Toxicocalamus longhagen, Roberts & Iova & Austin, 2022

Roberts, Jackson R., Iova, Bulisa & Austin, Christopher C., 2022, A new species of New Guinea Worm-Eating Snake (Serpentes, Elapidae, Toxicocalamus Boulenger, 1896) from Western Highlands Province, Papua New Guinea, Zoosystematics and Evolution 98 (2), pp. 399-409 : 399

Toxicocalamus longhagen sp. nov.

Figs 2 , 3 , 4 , 5

Holotype.

PNGM 22160, Dobel, Mt. Hagen Town, -5.837603, 144.278022, 1,650 meters a.s.l., 25 February 1967, collector unknown.

Etymology.

The specific epithet, longhagen, is a combination of “long” - a Tok Pisin word meaning ‘from’ and “hagen” that refers to the type locality of Mt. Hagen Town (Fig. 1 ). Tok Pisin is a uniting and official language of Papua New Guinea, the most linguistically complex region on the planet with more than 800 unique languages ( Foley 2010).

Diagnosis.

A medium-sized species with moderate habitus (566.0 total length, 12.8 maximum lateral width) with 15-15-15 dorsal scale rows, 200 ventral scales, 43 paired subcaudals, preocular present and not fused to prefrontal, preocular not in contact with internasal or nasal; prefrontal separating preocular from internasal and nasal by contacting second supralabial; frontal not fused with supraoculars; internasals not fused; four circumoculars - one supraocular, one preocular, two postoculars; nasals divided; one anterior temporal not fused with supralabials, one posterior temporal; six supralabials, the second in contact with prefrontal, preventing contact between nasal and preocular; cloacal plate divided; ventrals yellowish with light to dark brown.

Toxicocalamus longhagen can be distinguished from T. holopelturus McDowell, 1969 by having paired subcaudals (vs. single); from T. mintoni Kraus, 2009, T. cratermontanus Kraus, 2017, T. stanleyanus Boulenger, 1903, T. misimae McDowell, 1969, T. longissimus Boulenger, 1896, T. buergersi (Sternfeld, 1913), and T. preussi (Sternfeld, 1913) by having preocular not fused to prefrontal (vs. fused); from T. pumehanae O’Shea, Allison & Kaiser, 2018 by having prefrontal distinct from internasal (vs. fused); from T. goodenoughensis Roberts & Austin, 2020, and T. pachysomus Kraus, 2009, by lacking contact between internasal and preocular (vs. internasal and preocular in contact); from T. nigrescens Kraus, 2017, T. loriae (Boulenger, 1898), T. spilolepidotus McDowell, 1969, T. grandis (Boulenger, 1914), and T. ernstmayri by having preocular lacking contact with nasal (vs. preocular contacting prefrontal and nasal).

In having prefrontal in contact with second supralabial, preventing contact between preocular and either internasal or nasal, T. longhagen is most similar in head scalation to T. mattisoni Kraus, 2020. It can be further distinguished from T. mattisoni by presence of two postoculars (vs. one), by having one large posterior temporal (vs. two posterior temporals), and presence of more ventrals (200 vs.170-181).

Toxicocalamus longhagen has scalation similar to some specimens of Apistocalamus loennbergii Boulenger, 1908, a taxon currently in synonymy with T. loriae ( Kraus 2017; Kraus 2020); specifically, in both the new species and some A. loennbergii specimens, the prefrontal scale contacts the second supralabial, preventing preocular and nasal scale contact. Kraus (2020) described A. loennbergii as having "preocular and nasal scales [that] may or may not be in contact" because they are barely separated on just the right side in the lectotype (BMNH 1946.1.18.24) but bilaterally in contact in the two paralectotypes (BMNH 1946.1.18.25-26). Disregarding this character, T. longhagen can still be distinguished from A. loennbergii by having two postoculars (vs. 1, "exceptionally two" sensu Boulenger 1908), fewer ventrals (200 vs. 213-218), and more subcaudals (43 vs. 22-32).

Description of the holotype.

