Two new species of monitor lizards (Squamata: Varanus) endemic to the Louisiade and Tanimbar Archipelagos with a key to the subgenus Euprepiosaurus Author Weijola, Valter Author Kraus, Fred text Journal of Natural History 2023 2023-06-21 57 13 - 16 947 975 http://dx.doi.org/10.1080/00222933.2023.2218574 journal article 60679 10.1080/00222933.2023.2218574 eeb76dde-544a-4e23-8597-979f0540d5ab 1464-5262 8221626 Varanus louisiadensis sp. nov. ( Figures 3–6 ) Holotype ZMUT Sa 197 ( Figures 3 , 4 ) collected by Valter Weijola , 22 April 2013 , at Bwagaoia , Misima Island , Milne Bay Province , Papua New Guinea . Paratypes Papua New Guinea : Milne Bay Province : AMNH 76828 , ZMUT Sa196, Sa198 ( Misima Island ), ZMUT Sa199 ( Figure 5 )–200, AMNH 76755 (Rambuso, Sudest Island ), ZMUT Sa201 ( Figure 6 ), AMNH 76735–76737 (Saman [ ZMUT ], Jinian [ AMNH ], Rossell Island ) . Etymology The specific epithet refers to the Louisiade Archipelago of Milne Bay Province , Papua New Guinea , where this species is endemic. Diagnosis Varanus louisiadensis sp. nov. is a member of the subgenus Euprepiosaurus , which is defined by having the unique combination of an asymmetric sperm groove on the hemipenis and a laterally compressed tail ( Ziegler et al . 2007 ). Molecular phylogenetic analyses place it within the V. indicus species group defined by the unilateral paryphasmata ornamentation of the hemipenis and lack of blue pigmentation on the tail ( Ziegler et al . 2007 ; Weijola et al . 2019 ). It can be distinguished from all other species of Euprepiosaurus by its unique combination of: (1) dorsum black with more-or-less well-defined crossbands composed of yellow ocelli and/or dots, better defined in juveniles and subadults than adults; (2) tail black with distinct yellow bands, better defined in juveniles and subadults than adults; (3) tongue tines and a variable section of the mid-dorsal tongue surface dark grey, the remainder being pink; (4) pink-orange pigmentation usually present on cheeks and sides of neck; (5) venter pale yellow; (6) mid-body scale rows (S) 142–163; (7) mid-dorsal scale rows (XY) 139–169; (8) ventral scale rows (T) 101–113; (9) scales around neck (m) 101–118. Comparisons. Varanus louisiadensis sp. nov. can be distinguished from V. doreanus and V. jobiensis (both present in Milne Bay Province but not in the Louisiade Archipelago) by the lack of blue pigmentation on the tail (vs present in V. doreanus and V. jobiensis ); and from V. chlorostigma by the presence of yellow dorsal ocelli (vs absent in V. chlorostigma ) and the bi-coloured pink/grey tongue (vs completely grey/blue in V. chlorostigma ). Figure 3. Dorsal, ventral and head profile of the holotype (ZMUT Sa197) of Varanus louisiadensis sp. nov. Within the V. indicus group, Varanus louisiadensis sp. nov. is only likely to be confused with the remotely allopatric V. colei , V. douarrha , V. finschi , V. indicus or V. lirungensis , with which it shares a similar dorsal pattern composed of transverse bands of yellow ocelli. It is similar to V. colei in most scalational characters, but has slightly higher averages of S (153.5 vs 146) and m (109.6 vs 102.3) scale counts, and lacks the bright white gular region that characterises V. colei . It can be distinguished from V. douarrha by its uniformly yellow/ orange throat (vs marbled with dark grey in V. douarrha ) and its higher average S (153.5 vs 140.9), T (107.4 vs 96.9), XY (153.3 vs 136) and m (109.6 vs 100.7) scale counts. It can be distingushed from the more distantly related V. finschi by having a pink tongue with dark pigmentation on the distal part (vs a uniformly pink-white-yellow tongue in V. finschi ), and from V. indicus by the lack of a distinct yellow temporal band (vs present in V. indicus ). It can be distinguished from V. lirungensis by its average higher scale counts for characters Q (92.1 vs 83), S (153.5 vs 141.6), T (107.4 vs 97.5), XY (153.3 vs 139.8) and m (109.6 vs 97.8). Figure 4. The holotype (ZMUT Sa197) of Varanus louisiadensis sp. nov. on Misima Island (photo VW). Description of the holotype . Well-preserved juvenile with a small incision on left thigh from where tissue was