Stegonotus ayamaru KAISER, O’SHEA & KAISER, 2019
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Stegonotus ayamaru
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| Higher Taxa | Colubridae, Colubrinae, Colubroidea, Caenophidia, Alethinophidia, Serpentes, Squamata (snakes) |
| Subspecies | |
| Common Names | E: Ayamaru Groundsnake |
| Synonym | Stegonotus ayamaru KAISER, O’SHEA & KAISER 2019 |
| Distribution | Indonesia (West Papua) Type locality: “Komara” [Kamro], Aitinyo District, Maybrat Regency, West Papua Province, Indonesia (1.5103°S, 132.3763°E; elevation ca. 140 m; Fig. 1). The type locality is a village of the Ayamaru people inhabiting the central Bird’s Head Peninsula. |
| Reproduction | |
| Types | Holotype: RMNH RENA 31199, an adult male. The specimen was collected in February 1953 by the Reverend Herbert Marcus (1883–1961) and his wife Mieneke Marcus-van den Nieuwenhuizen (1911–2009). In addition to the village name, the original specimen label also gives the local name for the specific collection site as “apan bebach,” but this appears to be a local designation and we were unable to determine its precise locality. In order to determine the detailed locality of the village listed as “Komara,” we located the name on Map SA 53-1 (Army Map Service 1942), the most likely map of the area available to missionaries in the 1950s. On this map, there is a village listed under the name Komara, which we confirmed as the correct locality based on the accounts of the missionaries (Marcus-van den Nieuwenhuizen 2009). The map in Elmberg (1968: Fig. 2) reflects this arrangement and indicates that Komara was a village with school activity, making it a very likely residence for missionaries. This location is now known as Kamro. The initial identification of the specimen as S. batjanensis was done by Dr. Maria S. (“Riet”) Knaap-van Meeuwen (born 1936) in March 1962. |
| Diagnosis | Diagnosis. Stegonotus ayamaru appears to be a relatively small-sized (SVL of only known specimen = 493 mm) member of the genus with a relatively long tail (SCR♂ = 0.37). It can be distinguished from all other known Stegonotus by the following combination of characters: (1) rostral extending onto the dorsal part of the head and not intruding into the internasal area, resulting in a relatively long internasal suture (character state: gull wing +; Fig. 3C in Kaiser et al. 2019); (2) area of prefrontals 1.5 times that of the internasals, internasal suture two-thirds the length of the prefrontal suture (Fig. 7A); (3) frontal clearly pentagonal with well-formed corners and a slightly convex anterior suture; (4) AE lies behind the anterior end of frontal (Fig. 7A’); (5) length of frontal equal to that of the parietal suture; (6) PF ( ≥ 90° (Fig. 7A’); (7) AP ( = 135° with lateral ray directed laterally (Fig. 7A’); (8) three temporal scales touching the parietals, the lengths of the two anterior temporals combined equaling the length of the posterior temporal, temporal formula 2+2+3; (9) three neck scales contacting parietals (10) loreal two-thirds as long as wide; (11) a single preocular with dimensions similar to those of the loreal, curving around the anterior border of the eye (Fig. 5B’); (12) seven supralabials, three (SL3–5) touching the eye; SL5 projecting forward from behind the eye to form a narrow contact zone with the eye (Figs. 5B, B’, 6A’); (13) eight infralabials, four (IL1–4) touching the anterior genial, two-thirds of IL4 in contact with the anterior genial (Fig. 5D’); (14) four chin scales separating the posterior genial and the anteriormost gastrostege; (15) 17-17-15 dorsals; 181 ventrals, 105 paired subcaudals; (16) cloacal plate entire; (17) color in preservative (65 years post-collection): dorsum Maroon (29) fading laterally to Hazel (26), head Maroon with areas on the frontal and