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Neelaps calonotos (Duméril, Bibron & Duméril, 1854) Black-striped Burrowing Snake

Lectotype. MNHN-RA-2012.411 (formerly 3943A), male, the larger of the two syntypes, designated by Wells & Wellington (1985: 46), original type locality “Tasmanie” [= Tasmania, Australia] in error, restricted to Perth, Western Australia, fide Storr (1968: 85), obtained from J.P. Verreaux and received in Paris, France in 1844 (G. Shea, pers. comm.).

Paralectotype. MNHN-RA-0.3943, male, same details as lectotype.

Furina calonotos Duméril, Bibron & Duméril 1854a, Erpétologie Générale ou Histoire Naturelle Complete des Reptiles, Tome séptieme: 1241.

Furina calonotus Duméril, Bibron & Duméril 1854b, Erpétologie Générale ou Histoire Naturelle Complete des Reptiles, Tome neuvième: 377.

Brachysoma calonotos Günther 1858, Catalogue of Colubrine Snakes in the collection of the British Museum: 229.

Neelaps calonotus Günther 1863, Annals and Magazine of Natural History: 24.

Pseudelaps calonotus Jan 1863, Elenco sistematico degli ofidi descritti e disegnati per l’Iconografia Générale: 116.

Neelaps caledonicus Hoffman 1890, Klassen und Ordnungen des Their-Reichs, wissenshaftlich dargestellt in Wort und Bild: 1788. In error for calonotus.

Furina calonota Boulenger 1896, Catalogue of the Snakes in the British Museum (Natural History), Vol III: 407.

Neelaps neocaledonicus Palacky 1898, Mémoires de la Société Zoologique de France: 121. In error for caledonicus.

Vermicella calonota Glauert 1950, A Handbook of the Snakes of Western Australia: 38.

Melwardia calonota Worrell 1960, Western Australian Naturalist: 132.

Vermicella calonotos Storr 1968, Journal of the Royal Society of Western Australia: 85.

Simoselaps calonota Underwood 1979, Classification and Distribution of Venomous Snakes in the World: 32.

Simoselaps calonotus Cogger 1992, Reptiles & Amphibians of Australia: 684.

Neelaps calonotos Storr, Smith & Johnstone 2002, Snakes of Western Australia Revised Edition: 191.

Vermicella calonotus Wallach, Williams & Boundy 2014, Snakes of the World A Catalogue of Living and Extinct Species: 771.

Confusion regarding spelling of name and the type specimens. The original description in Volume 7 of Duméril, Bibron & Duméril (May 1854a: 1241) is under the name Furina calonotos (as also used, as a nomen nudum, by Duméril (1853: 517) in a Prodromus to the classification of snakes to be used in 1854). However, in Volume 9 the same authors (September 1854b: 377), in a summary of the entire 9 volumes of the Erpétologie Générale, provide a brief redescription under the name Furina calonotus. Obviously not aware of this, Cogger et al. (1983: 228) incorrectly stated that the species name calonotos was validly emended to calonotus by Günther (1863: 24); see also remarks by Wallach et al. 2014: 771. However, neither Duméril et al. (1854b) nor Günther (1863) provided any explanation as to why the species name should change. Hence, under the Code, the change must be considered an incorrect subsequent spelling rather than either a justified or unjustified emendation (an emendation requires a statement that the change has been made; Article 33.2.1 of the Code of Zoological Nomenclature).

David & Ineich (1999: 189) note that the original epithet calonotos (“beautiful back”) is a Greek name in apposition, not an adjective, and consider the change to calonotus an incorrect subsequent spelling, a conclusion with which we agree. However, under Article 33.3.1 of the Code, when an incorrect subsequent spelling is in prevailing usage and is attributed to the publication of the original spelling, the subsequent spelling is deemed to be a correct original spelling, and is to be maintained. The Code further defines “prevailing usage” as “that usage of the name which is adopted by at least a substantial majority of the more recent authors concerned with the relevant taxon, irrespective of how long ago their work was published”. Based on the literature used here, the spelling calonotos (e.g. Storr et al. 1978: 196; Clarke & How 1995: 69; Strahan et al. 1998: 57; How & Shine 1999: 269; How & Dell 2000: 202; Storr et al. 2002: 191; Bush et al. 2007: 254, 2010: 149; He 2021: 85; Wilson & Swan 2021: 614; Eipper & Eipper 2022: 96) has been used with similar frequency to calonotus (e.g. Shine 1984: 173; Ehmann & Cogger 1985: 443; Wilson & Knowles 1988: 338; Kennedy 1990: 108; Ehmann 1992: 452; Cogger et al. 1993: 164; Greer 1997: 182; Reed & Shine 2002: 454; Cogger 2014: 904; Allen & Vogel 2019: 93‒94; Chapple et al. 2019: 519) without either name having achieved usage over the other. Further, the majority of specimens (86%) are held by the WAM under calonotos, hence we argue the original spelling calonotos should be maintained. As calonotos is a noun, it does not change gender in combination with differing generic names, and hence the spelling calonota, used in combination with Furina (Boulenger 1896: 407), Vermicella (Glauert 1950: 38), and Melwardia (Worrell 1960: 132) is also incorrect.