removed. Dorsal ground colour of body, tail, head and limbs black, covered by distinct crossbands of yellow rosettes and dots. Habitus slender; total length 585 mm (SVL = 240 mm , F = 345 mm ); tail 1.44 times as long as body, 36.3 times as long as high ( 9.5 mm ) at midlength, round at base, becoming laterally compressed distally, and with mid-dorsal ridge two scales wide starting at about 30 mm from base. Thirteen discernible cream-coloured crossbands on distal ¾ of the tail. Venter cream yellow, marmorated with brown, with incomplete crossbands between hind legs and gular fold that are one scale row wide. Throat cream with scattered brown scales laterally. Ventral surfaces of limbs cream with narrow, pale-brown bands and dots. Under tail cream with interspersed brown scales at base of tail. Dorsal surfaces of limbs black with yellow dots, stripes, and ocelli composed of about 1–8 scales. Figure 5. Paratype (ZMUT Sa199) of Varanus louisiadensis sp. nov. on Sudest Island (photo VW). Head 1.82 times as long as wide, black with yellow dots and short stripes and with bright-yellow parietal scale. Well-defined temporal bands or postocular stripes lacking on both sides of head. Labial scales white at snout but each from below nostril to labial commissure with a brown dot. Nostrils oval, situated slightly nearer to snout than eye. Nasal capsules expanded, with shallow sagittal groove on rostrum. Nuchal scales irregular in shape on anterior part of the neck, round on mid-neck, smaller and elongate on lower neck, all surrounded by granules. Dorsal scales somewhat irregular in size, elongate, keeled, each surrounded by few granules, most with single pit. Lateral caudal scales regular in size and shape, rectangular, flattened, usually with single posterior pit. Mid-ventral caudal scales twice as wide as mid-dorsal caudal scales, elongate, with sharp keel. Mid-ventral scales rectangular, flat, posterior margin rounded and bordered by row of granules. Scales on chest irregular in size, round to polygonal, each surrounded by few granules. Gular scales roundish to polygonal, each surrounded by granules. Mental scales elongate, rectangular to polygonal. Infrafemorals and infratibials round, each surrounded by row of granules along lateral and posterior margins. Infracarpals and infratarsals round and highly domed, with brown traction pads on most scales. Subdigital scales domed, of irregular size and shape. Fourth toe with row of 11 (R) and 12 (L) enlarged scales along outer margin; third toe with four slightly enlarged scales along outer margin. Claws dark brown, sharp, and recurved. Figure 6. Paratype (ZMUT Sa201) of Varanus louisiadensis sp. nov. on Rossell Island (photo VW). Occipital scales flattened, relatively small, irregularly polygonal. Supraocular scales 8 (R) and 7 (L), enlarged, irregular in shape and size, each densely covered with pits. Scales of forehead and rostrum polygonal, flattened, larger than occipital scales. Supralabials pentagonal or rectangular, covered with pits. Infralabials of irregular size, pentagonal or polygonal. Tines of tongue blue, its trunk pink, except for thin, blue median line on both dorsal and ventral sides. Scale counts. S: 157, XY: 155, DOR: 164, T: 103, VEN: 123, X: 43, m: 105, P: 42, Q: 93. Measurements. SVL: 240 mm , F: 345 mm , TL: 585 mm , E: 135 mm , D: 84 mm , A: 40 mm , B: 22 mm , C: 15.5 mm , G: 10.5 mm , H: 8.5 mm , I: 21.5 mm . Scale counts, measurements and proportion indices of the type series. See Table 3 . Variation and colouration in life. Variation is mostly seen in the dorsal crossbands which can be composed of either spots and ocelli or spots only ( Figures 4–6 ). Judging from the material at hand these also tend to become less distinct as the animals age. The extent of grey pigmentation on the tongue varies considerably between individuals, varying from colouring only the tines to encompassing the whole dorso-distal half of the trunk. Table 3. Scale counts, measurements (in mm), and mensural ratios for the type series of V. louisiadensis sp. nov. and V. tanimbar sp. nov.

P	Q	R	S	T	VEN	N	X	XY	DOR	C	M	SVL	F	TL	A	B	C	G	H	1	10	11
Varanus louisiadensis sp. nov.