Adult male confirmed by µCT scans showing the presence of well-developed hemipenes, length 19.0, width 3.2 (1.6 each) (Fig. 3 ). Total length 566.0, snout-vent length 476.0, tail length 90.0, eye-naris distance 2.8, internarial distance 2.8, head length 12.7, head width 8.6.

Rostral broader (3.2) than tall (2.4); internasals near triangular, wider (2.2) than long (1.3); prefrontals pentagonal, unfused to preoculars (Fig. 4D, E ), as long (2.8) as they are wide (2.8); preocular fan-shaped, not fused with supraocular and not in contact with internasal or nasal (Fig. 4A, B ); parietal scales longer (5.7) than wide (each 3.5), parietal suture 4.0. Nasals divided, separated by large nares; postoculars two, top postocular 3 × larger than bottom postocular; anterior temporal single, rectangular, positioned above and in contact with fifth and sixth supralabials; posterior temporal single, positioned between sixth supralabial and parietals. Supralabials six, third and fourth in contact with eye; infralabials six, first four in contact with genials (first three with anterior genials, fourth with posterior genials). Mental triangular, wider (2.0) than tall (1.3); anterior genials in contact, anterior margin bordering first infralabials; posterior genials separated from each other along entire interior margin by intergenial gular (2.7 long by 1.7 wide) and separated entirely from fifth infralabial by two lateral gulars. Eye small (diameter 1.6); pupil round.

Dorsal scale rows 15-15-15, smooth without apical pits. Ventrals 200, 5 × wider than long; paired subcaudals 43. Cloacal plate divided, wider (6.3) than long (2.5). Tail with conical spine (length 3.3).

Maxilla with six (right) and five (left) teeth, both sides with maxillary positions for two grooved envenoming front fangs (II,4 / II,3; but each side appears to be missing one of the front envenomating fangs); dentary with 11 (right) and 12 (left) teeth, front three (four on right) separated from remaining posterior dentary teeth by 0.5 mm; palatine with six (right) and seven (left) teeth; pterygoid with 15 and 16 (left) teeth that extend posteriorly past basisphenoid and basioccipital suture. Postfrontal bones present, triangular or teardrop in shape, curved and extending ventrally at roughly 45-degree angle from skull ( Roberts and Austin 2020).

Color in preservative.

Color in life is unknown but color in preservative is atypical for the genus. This may reflect the specimen’s preservation position; rather than a coil, the specimen’s resting position is that of a crumpled-up ball. This fixation position appears to have affected the coloration; at the sharpest turns in the body, the scales facing the outside of the balled-up snake are almost all uniformly pale yellow while those on the inner surfaces (presumably protected more from light damage) are variable shades of dark mousy brown depending on the position along the body (closer to the tail = darker brown). Based on these observations, we suggest that this irregular color pattern has been the product of light exposure, and the intense crumpling of the specimen has facilitated color loss differentially across the body in the specimen. Nonetheless, we describe the current color pattern of the specimen below.

Dorsal head scales almost entirely mousy brown, becoming light yellow laterally on sides of the face once reaching the middle of the supralabials. Dorsum becomes lighter beyond second dorsal scale row behind parietals. Along spine, dorsal scale rows retain small amount of brown, but brownish yellow dominates; a dark vertebral patch of brown, roughly 3 dorsal scale rows in width, present at level of 66th ventral scale. A second dark vertebral patch posterior to first patch at 76th ventral, is roughly 7 scale rows in width; these dark brown patches connect on the right side of body by light brown dorsal scales. Dorsal scales posterior to second brown patch (excluding first row), with pale-yellow background overlain by mousy brown that darkens towards tail; tail darker brown than all other dorsal surfaces.

The lightest ventral scales are on the anterior and posterior thirds of the body, with the scales near mid-body being darker brown than all other ventrals. Each ventral scale darkens anteriorly, with the posterior of each scale light yellow. The ventrals of the first and last third of the body are more contrasting, with the anterior margin of these scales obviously darker brown than the brownish yellow color of the posterior margin. In the mid-body, the darkest ventral scales are almost uniformly dark brown with no yellow posterior margin.