parietals that are a lighter color (Hazel); nasals Light Buff (2) with some darker areas (Hazel); venter Light Buff (Figs. 4, 5). On the ventral surface, the anterior to medial portions of the subcaudals are Hazel, creating a dark tail (Fig. 4C in Kaiser et al. 2019, as all figure references in this section). Comparisons. In the comparisons that follow, characteristics of S. ayamaru are listed in parentheses. Species names are followed by the number of specimens used to determine ranges of continuous characters. Since the only known specimen of S. ayamaru is a male, we limit our comparisons of characteristics with potential sexual dimorphism (see Kaiser et al. 2018) to male specimens; gender is indicated throughout by subscripted male (♂) and female (♀) symbols for ease of reference. A listing of those characters most relevant for interspecies comparisons is provided in Table 2 in Kaiser et al. 2019. Stegonotus admiraltiensis (n = 1) differs from S. ayamaru by scale counts of V♂ = 208 (181), SC♂ = 98 (105), SCR♂ = 0.32 (0.37), D = 17-19-15 (17-17-15), SL = 8 (7), SLE = 4+5 (3+4+5), IL = 9 or 10 (8), and ILG = 6 (4). Additional differences include: (1) the rostral of S. admiraltiensis is clearly visible on the dorsal surface of the head, where it forms a shallow V (Fig. 3D) when viewed from above (gull wing +); (2) the rostral intrudes upon the internasal space, shortening the internasal suture (does not extend into internasal space, internasal suture not impacted); (3) InS = PfS (InS = 2⁄3 PfS); (4) the lateral ray of AP ( is directed posterolaterally (laterally); (5) FL is slightly shorter than ParS (FL = ParS); (6) two temporals contact the parietals (3); and (7) two neck scales contact the parietals (3). The closest known locality for S. admiraltiensis is on Manus Island, Papua New Guinea (PNG), ca. 1600 km by air from the type locality of S. ayamaru. Stegonotus aruensis (n = 1) differs by scale counts of V♂ = 190 (181) and SLE = 3+4 (3+4+5). Additional differences include (1) the rostral of S. aruensis is not visible on the dorsal surface of the head (Fig. 3A) (gull wing +); (2) InS = 3⁄4 PfS (InS = 2⁄3 PfS); (3) the lateral ray of AP ( is directed posterolaterally (laterally); and (4) FL = ParS (FL = ParS). The closest known locality for S. aruensis is in the Aru Islands, Maluku Province, Indonesia, ca. 500 km by air from the type locality of S. ayamaru. Stegonotus australis (n = 21) differs by scale counts of V♂ = 191–220 (181), SC♂ = 74–88 (105), SCR♂ = 0.25–0.29 (0.37), SLE = 4+5 (3+4+5); SL = 8 or 9 (7); IL = 9 or 10 (8), and ILG = 5 (4). Additional differences include (1) the rostral of S. australis is clearly visible on the dorsal surface of the head, where it forms a shallow V when viewed from above (gull wing +); (2) the rostral intrudes upon the internasal space, shortening the internasal suture (does not extend into the internasal space, internasal suture not impacted); (3) InS = 1⁄3 PfS (InS = 2⁄3 PfS); (4) the lateral ray of AP ( is directed posterolaterally (laterally); (5) FL is slightly shorter than ParS (FL = ParS); and (6) two temporals contact the parietals (3). The closest known locality for S. australis is in northern Queensland, Australia, ca. 1500 km by air from the type locality of S. ayamaru. Stegonotus batjanensis (n = 15) differs by scale counts of V♂ = 221–236 (181), SC♂ = 78–89 (105), SCR♂ = 0.25–0.29 (0.37), SL = 8, or rarely 7 (7), IL = 9, rarely 8 or 10 (8), and ILG = 5 (4). In addition, (1) in S. batjanensis SL3 projects posteriorly towards the eye to form a narrow contact zone (Fig. 6B, B’) (SL5 projects anteriorly towards the eye; Fig. 6A, A’); (2) the rostral of S. batjanensis is clearly visible on the dorsal surface of the head, where it forms a shallow V when viewed from above (gull wing +); (3) the rostral intrudes upon the internasal