Similarly, there are confusing accounts for the type specimens. Cogger et al. (1983: 228) lists 2 specimens as syntypes under a single MNHP (= MNHN) number 3943, and The Reptile Database (Uetz et al. 2021) lists two specimens MNHN 3943 and 3943A as paralectotypes, even though there is only one lectotype and one paralectotype. In the original description it clearly states that there are two specimens of F. calonotos with separate colour descriptions provided for each specimen (Duméril, Bibron & Duméril 1854a: 1241). A lectotype designation was made by Wells & Wellington (1985: 46) as “MNHP 3943, being the larger of the two syntypes registered under this number”, apparently without examining the specimens. They presumably based their statement of two syntypes under the number 3943 from the listing by Cogger et al. (1983), without realising that the two specimens are independently numbered 3943 and 3943A in the MNHN collection. Hence, it is not clear whether the lectotype is MNHN 3943 (the only specimen actually under that number), or the larger of the two specimens MNHN 3943 or MNHN 3943A. Wallach et al. (2014: 771) list MNHN 3943A as lectotype “being the larger of the two syntypes”, following Wells & Wellington (1985), but provide no measurements to support this determination. Designation of a lectotype without having examined it is an unfortunate legacy of Wells & Wellington publications that will continue to cause issues for future researchers (see Dong et al. 2021). Fortunately in this case, we received total length measurements from Paris (J. Courtois, pers. comm.) of 250 mm for MNHN 3943 and 252 mm for MNHN 3943A (now catalogued 2012.411, Fig. 4B), confirming the latter specimen is the larger of the two syntypes, so we maintain the application of MNHN 2012.411 as lectotype and MNHN 3943 as paralectotype in accordance with the Muséum National d’Histoire Naturelle database:


Figure 7. Adult Neelaps calonotos photographed in life from (A) Casuarina, Western Australia, (B) 5 km SSE of Port Denison, Western Australia, WAM R141838, (C) Ellenbrook, Western Australia, and (D) Ballajura, Western Australia, showing the variation in body colour and the typically complete vertebral stripe of varying width, occasionally reduced or absent as in Figs. 7C, D (photos‒B. Maryan).

Description of lectotype (Fig. 4B). Scalation and proportions as in the diagnosis for the genus. Individual characteristics include: internasals and prefrontals much wider than long with medial suture much offline so that right internasal contacts left prefrontal; single preocular, slightly higher than wide, in contact with nasal; two postoculars, the upper much larger; frontal much wider anteriorly, gradually narrowing to rounded point between parietals; parietals equal size; temporal above sixth supralabial contacting both postoculars; six supralabials, first and second smallest, third higher in contact with orbit, fourth under orbit in contact with lower postocular, fifth in contact with lower postocular and temporal, sixth much the largest; mental triangular with undulating anterior edge (possibly caused by preservation) between first infralabials; seven infralabials; anterior chin shields in broad contact with infralabials one to three; posterior chin shields in broad contact with fourth infralabials only; six rows of intergulars between chin shields and anterior most broad ventral.

After ≥ 167 years in preservative (Fig. 4B), the lectotype has faded to white on the dorsolateral surface (discoloured where epidermis remains attached), including interspaces behind tip of snout and head band, extending onto anterior portion of supraoculars, with complete narrow black vertebral stripe one scale wide extending from nape to tip of tail (reducing to zig-zag line along tail), each scale within stripe enclosing a white anterior spot, gradually decreasing in size distally to vanishing along tail. Tip of snout and head and nape bands remain black.

Colour in life and in preservative. The following description of colour in life is based on Figs. 7A, B, C, D, and field observations of N. calonotos in Western Australia. The descriptions in preservative and of variation are based on all specimens of N. calonotos listed in the Appendix.

