1933 illustration based on the male holotype specimen. Note the blue colouration, as it was unknown that the preservation process of the specimen had changed its colour from bright green to blue.
Once only known from the holotype, a single specimen collected from North Sumatra in 1891, the species was rediscovered after a living population of the species was sighted in 2018.[3]
The holotype specimen is a male, and the preservation process had caused it to turn blue. The discovery of live specimens in 2018 revealed that the species is naturally a luminous green colour in life.[3]
H. modiglianii has a sickle-shaped upturned nasal appendage. Not including this appendage, the holotype has a snout-to-vent length (SVL) of 8.3 cm (3.3 in), and a tail length of 13.9 cm (5.5 in). Its nasal appendage is 6 mm (0.24 in) long, roughly as long as the head.[5]
Putra CA, Amarasinghe AAT, Hikmatullah D, Scali S, Brinkman J, Manthey U, Ineich I (2020). "Rediscovery of Modigliani's nose-horned lizard Harpesaurus modiglianii Vinciguerra, 1933 (Reptilia: Agamidae) after 129 years without any observation". Taprobanica9 (1): 3–11 + Plates 1–3.
Vinciguerra D (1933). "Descrizione di una nuova specie di Harpesaurus di Sumatra". Annali del Museo Civico di Storia Naturale Giacomo Doria56: 355–357. (Harpesaurus modiglianii, new species). (in Italian).