The subcaudals are nearly uniform in color and pattern, with the anterior margin dark brown with a yellow posterior margin. As the subcaudals approach the tail tip, the proportion of dark brown to yellow increases, with the last eight paired subcaudals almost entirely dark brown. The base of the conical tail tip is dark brown, with the rest of the tip the same yellow as that of the subcaudals.

Two red embossed dymo tags (numbers 10198 and 1580) are tied along the neck. The anteriormost tag (10198) has been tied so tightly that the dorsal and ventral scales are damaged and partially torn. The official PNGM catalog tag has its own string but is tied to this anterior 10198 tag as well. Other damages to the specimen include three lacerations to the dorsum that probably occurred during field collection.

Distribution.

Currently, T. longhagen is only known from the holotype, collected in Dobel Village (1,650 m a.s.l., -5.837603, 144.278022), Mt. Hagen Town, Western Highlands Province, Papua New Guinea. This area now, according to satellite imagery, is within a developing portion of Mt. Hagen Town comprising small structures and small-scale tilled plots of land and gardens. We also examined vouchers of T. loriae from three localities from Chimbu Province in the Waghi Valley east of the T. longhagen type locality (Dobel Village): Kup near Mt. Kubor (58 km straight-line distance from Dobel Village), Kondiu (66 km), and Kundiawa (79 km). Based on the straight-line distance from type locality and some morphological similarities, these specimens may be conspecific but we are not confident of this and do not include them as conspecific at this time.

Deposited material.

µCT scans of holotype comprise scans of the body and CLAHE corrected scans of the head deposited on Morphosource (Identifier - PNGM 22160).

Figures

Figure 1. Map of New Guinea and its adjacent islands. Markers indicate type localities of all accepted species of Toxicocalamus Boulenger, 1896. The new species, Toxicocalamus longhagen, is marked by a diamond with inset asterisk. The type species of the genus, T. longissimus Boulenger, 1896, is marked by a star on Woodlark Island. Black circles with numbers represent the type localities for the remaining congenerics (numbered longitudinally west-to-east): 1) T. grandis (Boulenger, 1914), 2) T. ernstmayri O'Shea, Parker, and Kaiser 2015, 3) T. preussi anguisinctus Bogert & Matalas, 1945, 4) T. buergersi (Sternfeld, 1913) (precise locality unknown, placement based on O'Shea et al. 2018), 5) T. preussi preussi (Sternfeld, 1913), 6) T. cratermontanus Kraus 2017, 7) T. spilolepidotus McDowell, 1969, 8) T. stanleyanus Boulenger, 1903, 9) T. loriae (Boulenger, 1898), 10) T. pumehanae O'Shea, Allison & Kaiser, 2018, 11) T. mattisoni Kraus, 2020, 12) T. pachysomus Kraus, 2009, 13) T. goodenoughensis Roberts & Austin, 2020, 14) T. nigrescens Kraus, 2017, 15) T. misimae McDowell, 1969, 16) T. mintoni Kraus, 2009, and 17) T. holopelturus McDowell, 1969. Localities have not been indicated for current subjective synonyms of T. loriae. For thorough taxonomic history and localities of these taxa, please see Kraus (2017), O'Shea et al. (2018), O'Shea et al. (2021).

Figure 2. Photographs of A. Dorsal B. Ventral views of the holotype of Toxicocalamus longhagen (PNGM 22160). Metallic rectangles in image B are specimen probes used to pin specimen down for ventral scale visualization. Scale bar indicates 5 cm.

Figure 3. A µCT scan of the holotype of T. longhagen (PNGM 22160) showing the A. Whole body (scale bar 20 mm) and the B. Hemipenes (scale bar 5 mm) highlighted in purple.

Figure 4. Photograph, line illustrations, and 3 D µCT renderings of the right (A-C) and dorsal (E-F) views of the holotype of T. longhagen (PNGM 22160). Scale bars: 5 mm.

Figure 5. µCT scans of the A) holotype of T. longhagen (PNGM 22160) with the prefrontal bones highlighted in purple with closer dorsal and anterior views and a B) voucher from the type locality of T. loriae (LSUMZ 129270) with the prefrontals highlighted in yellow. Skull scale bars are 5 mm and postfrontal scale bars are 0.5 mm.