In most colour descriptions for N. calonotos authors mention a cream or white centre on each body scale including those within the dark vertebral stripe (e.g. Storr et al. 2002; Bush et al. 2010; Wilson & Swan 2021). After our examination of photos in live individuals (Figs. 7A, B, C, D) and close inspection of the body scales in the specimens (see Appendix) under a microscope, we observed the pale pigment is concentrated more on the anterior portion (= basal, see Scanlon 1985: 51) of each scale and varied in development from a spot to covering up to ¾ of the scale.

In life, variable body colour of bright red (Fig. 7A), pale pinkish red (Fig. 7B) or orange red (Figs. 7C, D), with paler or similar colored interspace between dark bands, and more cream to white between dark tip of snout and band on head, each body scale enclosing a yellowish, cream or white anterior portion or spot (covering up to ¾ of scale), with dark pigment on the body scales consisting of a typically distinct black vertebral stripe 1‒3 scales wide extending from nape to tip of tail (Figs. 7A, B), often broader posteriorly and then reducing to a zig-zag line on tail. Stripe encloses bright cream or white anterior portion or spot on vertebrals forming a chain-like pattern, often gradually decreasing in size distally and vanishing on tail. Dark stripe, varying in development from clearly broad and complete (Fig. 7A) or narrow (Fig. 7B), or occasionally reduced and largely broken, although some indications remain on posterior body or tail (Fig. 7C) and rarely unstriped (Fig. 7D). Black tip on the snout consistently present, variously covering rostral and not extending on to ventral edge, extending back to partially cover or just to edge of internasals, and lateral edge narrowly covering nasals, occasionally extending back to nostrils. Black band on head commencing on or just before anterior edge of frontal and just forward of eyes, extending back partially or narrowly covering supralabials four to six, occasionally supralabials without dark pigment (Fig. 7C), and ending slightly behind posterior edge of parietals to partially or completely cover first vertebral. Black band on nape crescent-shaped and 2½‒5 scales long, separated from head band by 2‒3 vertebral scales, occasionally with cream or white anterior portion or spot on scales at rear of band. Eyes are black without discernible pupils. Ventral surface under the head and along the body, including the lateroventral edges is cream white to pale yellow with glossy shine.

In preservative, body colour fades to white including interspaces on the head. Dark head and nape bands, tips on snouts and vertebral stripes when present along the body faded to brown but overall retained a black appearance, even in very old specimens (e.g. MNHN-RA-0.3943, MNHN-RA-2012.411). The white ventral surface remains glossy.

Variation includes: development of vertebral stripe from typically broad or narrow and complete up to 3 scales wide, or reduced and largely broken with some indications remaining on posterior body or tail to complete absence. To quantify this intraspecific variation, we examined 93 WAM specimens of N. calonotos (including listed in the Appendix), recording the typical condition of a distinct vertebral stripe in 75% of specimens including the lectotype and paralectotype. The next recorded condition of a faint and largely broken stripe was present in 20% of specimens. Only four specimens have the rare unstriped condition. One specimen (WAM R62170, same individual illustrated in Storr et al. 2002: 130) has a very broad vertebral stripe extending on to adjacent margins of fourth scale on either side. The pale anterior portion or spot on each body scale within the stripe remain distinct. The dark head band displays varying levels of coverage on some scales such as the frontal, supraoculars and supralabials. The dark tip on the snout is reduced in one specimen (WAM R152960) extending back to very narrow edge of internasals and upper portion of nasals well separated from nostrils.

Measurements, counts, and scalation. Table 2 presents the minimum‒maximum range, means, and standard deviations of the characters measured and counted (as defined in Table 1) for each sex and all adult specimens of N. calonotos listed in the Appendix. Sexual dimorphism is pronounced, where females have shorter tails than males (as found previously by Clarke & How 1995), fewer subcaudal scales, yet higher number of ventral and vertebral scales (Table 2).

The head scale configuration in N. calonotos display minimal intraspecific variation. For illustration of head scalation in N. calonotos, see Storr et al. (2002: 191). All the specimens have the nasal contacting the preocular, except in one specimen (WAM R97886) in which these scales are separated by the prefrontal on both sides. One specimen (WAM R127530) has the second supralabial contacting the preocular on the left side; another specimen (WAM R25065) has narrow contact between preocular and frontal on both sides. Storr (1968: 85) recorded the typical condition of the upper primary and secondary temporals fused to form a single elongate scale in 80% of specimens. We observed the same typical condition in all specimens on both sides, albeit in a comparatively smaller sample size (see Appendix), except in one specimen: WAM R87906 has 1 primary + 1 secondary temporals on both sides.