space, shortening the internasal suture (does not extend into internasal space, internasal suture not impacted); (4) InS = 1⁄4 PfS (InS = 2⁄3 PfS); (5) AE lies in front of the anterior edge of the frontal (AE lies behind anterior edge of the frontal); (6) FL is slightly shorter than ParS (FL = ParS); (7) one, rarely two, neck scales contact the parietals (3); and (8) a distinctive color pattern is present (no distinctive color pattern). The closest known locality for S. batjanensis is on Halmahera Island, North Maluku Province, Indonesia, ca. 500 km by air from the type locality of S. ayamaru. Stegonotus borneensis (n = 1) is a geographically distant species from Borneo, an island to the west of Wallace’s Line, with scale counts differing in V♂ = 196 (181), SC♂ = 78 (105), SCR♂ = 0.28 (0.37), SLE = 4+5 (3+4+5), SL = 9 (7), IL = 10 (8), and ILG = 5 (4). Additional differences include (1) InS = PfS (InS = 2⁄3 PfS); (2) the lateral ray of AP ( is directed posterolaterally (laterally); (3) FL = ParS (FL = ParS); and (4) two temporals contact the parietals (3). The closest known locality for S. borneensis is in northern Borneo, Sabah State, Malaysia, ca. 1900 km by air from the type locality of S. ayamaru. Stegonotus cucullatus (n = 3) differs by scale counts of V♂ = 205–216 (181), SC♂ = 84–95 (105), SCR♂ = 0.29–0.31 (0.37), SLE = 4+5 (3+4+5), SL = 8 (7), IL = 9 or 10 (8), and ILG = 5 (4). Additional differences include (1) the rostral of S. cucullatus is clearly visible on the dorsal surface of the head, where it forms a deep V (Fig. 3E) when viewed from above (gull wing +); (2) the rostral intrudes upon the internasal space, shortening the internasal suture (does not extend into internasal space, internasal suture not impacted); (3) InS = 1⁄4 PfS (InS = 2⁄3 PfS); (4) AE lies at the same level as the anterior end of the frontal (AE lies behind the anterior edge of the frontal); (5) FL = 2⁄3 ParS (FL = ParS); and (6) two temporals are in contact with the parietals (3). The closest known locality for S. cucullatus is in Manokwari, West Papua, Indonesia, ca. 200 km by air from the type locality of S. ayamaru. Stegonotus derooijae (n = 1) differs by scale counts of SC♂ = 94 (105), SLE = 3+4 (3+4+5), and ILG = 5 (4). Additional differences include (1) AE lies at the same level as the anterior end of the frontal (AE lies behind the anterior edge of the frontal); (2) PF ( is < 90° (≥ 90); and (3) three to five neck scales contact the parietals (3). The closest known locality for S. derooijae is on Salawati Island, Raja Ampat Archipelago, West Papua Province, Indonesia, ca. 200 km by air from the type locality of S. ayamaru. Stegonotus diehli (n = 1; juvenile, sex unknown) differs by scale counts of SC? = 82 (SC♂ = 105), SCR? = 0.31 (SC♂ = 0.37), D = 15-15-15 (17-17-15), and SLE 3+4 (3+4+5). Additional differences include (1) the rostral of S. diehli is barely visible on the dorsal surface of the head, where it forms a gull wing (Fig. 3B) when viewed from above (gull wing +); (2) InS = 1⁄2 PfS (InS = 2⁄3 PfS); (3) PF ( < 90° (≥ 90°); and (4) four neck scales contact the parietals (3). The closest known locality for S. diehli is Bogadjim, Madang Province, PNG, ca. 1500 km by air from the type locality of S. ayamaru. Stegonotus dorsalis (n = 1) differs by scale counts of V♂ = 208 (181), SC♂ = 88 (105), SCR♂ = 0.30 (0.37), D = 15-15-15 (17-17-15), SLE 4+5 (3+4+5), SL = 8 (7), IL = 10 (8); and ILG = 5 (4). Additional differences include (1) the rostral of S. dorsalis is clearly visible on the dorsal surface of the head, where it forms a deep V when viewed from above (gull wing +); (2) the rostral intrudes upon the internasal space, shortening the internasal suture (does not extend into internasal space, internasal suture not impacted); (3) InS = 1⁄4 PfS (InS = 2⁄3 PfS); (4) AE lies at