AMNH 76736	Rossell	41	91	61	157	112	132	94	42	148	163	28	114	125	165	290	24.5	13	9	6	6	1.32	1.88	2.72
AMNH 76737	Rossell	47	88	58	142	108	125	91	40	139	152	28	112	115	155	270	24	12	9	5.5	5.5	1.35	2.0	2.67
AMNH 76755	Sudest	47	100	66	163	107	128	101	43	158	170	25	110	145	205	350	29.5	16	11	7.5	6.5	1.41	1.84	2.68
AMNH 76828	Misima	47	86	53	152	103	119	93	45	148	160	25	118	205	300	505	36	19.5	14	11	8	1.46	1.85	2.57
AMNH 76735	Rossell	42	91	55	151	106	126	88	45	155	170	26	101	270	400	670	49	27	18	11	10.5	1.48	1.81	2.72
ZMUT Sa196	Misima	41	90	59	154	101	119	89	41	146	158	26	109	320	480	800	52	26	18	14	13	1.50	2.0	2.89
ZMUT Sa197	Misima	42	93	60	157	103	123	87	43	155	164	25	105	240	360	600	40	22	15	11.5	9	1.50	1.82	2.67
ZMUT Sa198	Misima	44	90	60	147	110	129	95	41	149	160	26	103	305	470	775	51	27	17	15	12	1.54	1.89	3.0
ZMUT Sa199	Sudest	43	100	62	161	106	123	90	47	169	184	26	107	460	630	1090	68	35	23	21	16	1.94	2.96
ZMUT Sa200	Sudest	44	97	66	161	112	134	94	42	168	180	25	118	460	710	1170	70	37	25	22	17	1.54	1.89	2.80
ZMUT Sa201	Rossell	40	87	60	144	113	132	91	42	151	163	25	109	400	540	940	62	33	23	18	16	1.88	2.70
V. tanimbar sp. nov.
WAM112255	Yamdena	43	91	58	158	107	128	91	44	159	170	24	109	187	295	482	36.3	19.5	14.5	11.3	8.4	1.59	1.86	2.50
WAM109940	Yamdena	48	93	65	161	109	128	93	44	170	182	21	113	170	255	425	34.7	18	12.9	10.6	7.5	1.50	1.93	2.69
WAM112323	Selaru	46	95	60	145	107	125	92	48	162	173	21	119	305	61.7	34	24	20.5	14	1.81	2.57
WAM109896	Yamdena	42	89	63	152	107	126	90	45	164	175	22	109	390	680	1070	72	37	25.7	21.8	14.7	1.74	1.95	2.80

Range. Varanus louisiadensis sp. nov. has been recorded from coastal and lowland areas on all three major islands of the Louisiade Archipelago: Misima, Sudest, and Rossel ( Figure 7 ). Considering the good dispersal abilities of monitors in the V. indicus group it can also be expected to occur on nearby smaller islands with suitable habitat, such as Paneati and Panatinane islands, but its presence on satellite islands of the Louisiade Archipelago has yet to be confirmed. Natural history. Varanus louisiadensis sp. nov. does not appear to be particularly abundant on any of the larger islands in the Louisiades, and active searches on Misima, Sudest and Rossell by VW in 2013 resulted in a total of 16 sightings and five collected specimens over the course of three weeks. All of these observations were made around the coast in stands of mangrove or other coastal woodlands, often intermixed with coconut plantations. Figure 7. Map of the Papuan region (A) with the Tanimbar Islands (B) and Louisiade Archipelago (C) enlarged. The type locality of Varanus louisiadensis sp. nov. on Misima island is indicated with a filled circle, and additional collection localities for the paratypes on Sudest and Rossell are indicated by open circles. The type locality of V. tanimbar sp. nov. , Latdalam, is indicated by a filled star, and the collection locality of one of the paratypes at Adaut, Selary Island, with an open star. Remarks The molecular phylogeny of Euprepiosaurus published by Weijola et al . (2019) retrieved monophyly of the samples of V. louisiadensis sp. nov. from Misima, Sudest, and Rossel with high support. The samples from Misima and Sudest were genetically most similar and formed a sister group to those from Rossel. Varanus louisiadensis sp. nov. formed a sister lineage to V. chlorostigma ; that relationship was not well supported, but it is sensible on geographic grounds alone. The shortest ND4 (NADH dehydrogenase subunit 4) pairwise distances of V. louisiadensis sp. nov. are to V. chlorostigma (3.3%) and Varanus sp . from the Admiralty Islands (3.4%).