Other variations of scalation include: two specimens (SAMA R29765, WAM R40287) have five supralabials on the right side, caused by fusion between first and second supralabials; SAMA R29765 also has fused postoculars on the left side forming a single scale; WAM R40287 has the fourth supralabial on the right side contacting the upper postocular bisecting lower postocular and temporal; one specimen (WAM R25065) has one postocular on the left side caused by fusion of lower with fourth supralabial; and a specimen (WAM R62158) has three postoculars on the left side caused by a divided lower postocular.

Figure 7. Adult Neelaps calonotos photographed in life from (A) Casuarina, Western Australia, (B) 5 km SSE of Port Denison, Western Australia, WAM R141838, (C) Ellenbrook, Western Australia, and (D) Ballajura, Western Australia, showing the variation in body colour and the typically complete vertebral stripe of varying width, occasionally reduced or absent as in Figs. 7C, D (photos‒B. Maryan).

Distribution. Essentially unchanged from species maps of Storr et al. (2002: 191) and Bush et al. (2010: 149), N. calonotos is endemic and restricted to the temperate Swan Coastal Plain and a small area of the Geraldton Sandplains bioregions of southwestern Western Australia (Fig. 6B). On the Swan Coastal Plain, extends north to 15 km NNE of Lancelin and Cooljarloo at 10 km WNW of Walyering Hill, east to Boonanarring Nature Reserve, Muchea, Maralla Road Nature Reserve at Ellenbrook and Forrestdale Lake Nature Reserve (B. Maryan & G. Gaikhorst, pers. obs.), and south to Singleton, Madora and Dawesville (He 2021) near Mandurah. There are disjunct populations on the Geraldton Sandplains bioregion, represented by two specimens (WAM R127530, WAM R141838) from near Port Denison and field observations from Arrowsmith and 8 km S of Eneabba (M. Bamford, pers. comm.; Ecologia Environment 2008; Fig. 6B).

Two specimens (WAM R3827, WAM R7330) from Bickley and York respectively, the latter mapped by Ehmann (1992: 452) and Storr et al. (2002: 191), occur inland from the main coastal plain distribution of this species and require confirmation with additional records (Fig. 6B). Ehmann (1992) noted the York specimen may represent a relictual population isolated by increased aridity in geologically recent times, however the possibility that these distant individuals may have been inadvertently transported to these areas cannot be ruled out.

In general, the occurrence of N. calonotos on and east of the Darling Range in the Jarrah Forest and Avon Wheatbelt bioregions is considered doubtful (Cogger et al. 1993; Bush et al. 2007, 2010; He 2021). Another two more distant specimens (NMV R721, SAMA R2612) with underlying doubt from Katanning and Busselton respectively, are not included on our species map. The Busselton record is possible at the southern extremity of the Swan Coastal Plain bioregion; however it cannot be verified due to an “exchange” entry on the database with no mention of where this specimen was exchanged to (M. Hutchinson, pers. comm.).

Habitat and ecology. Neelaps calonotos is restricted to temperate vegetation that grow on sandy soils, including coastal and near-coastal sand dunes with heaths and/or Acacia thickets, often adjacent to limestone outcropping and dry sclerophyll woodlands of Banksia/Eucalyptus with a shrubland understorey (Wilson & Knowles 1988; Ehmann 1992; Cogger et al. 1993; How & Shine 1999; Bush et al. 2007, 2010; Chapple et al. 2019; Wilson & Swan 2021). The habitats near Port Denison and Eneabba consists of near-coastal sand dunes with low heath and dense thickets of Acacia rostellifera Benth. and open regenerating kwongan heath on white sandy soils with scattered low shrubs and trees (B. Maryan, pers. obs.; Ecologia Environment 2008).

Field observations and collection records (OZCAM 2023) indicate N. calonotos is highly restricted to the sandy soils within the collectively termed claypans of the Swan Coastal Plain Threatened Ecological Community (DPAW 2015). This preference is exemplified by N. calonotos being encountered most frequently in banksia woodland on the Cottesloe sands of the Spearwood Dune formation at Bold Park (How & Shine 1999). Based on the results of recurrent surveys, this species appears to prefer mature banksia woodlands, supported by observations that, in several remnant reserves on the Swan Coastal Plain where historically recorded, it persisted only in the larger, more fire-resistant ones (How & Dell 2000).