the same level as the anterior end of the frontal (AE lies behind the anterior edge of the frontal); (5) FL = ParS (FL = ParS); and (6) three neck scales contact the parietals, two of them enlarged (3, equally sized). The closest known locality for S. dorsalis is in Madang Province, PNG, ca. 4.2280°S, 144.9333°E (see Kaiser et al. 2018a), ca. 1400 km by air from the type locality of S. ayamaru. Stegonotus florensis (n = 1) differs by scale counts of V♂ = 230 (181), SC♂ = 82 unpaired (105, paired), SCR♂ = 0.26 (0.37), D = 21-21-19 (17-17-15), SL = 8 or 9 (7), IL = 10 (8), and ILG = 5 (4). Additional differences include (1) the rostral of S. florensis is clearly visible on the dorsal surface of the head, where it forms a shallow V when viewed from above (gull wing +); (2) the rostral intrudes upon the internasal space, shortening the internasal suture (does not extend into internasal space, internasal suture not impacted); (3) InS = PfS (InS = 2⁄3 PfS); (4) AE lies at the same level as the anterior end of the frontal (AE lies behind anterior edge of the frontal); (5) the lateral ray of AP ( is directed posterolaterally (laterally); (6) FL is slightly shorter than ParS (FL = ParS); (7) PF ( < 90° (≥ 90°); and (8) a distinctive color pattern is present (no distinctive color pattern). The closest known locality for S. florensis is on Flores Island, East Nusa Tenggara Province, Indonesia, ca. 1400 km by air from the type locality of S. ayamaru. Stegonotus guentheri (n = 29) differs by scale counts of V♂ = 185–198 (181), SC♂ = 64–80 (105), SCR♂ = 0.25–0.29 (0.37), D = 15-15-13 (17-17-15), SLE 4+5, or rarely 3+4 (3+4+5), SL = 8, or rarely 7 (7), IL = 9, or rarely 8 or 10 (8), and ILG = 5 (4). Additional differences include (1) InS = PfS (InS = 2⁄3 PfS); and (2) FL is slightly shorter than ParS (FL = ParS). The closest known locality for S. guentheri is on Fergusson Island, Milne Bay Province, PNG, ca. 2100 km by air from the type locality of S. ayamaru. Stegonotus heterurus (n = 13) differs by scale counts of V♂ = 179–198 (181), SC♂ = 76–88 unpaired (105 paired), SCR♂ = 0.29–0.32 (0.37), and SLE = 3+4 (3+4+5). Additional differences include (1) the rostral of S. heterurus is generally clearly visible on the dorsal surface of the head, where it forms a shallow V when viewed from above (gull wing +); (2) the rostral intrudes upon the internasal space, shortening the internasal suture (does not extend into internasal space, internasal suture not impacted); (3) InS = –1⁄2 PfS (InS = 2⁄3 PfS); (4) AE lies at the same level as the anterior end of the frontal (AE lies behind anterior edge of the frontal); (5) the lateral ray of AP ( is directed posterolaterally (laterally); (6) FL = ParS (FL = ParS); and (7) PF ( < 90° (≥ 90°). The closest known locality for S. heterurus is Duke of York Island, East New Britain Province, PNG, ca. 2200 km by air from the type locality of S. ayamaru. Stegonotus iridis (n = 6) differs by scale counts of V♂ = 198–211 (181), SC♂ = 78–88 (105), SCR♂ = 0.28–0.30 (0.37), SLE 4+5 (3+4+5), SL = 8 (7), IL = 9 or 10 (8), and ILG = 5 (4). Additional differences include (1) the rostral of S. iridis is clearly visible on the dorsal surface of the head, where it forms a deep V when viewed from above (gull wing +); (2) the rostral intrudes upon the internasal space, shortening the internasal suture (does not extend into internasal space, internasal suture not impacted); (3) InS = PfS (InS = 2⁄3 PfS); (4) AE lies at the same level as the anterior end of the frontal (AE lies behind anterior edge of the frontal); (5) FL = ParS (FL = ParS); and (6) a distinctive color pattern is present (no distinctive color pattern). The closest known locality for S. iridis is on Salawati Island, Raja Ampat Archipelago, West Papua Province, Indonesia, ca. 200 km by air from the type locality