Paroplocephalus

Bush, Brian, 2017, Additions to the description of Paroplocephalus atriceps (Serpentes: Elapidae) with a discussion on pupil shape in it and other Australian snakes, Zootaxa 4344 (2), pp. 333-344 : 334-335

Paroplocephalus description updated with additional data

AdditiOnS tO the deScriptiOn Of Paroplocephalus are required here tO clarify pupil Shape and tO enlarge On the mOrphOmetricS cOntributed tO by the additiOnal 12 SpecimenS available fOr examinatiOn during thiS Study. The fOllOwing diagnOSiS iS reprOduced (with permiSSiOn) frOm KeOgh et al. (2000) with amendmentS and additiOnS frOm thiS Study inSerted.

Diagnosis. A mOnOtypic genuS cOntaining P. atriceps , a terreStrial hydrOphiine elapid Snake with anal and all SubcaudalS undivided; dOrSal ScaleS SmOOth but nOt highly glOSSed; head mOderately brOad and diStinct frOm neck; eye large, pupil rOund; 3 nOncanaliculate maxillary teeth behind diaStema; tempOral ScaleS 2 + 2 + 3 (N 7), 2 + 2 + 4 (N 8), 2 + 3 + 4 (N 1) and 2 + 3 + 5 (N 1) (fOrmula fOllOwS definitiOn in ScanlOn, 2000); preOcular withOut canthuS rOStraliS, cOntactS undivided naSal and 2nd Supralabial; 6 SupralabialS (41%), Or 7 (59%) when tempOrOlabial (lOwer anteriOr tempOral) reacheS lip between 5th and laSt; parietal Separated frOm lOwer pOStOcular; 7 infralabialS. ‘ Oxyuranu S type’ Of venOm-gland muSculature (sensu McDOwell, 1967; main dOrSal pOrtiOn Of m. adductor externus medialis reaching tranSverSe creSt Of SupraOccipital and Overlapping anteriOr part Of m. depressor mandibulae, but nOt attaching tO quadrate). Neck and pOSteriOr trunk Slender, and bOdy SOmewhat laterally cOmpreSSed; ventral ScaleS extend tO lOwer lateral Surface Of bOdy, and their pOSteriOr edgeS arcuate (lateral partS cOncave; See Ehmann, 1993). Scale rOwS 21–23 at firSt ventral, SOmetimeS reducing tO 17 On neck, 17 (N 2) Or 19 (N 15) at midbOdy; twO Or three reductiOnS, (17–15–13) Or (19–17–15–13) reSpectively pOSteriOr tO midbOdy, SOmetimeS increaSing again tO 15 rOwS at Or juSt befOre laSt ventral. VentralS 171–190 (N 17, mean 180), maleS 171–183 (N 12, mean 178.1), femaleS 180–190 (N 5, mean 184.8). SubcaudalS 41–52 (N 17, mean 47), maleS 44–52 (N 12, mean 48.1), femaleS 40–48 (N 5, mean 42.8). Upper iriS pale, reducing tO a narrOw pale band bOrdering remainder Of pupil (gOlden Orange in life: StOrr, [1980] – See Figure 1B thiS Study); bOdy reddiSh brOwn, Olive green (in eaStern part Of range), Or blackiSh brOwn; head dull black Or dark grey with pale SpOtS On upper and lOwer labialS, and denSer black cOllar On neck, pale-edged pOSteriOrly; dOrSal bandS Or blOtcheS abSent ( Figure 7 ); Oral lining pale, tOngue dark. LargeSt live Specimen iS a female (currently kept at SnakeS Harmful & HarmleSS) with SnOut-vent length (SVL) 730 mm, undamaged tail length 90 mm (12.3% SVL vS. 16.1% in WAM R132047, a female examined by KeOgh et al. 2000); the largeSt male (WAM R 151290) haS SVL 530 mm, tail 99 mm (18.7%). PreSumed tO be viviparOuS, but reprOductiOn and natural diet unknOwn apart frOm a Single prey recOrd Of an agamid lizard.

MOSt like Hoplocephalus Spp. in bOdy fOrm and ScalatiOn (alSO cranial mOrphOlOgy, KeOgh et al. 2000); diStinguiShed by lOwer number Of ventralS (171–190 vS. 190–250) and uSually Of SubcaudalS (41–52 vS 40–70), lOwer number Of midbOdy Scale rOwS (17–19 vS 19–21), Only weakly angled and ScallOped ventral ScaleS (vS uSually diStinctly keeled and nOtched aS an adaptatiOn fOr climbing). DiStributiOn reStricted tO arid eucalypt wOOdlandS Of WeStern AuStralia ( Figure 2 ) v eaSt cOaSt, hinterland and arid eucalypt wOOdlandS Of New SOuth WaleS and QueenSland.

Figures

FIGURE 1. A, eye of preserved Paroplocephalus atriceps (R 151290) showIng the effect of ethanol on IrIs and pupIl colour. In lIfe, the IrIs has a large upper flare of golden-yellow that has gone altogether and the pupIl has been changed from black to whIte. In some preserved IndIvIduals, the pupIl Is IndIscernIble from the IrIs altogether. B, eye of Paroplocephalus atriceps showIng round pupIl wIth slIght apIcal bulge. DurIng dIlatIon and constrIctIon pupIl eXpands or reduces equIdIstantly from Its centre maIntaInIng a round shape. C, eye of Suta fasciata showIng a rough-edged round pupIl, whIle the IndIvIdual In D has a smooth-edged round pupIl although In some lIterature It Is descrIbed as vertIcally ellIptIc. DurIng dIlatIon and constrIctIon pupIl eXpands or reduces equIdIstantly from Its centre maIntaInIng a round shape and any blemIshes around Its cIrcumference. E, eye of Echiopsis curta showIng round pupIl, although In some lIterature It Is descrIbed as vertIcally ellIptIc. DurIng dIlatIon and constrIctIon pupIl eXpands or reduces equIdIstantly from Its centre maIntaInIng a round shape. (Photo by B. Maryan). F, eye of Acanthophis pyrrhus showIng narrow vertIcally ellIptIc pupIl. DurIng dIlatIon and constrIctIon pupIl eXpands or narrows laterally.

FIGURE 2. Map of AustralIa showIng the known dIstrIbutIon of Paroplocephalus atriceps In Western AustralIa. The easterly dot represents the Fraser Range records.

FIGURE 7. Paroplocephalus atriceps showIng domInant brown dorsal colour In western populatIon and green In eastern populatIon. Bottom photo by S Thompson.