Helicops acangussu MORAES-DA-SILVA, WALTERMAN, CITELI, SALES-NUNES & CURCIO, 2022
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Helicops acangussu
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| Higher Taxa | Colubridae (Dipsadinae), Colubroidea, Caenophidia, Alethinophidia, Serpentes, Squamata (snakes) |
| Subspecies | |
| Common Names | |
| Synonym | Helicops acangussu MORAES-DA-SILVA, WALTERMAN, CITELI, SALES-NUNES & CURCIO 2022 |
| Distribution | Brazil (Rondonia) Type locality: Brazil, Rondonia, Porto Velho municipality, left bank of the upper Madeira River (9°2'56.03"S, 64°18'17.70"W), 86 m elevation. |
| Reproduction | oviparous |
| Types | Holotype: UFRO-R 2748, adult female, unknown collector, on 23 September 2009; Paratypes (n = 27): MPEG, UFRO-R |
| Diagnosis | Diagnosis: “Helicops acangussu sp. nov. differs from all congeners by the following unique combination of characters: (1) dorsals 19–21/19/17–18 with moderate dorsal keels throughout the whole body length; (2) ventrals 121–129 (121–128 in males, 124–129 in females); (3) subcaudals 40–67 (52–67 in males, 40–43 in females); (4) subcaudal keels absent; (5) supralabials 8/8, 4th with orbit; (6) infralabials 10/10; (7) intergenials separating the 2nd pair of genials; (8) nasal semidivided; (9) one preocular; (10) two postoculars; (11) maxillary teeth 16–18 + 2; (12) hemipenis semicapitated, lobes asymmetrical (one of the lobes distinctly longer its counterpart), with medium-sized spines dispersed on lateral surface of body; (13) snout exhibiting a triangular light spot (light tan in life) usually covering the rostral, internasals, prefrontals, and anterior borders of frontal and supraoculars; (14) dorsum greenish grey, with five rows of black rounded spots, smaller on flanks and increasing in size towards vertebral level; (15) 35–47 dorsal spots on trunk (35–47 in males, 36–42 in females), and 10–23 dorsal spots on tail (13–23 in males, 10–15 in females); (16) venter background yellowish cream, checkered with asymmetrical black squared blotches, mostly divided at midline with their halves alternately displaced in opposite directions, and (17) 37–52 black bands on venter (37–52 in males, 38–44 in females), and 10–20 black bands on tail (13–20 in males, 10–14 in females).” (Moraes-da-Silva et al. 2022). Comparisons: “Helicops acangussu sp. nov. is distinguishable from 11 out of the 20 congeners by having small and rounded black spots on dorsum (vs. saddles, in H. angulatus, H. apiaka, H. cyclops, and H. gomesi; stripes, in H. carinicaudus, H. infrataeniatus, H. modestus, and H. trivittatus; irregular bands, in H. phantasma, and uniform, in H. nentur and H. tapajonicus). That leaves nine nominal taxa with rounded dorsal spots or blotches (H. boitata, H. danieli, H. hagmanni, H. leopardinus, H. pastazae, H. petersi, H. polylepis, H. scalaris and H. yacu), which distinction from the new species must rely on other character sources. Dorsal counts of 19 scale rows at midbody distinguish Helicops acangussu sp. nov. at least from H. boitata (25), H. hagmanni (23–27), H. pastazae (21–23), H. petersi (21–23), H. polylepis (22–25), and H. yacu (25–28). Among the species sharing the same number of dorsals (H. danieli, H. leopardinus, and H. scalaris), H. acangussu sp. nov. is readily recognisable by the presence of intergenials (absent in H. danieli and H. leopardinus) and absence of subcaudal keels (present in H. scalaris). In addition, the moderate dorsal keels of the H. acangussu sp. nov. differ unequivocally from the strong keels of H. hagmanni, H. pastazae, H. petersi, H. polylepis, and H. scalaris. Regarding infralabial counts, H. acangussu sp. nov. (10 scales) appears to differ from H. boitata (12–13), H. petersi (8), H. polylepis (11–13), H. scalaris (8–9), and H. yacu (11–12). Helicops acangussu sp. nov. is distinguishable from 11 out of the 20 congeners by having small and rounded black spots on dorsum (vs. saddles, in H. angulatus, H. apiaka, H. cyclops, and H. gomesi; stripes, in H. carinicaudus, H. infrataeniatus, H. modestus, and H. trivittatus; irregular bands, in H. phantasma, and uniform, in H. nentur and H. tapajonicus). That leaves nine nominal taxa with rounded dorsal spots or blotches (H. boitata, H. danieli, H. hagmanni, H. leopardinus, H. pastazae, H. petersi, H. polylepis, H. scalaris and H. yacu), which distinction from the new species must rely on other character sources. Dorsal counts of 19 scale rows at midbody distinguish Helicops acangussu sp. nov. at least from H. boitata (25), H. hagmanni (23–27), H. pastazae (21–23), H. petersi (21–23), H. polylepis (22–25), and H. yacu (25–28). Among the species sharing the same number of dorsals (H. danieli, H. leopardinus, and H. scalaris), H. acangussu sp. nov. is readily recognisable by the presence of intergenials (absent in H. danieli and H. leopardinus) and absence of subcaudal keels (present in H. scalaris). In addition, the moderate dorsal keels of the H. acangussu sp. nov. differ unequivocally from the strong keels of H. hagmanni, H. pastazae, H. petersi, H. polylepis, and H. scalaris. Regarding infralabial counts, H. acangussu sp. nov. (10 scales) appears to differ from H. boitata (12–13), H. petersi (8), H. polylepis (11–13), H. scalaris (8–9), and H. yacu (11–12).” Color in life: “One adult specimen photographed in life exhibited a yellowish light green dorsum background, and the black spots exhibited a non-uniform distribution of black pigment; the snout exhibited a light tan and roughly triangular spot; belly ornament by irregular bands in checkered format.” (Moraes-da-Silva et al. 2022). |
| Comment | Similar species: Helicops hagmanni, H. leopardinus, and H. polylepis. |
| Etymology | The specific epithet is a noun in apposition derived from the Tupi-Guarani (akãgu’su; a’kãga meaning “head”, u’su meaning “large”), a vernacular designation to the Jaguar [Panthera onca (Linnaeus, 1758)], a spotted South American big cat. Herein, it represents an allusion to the spotted pattern of the new species, as well as to the aggressive behaviour of most Helicops species that promptly bite when disturbed. |
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