of S. ayamaru. Stegonotus keyensis (n = 4) differs by scale counts of V♂ = 200–207 (181), SC♂ = 70–80 (105), SCR♂ = 0.26–0.28 (0.37), SLE = 4+5 (3+4+5), SL = 8, or rarely 9 (7), IL = 8, 9, or rarely 10 (8), and ILG = 5 (4). Additional differences include (1) the rostral of S. keyensis is barely visible on the dorsal surface of the head, where it forms a gull wing when viewed from above (gull wing +); (2) InS = PfS (InS = 2⁄3 PfS); (3) AE lies at the same level as the anterior end of the frontal (AE lies behind anterior edge of the frontal); (4) FL = 3⁄4 ParS (FL = ParS); (5) two temporals contact the parietals (3); and (6) five (rarely 3) neck scales contact the parietals (3). The closest known locality for S. keyensis is in the Kei Islands, Maluku Province, Indonesia, ca. 400 km by air from the type locality of S. ayamaru. Stegonotus lividus (n = 2, female specimens) differs by scale counts of V♀ = 197–199 (V♂ = 181), SC♀ = 67–68 (SC♂ = 105), SCR♀ = 0.25 (SCR♂ = 0.37), and SLE = 3+4 (3+4+5). Additional differences include (1) InS = PfS (InS = 2⁄3 PfS); (2) AE lies at the same level as the anterior end of the frontal (AE lies behind anterior edge of the frontal); (3) PF ( < 90° (≥ 90°); and (4) two or four neck scales contact the parietals (3). The closest known locality for S. lividus is on Semau Island, East Nusa Tenggara Province, Indonesia, ca. 1350 km by air from the type locality of S. ayamaru. Stegonotus melanolabiatus (n = 5) differs by scale counts of V♂ = 190–201 (181), SC♂ = 93–100 (105), SCR♂ = 0.32–0.34 (0.37), SLE = 3+4 (3+4+5), and ILG = 5 (4) Additional differences include (1) the rostral of S. melanolabiatus is barely visible on the dorsal surface of the head, where it forms a gull wing when viewed from above (gull wing +); (2) InS = PfS (InS = 2⁄3 PfS); (3) AE lies at the same level as the anterior end of the frontal (AE lies behind anterior edge of the frontal); (4) the lateral ray of AP ( is directed posterolaterally (laterally); and (5) FL = 3⁄4 ParS (FL = ParS). The closest known locality for S. melanolabiatus is at Bobole, Hela Province, PNG (Ruane et al. 2017), ca. 1300 km by air from the type locality of S. ayamaru. Stegonotus modestus (n = 14) differs by scale counts of V♂ = 195–206 (181), SC♂ = 78–94 (105), SCR♂ = 0.28–0.31 (0.37), and SLE = 3+4, rarely 4+5 (3+4+5). Additional differences include (1) InS = PfS (InS = 2⁄3 PfS); (2) AE lies at the same level as the anterior end of the frontal (AE lies behind anterior edge of the frontal); (3) the lateral ray of AP ( is directed posterolaterally (laterally); (4) FL is slightly shorter than ParS (FL = ParS); and (5) almost all known specimens of S. modestus have a distinctive, incomplete, light-colored band that marks the end of the head (no neck band). The closest known locality for S. modestus is on Seram Island, Maluku Province, Indonesia, ca. 250 km by air from the type locality of S. ayamaru. Stegonotus muelleri (n = 18) is from the south-central Philippine Islands and differs by scale counts of V♂ = 226–241 (181), D = 19-17-15 (17-17-15), SC♂ = 85–108, SCR♂ = 0.26–0.31 (0.37), SLE = 4+5 (3+4+5), SL = 8, or rarely 9 (7), and IL = 10, or rarely 9 (8). Additional differences include (1) InS = PfS (InS = 2⁄3 PfS); (2) the lateral ray of AP ( is directed posterolaterally (laterally); and (3) FL = ParS (FL = ParS). The closest known locality for S. muelleri is on the Philippine island of Mindanao, ca. 1200 km by air from the type locality of S. ayamaru. Stegonotus parvus (n = 1; numeric data are from the original species description7, specimen destroyed) differs by scale counts of V♂ = 177 (181), SC♂ = 100 (105), and SLE = 3+4 (3+4+5). Additional differences include (1) the rostral of S. parvus is not visible on the dorsal surface of the head (gull wing +); (2) InS = PfS (InS = 2⁄3 PfS); (3) the lateral