 10 scales wide in six L. elegans ). L. sabini sp. nov. further differs from L. lobulus in its lower number of mid-body scale rows (26–32 vs. 34–36 in L. lobulus ), brown mid-dorsum without two lines of conjoined dark-brown spots (vs. with in L. lobulus ), and having brown spotting under thighs and precloacal region (vs. uniformly white in L. lobulus ).

Description of Holotype. Rostral broad but shallow, wider (2.0 mm) than deep (1.3 mm), projecting moderately onto tip of snout, its suture with frontonasal straight; nasals approximately rectangular, widely separated, projecting approximately one-third of way onto dorsum of snout; nostril circular, centered within nasal; frontonasal large, with seven sides, extending laterally to dorsal level of nares, barely touching frontal, posterior margins shal- lowly concave; prefrontals moderate in size, narrowly separated, bordered below by two loreals; supraoculars four, anterior two contacting frontal, posterior three contacting frontoparietal; frontal kite shaped; one pair of frontoparietals in medial contact, in contact with posterior three supraoculars and in narrow contact with frontal ( Fig. 1E ); interparietal smaller, diamond-shaped; parietal eye spot absent; parietals in contact behind interparietal, in contact anteriorly with last supraocular, last supraciliary, and uppermost postsubocular; a transversely enlarged nuchal on each side, smaller than transversely enlarged scale separating it from upper secondary temporal.

Anterior loreal slightly smaller than posterior, higher than long; posterior loreal longer than high ( Fig. 1F ); preocular longer than tall; presuboculars three (R) and two (L); postsuboculars four, lowest interdigitated between penultimate and antepenultimate supralabials, uppermost overlapping anterior corner of parietal; lower eyelid scaly, moveable, with a clear palpebral disc smaller than size of ear opening, scales of upper palpebral series 10 (R) and 11 (L), of lower palpebral series 13; supraciliaries ten, first in contact with prefrontal, last expanded medially behind posterolateral margin of fourth supraocular, none interdigitated with supraoculars; primary temporal single, interdigitated between last two supralabials; secondary temporals two, upper larger than lower, more elongate and overlapping it; supralabials seven, fifth below eye and in contact with small scales of lower eyelid; postlabials two; ear opening moderately large, without lobules.

Mental single; postmental single, contacting first two infralabials; infralabials six; three pairs of enlarged chin shields, the first pair in medial contact, second pair narrowly separated by single medial scale, third pair separated by three medial scales; a single postgenial separating third chin shield from sixth infralabial.

Body scales smooth, in 29 longitudinal rows at midbody; paravertebral scales 60; medial precloacal scales overlap lateral precloacals.

Scales on dorsal surface of fourth toe in two paired rows proximally, single row distally beginning at last joint, four single dorsal scales; subdigital lamellae on fourth toe 20 (R) and 19 (L), smooth.

In preservative, dorsal ground color medium brown mid-dorsally, scales typically narrowly margined laterally with dark brown. Pale yellow-brown, zigzag dorsolateral stripe margined above with row of small dark-brown spots and below by row of large dark-brown spots ( Fig. 2C ), the latter giving the appearance of a dark-brown lateral field extending to ear opening and continuing more brokenly to eye ( Fig. 1F ). Sides below these large dark-brown spots pale brown, with scattered white and dark-brown flecks. Head brown, heavily marked with dark brown, both on margins and within scales; labials paler, marked with dark brown at sutures. Tail medium brown, sparsely flecked with dark brown; limbs same but with denser flecking. Ventral surfaces pearl white, with slight dusting of brown along lateral margins of chin and throat, with small dark-brown flecks on posteriormost abdomen, under hindlimbs, and under tail. Most scales on palmar and plantar surfaces brown.

Variation. Adult body size varies from 50–58 mm SVL (mean = 53.0, SD = 1.24), females appear to attain a slightly larger body size than males, and males may have slightly larger snouts than females ( Table 1). The sole juvenile has a relatively shorter trunk, longer snout, and higher posterior loreal than the adults ( Table 1). Numbers of lamellae under the fourth toe vary little, ranging from 17–21 (mean = 19.2, SD = 0.195, n = 31); numbers of single scales above the fourth toe are 4 (n = 24), 5 (n = 6), six (n = 4), or seven (n = 1); numbers of midbody scale rows vary from 26–32 (mean = 28.5, SD = 0.273); and numbers of paravertebral scales range from 50–63 (mean = 57.2, SD = 0.767) ( Table 1). There are almost always seven supralabials, with the fifth below the eye, though two specimens have eight on one side. Infralabials are usually six, but seven are found on one side in four specimens and on both sides in one specimen. Supraciliaries are usually nine, but eight are found on one side in two specimens, and ten are found on one side in four specimens and on both sides in another three. The nasal is divided by a shallow upper suture on the right side in BPBM 16775 and 16785 but is entire in all other specimens. Presuboculars two (n = 19) or three (n = 23); postsuboculars four (n = 35) or five (n = 5). The nuchal is frequently smaller than the lateral scale separating it from the upper secondary temporal—as seen in the holotype—but is usually equivalent in size to it, and larger in three specimens. All but one specimen have three pairs of enlarged chin shields, with only the first pair in medial contact; however, BPBM 16785 has four enlarged chin shields on the right side, with the first two in medial contact with the first chin shield on the left, and with the postgenial separating the fourth chin shield from the last infralabial.