In these vegetation associations, N. calonotos, particularly during cooler weather, can be raked from the upper layers of soil or beneath similar configurations of vegetation and debris as described for N. bimaculatus. Field observations of N. calonotos on the surface beneath cover are scarce, apart from one individual found ‘amongst a pile of building rubble in bushland’ (True & Reidy 1981). Like N. bimaculatus, in peak activity N. calonotos can be funnel or pit-trapped or nocturnally observed while driving on roads and tracks (How & Shine 1999; Thompson & Thompson 2007; B. Maryan, pers. obs.). The technique of raking in particular microhabitats can be productive when on occasions up to 5‒7 individuals of N. calonotos can be found in a single day on the Swan Coastal Plain (Maryan 2002; Bush et al. 2007: 33), however it has been extirpated from some remnant bushland areas in recent times by clearing for urbanisation (He 2021; B. Maryan, pers. obs.).

Sympatry with other fossorial species. Broad sympatry, occasionally syntopy, involving N. calonotos occurs on the Swan Coastal Plain and a small area of the Geraldton Sandplains bioregions with B. fasciolatus, B. semifasciatus, N. bimaculatus,and S. bertholdi (Storr et al. 1978; How & Shine 1999; Storr et al. 2002; Maryan 2005; Bush et al. 2007, 2010; B. Maryan, pers. obs.). Where both N. calonotos and N. bimaculatus are known to occur, the trapping data suggests population densities are similar (How & Shine 1999). For instance, during a long-term (> 7 years) herpetofaunal survey at Bold Park, the most abundant taxon S. bertholdi accounted for 122 trapping captures followed by 22 B. semifasciatus, 16 N. calonotos, 10 N. bimaculatus, and 7 B. fasciolatus (How 1998). In contrast, another survey at Maralla Road Bushland of shorter duration (6 months), yielded the same number of captures for N. calonotos and S. bertholdi with comparatively low captures for both Brachyurophis species and N. bimaculatus was not found (Maryan et al. 2002). The disjunct populations on the Geraldton Sandplains bioregion from near Port Denison and Eneabba are also regionally sympatric with S. littoralis (Storr et al. 2002; Maryan 2005).

Comparisons with other fossorial species. Diagnostic differences between N. calonotos and N. bimaculatus are listed under the revised diagnosis for Narophis. Neelaps calonotos will be compared with B. fasciolatus, B. semifasciatus, S. bertholdi, and S. littoralis using Storr et al. (2002) and Wilson & Swan (2021) with which it occurs in sympatry (see above).

It differs from the listed Brachyurophis species in: smaller adult total length to 271 mm (versus to 390 and 353 mm, respectively), lower ventral scale counts of 124‒145 (versus 140‒172 and 147‒188, respectively), typically one elongate temporal scale (versus typically 1 + 1, but often fused in B. semifasciatus), 15 midbody scale rows (versus 17), protrusive round-shaped snout without cutting edge (versus protrusive wedge-shaped snout tipped with transverse weak to strong cutting edge) and typically with vertebral stripe along the body, or if reduced some indications remain (versus cross-banded along the body, but bands ragged-edged in B. fasciolatus).

It differs from the listed Simoselaps species in: smaller adult total length to 271 mm (versus to 300 and 390 mm, respectively), higher ventral scale counts of 124‒145 (versus 112‒131 and 104‒125, respectively), higher subcaudal scale counts of 23‒34 (versus 15‒25 and 16‒23, respectively), typically one elongate temporal scale (versus typically 1 + 1, but primary temporal often large contacting oral margin in S. littoralis) and typically with vertebral stripe along the body, or if reduced some indications remain (versus encircled by bands along the body).

Remarks. Shine (1984), Strahan et al. (1998) and How & Shine (1999) present information on the ecology, reproductive biology, and diet of N. calonotos. Neelaps calonotos has a very restricted distribution and is mostly found on the Swan Coastal Plain between Mandurah and Lancelin (see discussion). Records from further north near Port Denison, Arrowsmith and Eneabba suggest it has a much broader distribution. Systematic or targeted fauna surveys to determine the full distributional extent of N. calonotos on the Swan Coastal Plain and adjoining Geraldton Sandplains bioregions would greatly improve data used to determine conservation status, particularly in poorly surveyed larger conservation reserves such as Yalgorup, Nambung, Lesueur, and Stockyard Gully National Parks.