ray of AP ( is directed posterolaterally (laterally); (4) FL = ParS (FL = ParS); (5) PF ( < 90° (≥ 90°); and (6) four neck scales contact the parietals (3). The closest known locality for S. parvus is on Yapen Island, Papua Province, Indonesia, ca. 400 km by air from the type locality of S. ayamaru. Stegonotus poechi (n = 1, a female specimen) differs by scale counts of V♀ = 200 (181), D = 19-19-17 (17-17- 15), SLE = 4+5+6 (3+4+5), SL = 9 (7), and IL = 10 (8). Additional differences include (1) the rostral of S. poechi is clearly visible on the dorsal surface of the head, where it forms a U (Fig. 3F) when viewed from above (gull wing +); (2) the rostral intrudes upon the internasal space, somewhat shortening the internasal suture (does not extend into internasal space, internasal suture not impacted); (3) InS = 1⁄2 PfS (InS = 2⁄3 PfS); (4) the lateral ray of AP ( directed posterolaterally (laterally); and (5) PF ( < 90° (≥ 90). The closest known locality for S. poechi is in Madang Province, PNG, ca. 4.2280°S, 144.9333°E (see Kaiser et al. 2018a), ca. 1400 km by air from the type locality of S. ayamaru. Stegonotus reticulatus (n = 82) differs in counts of V♂ = 188–230 (181), SC♂ = 71–92 (105), SCR♂ = 0.26–0.33 (0.37), SLE = 4+5, rarely 3+4 (3+4+5), SL = 8 or 9, or rarely 7 (7), and IL = 9 or 10 (8). Additional differences include (1) InS = PfS (InS = 2⁄3 PfS); (2) AE lies at the same level as the anterior end of the frontal (AE lies behind anterior edge of the frontal); (3) FL is slightly shorter than ParS (FL = ParS); (4) two temporals contact the parietals (3); and (5) there is a very prominent color pattern in S. reticulatus, where each dorsal scale has dark posterior edging to produce a reticulated pattern (no distinctive color pattern). The closest known locality for S. reticulatus is along the Ok Ma Road in Western Province, PNG, ca. 1100 km by air from the type locality of S. ayamaru. We have also examined a specimen (USNM 119549) from the Padaido Islands, Papua Province, Indonesia (ca. 500 km by air from the type locality of S. ayamaru), whose color pattern approximates that of S. reticulatus. With all other specimens of S. reticulatus occurring in localities south of New Guinea’s mountainous spine or along its southern versant, we set this specimen aside for further examination as S. cf. reticulatus. Stegonotus sutteri (n = 2) differs in counts of V♂ = 210–230 (181), D = 21-21-19 (17-17-15), SC♂ = 83 unpaired (105, paired), SCR♂ = 0.27 (0.37), SL = 9 (7), and IL = 9 or 10 (8). Additional differences include (1) the rostral of S. sutteri is barely visible on the dorsal surface of the head, where it forms a gull wing when viewed from above (gull wing +); (2) InS = 1⁄2 PfS (InS = 2⁄3 PfS); (3) the lateral ray of AP ( is directed posterolaterally (laterally); and (4) FL = ParS (FL = ParS). The closest known locality for S. sutteri is on Sumba Island, ca. 1600 km by air from the type locality of S. ayamaru. |
| Comment | Habitat: lowland primary rainforest Only known from the holotype. |
| Etymology | The species name ayamaru is a noun in apposition. It references the Ayamaru people of Maybrat Regency, West Papua, Indonesian New Guinea and their homonymic language. Kaiser et al. 2019 selected this name not only to indicate the type locality but also to highlight the Ayamaru people’s struggle to protect their forests and waterways from exploitation. The Ayamaru Lakes are a case in point. One of the several endemic fishes in the lake (Melanotaenia boesemani) has been over-collected and is currently listed as Endangered on the IUCN Red List (Allen 1996). West Papua was recently declared a conservation province (Anonymous 2018), and it is hoped that this will have a long-term, positive effect on regional development. |
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