Color pattern among specimens is very similar overall, but the specimens from higher elevations (2480–2880 m a.s.l.) tend to be darker dorsally and laterally ( Fig. 3B ) than those from 1200–1490 m a.s.l. ( Fig. 3C ), as is the sole juvenile. The obvious difference in lateral coloration in those two animals has lessened in preservative, with BPBM 16775 ( Fig. 3B ) having become paler laterally.

Color in Life. In life, BPBM 16765 was noted as “Dorsum brown with black edging to scales. Dorsolateral line of light spots. Sides black with many small yellow flecks more or less arrayed in horizontal rows. Venter deep lemon yellow from chin through first half of tail.” Some animals had a dark lateral field below the dorsolateral black stripe ( Fig. 3B ), but many had whitish sides below the dorsolateral stripe ( Fig. 3C ). BPBM 16761 had the chin and throat white and the remaining ventral surfaces of the body, tail, and limbs deep lemon yellow; the palmar and plantar surfaces had a lemon-yellow ground color with most scales suffused with brown ( Fig. 3D ). BPBM 16766 and most other animals had a white chin whereas the remainder of the venter was yellow. BPBM 16780 was entirely white below instead of yellow.

Etymology. The species is named in honor of Mr. Andy Sabin for his generous financial support of my work in New Guinea.

Distribution. Known from 1200–2740 m on the northern slopes of Mt. Simpson, Milne Bay Province, PNG ( Fig. 4 ). No doubt found in similar habitats in this same elevational range on the southern slopes of Mt. Simpson in Central Province, but it remains to be determined how widely ranging this species is in the southern Owen Stanley Range.

Ecological Notes. We obtained this species in native montane grassland/shrubland from 2480–2880 m a.s.l. ( Fig. 5B, C ) and in village gardens and adjacent anthropogenic grasslands from 1200–1490 m a.s.l. ( Fig. 5D ). The montane grassland/shrublands were largely formed by Deschampsia grass with Styphelia and Dodonaea shrubs interspersed along with additional plants I could not identify. So far as I can tell this species is terrestrial and heliophilic. Lizards were active when the sun was not obscured by clouds but quickly disappeared as clouds hid the sun. The rounded body of this species is consistent with its terrestrial habits. An undescribed species of Papuascincus was found in syntopy with this species.

Six females each have two developing embryos with large yolk sacs. In two of these females collected at 2480 m a.s.l. the embryos are sufficiently developed that scales are apparent on them; in another female collected at the same time and place and a second obtained at 1200 m a.s.l., the embryos are at younger stages of development, with no sign of scale development yet. Females with developing embryos range in size from 54.0–60.0 mm SVL; the sole female with a small ovum was 53.0 mm SVL; the three females with only oocytes ranged from 53.0–57.0 mm SVL. The similarity in sizes among these females suggests that all were mature; the earlier development of the embryos at lower elevation suggests that reproduction is likely aseasonal.

Figures

FIGURE 1. (A) Dorsal, and (B) lateral views of head of Lobulia elegans, holotype, BMNH 96.10.31.9, Mt. Victoria; (C) dorsal, and (D) lateral views of head of L. elegans, BPBM 18692, Fane, 1400 m a.s.l., Central Province, PNG; and (E) dorsal, and (F) lateral views of head of Lobulia sabini sp. nov., holotype, BPBM 16766, N slope Mt. Simpson, 2480 m a.s.l., Milne Bay Province, PNG. Scale bar = 5 mm.

FIGURE 2. Dorsal views of (A) Lobulia elegans, holotype, BMNH 96.10.31.9, Mt. Victoria; (B) Lobulia elegans, BPBM 18692, Fane, 1400 m a.s.l., Central Province, PNG; and (C) Lobulia sabini sp. nov., holotype, BPBM 16766, N slope Mt. Simpson, 2480 m a.s.l., Milne Bay Province, PNG. Scale bar = 10 mm.

FIGURE 3. Portraits in life of (A) Lobulia elegans, BPBM 18692, Fane, 1400 m a.s.l., Central Province, PNG; (B) Lobulia sabini sp. nov., paratype, BPBM 16775, N slope Mt. Simpson, 2480 m a.s.l., Milne Bay Province, PNG; (C) Lobulia sabini sp. nov., paratype, BPBM 16761, Bunisi Village, 1420 m a.s.l., Milne Bay Province, PNG; (D) ventral view of BPBM 16761.

FIGURE 4. Map of southeastern New Guinea, showing the type locality for Lobulia elegans (filled circle), other known localities for L. elegans (open circles), type locality for L. lobulus (square), and type locality for L. sabini sp. nov. (star).

FIGURE 5. Habitats for (A) Lobulia elegans, Hane Valley, outside Fane, 1400 m a.s.l., Central Province, PNG; (B) looking to summit of Mt. Simpson from camp at 2480 m a.s.l., showing Deschamspsia grasslands in which Lobulia sabini sp. nov. resides; (C) closer view of Deschamspsia grasslands at 2480 m a.s.l.; and (D) looking down on Bunisi Village, 1420 m a.s.l., showing the surrounding disturbed grasslands in which L. sabini sp. nov. is found.