Diagnosis (based on the type series; osteology based on micro-CT scan of ZSM 618/2009, male): Calumma emelinae sp. nov. is characterised by (1) a medium size (male SVL 46.6 – 48.7 mm, female SVL 40.1 – 49.1 mm; male TL 93.6–103.2 mm, female TL 82.7–95.8 mm), (2) a medium (2.3–2.9 mm in males 1.5–1.8 mm in females) and distally rounded rostral appendage, (3) rostral scale not integrated into the rostral appendage, (4) rostral crest present, (5) lateral crest present, (6) temporal crest present, (7) cranial crest variable, (8) parietal crest usually absent, (9) casque low in males with a height of 0.5 – 1.1 mm, (10) a dorsal crest of 7 – 10 spines in males, absent in females, (11) 12–16 supralabial scales with a mostly straight upper margin, serrated anteriorly, (12) absence of axillary pits, (13) diameter of the largest scale in the temporal region of the head 0.6–1.0 mm, (14) no frontoparietal fenestra, (15) parietal and squamosal in contact, (16) parietal bone width at midpoint 16.2% of skull length (n=1), (17) a generally greyish to greenish body colouration, (18) rostral appendage colour generally unremarkable, (19) a green cheek colouration, (20) suggestions of two weak bluish lateral blotches, and (21) no strong eye colouration.
Calumma emelinae sp. nov. can easily be distinguished from all species of the C. boettgeri complex (see above) by the absence of occipital lobes; from C. gallus by different length, shape and colour of its rostral appendage (see above); from C. vatosoa by presence of a rostral appendage (vs absence); from C. vohibola by generally longer relative rostral appendage length (RRS 3.1–6.1% vs 0.1–1.4%), dorsal crest always present in males (vs generally absent), and pointed tip of postparietal process (vs relatively broad), and crenate prefrontal (vs smooth); from C. nasutum as redefined herein by a lower casque in males (0.5 – 1.1 mm vs 1.5 – 2.0 mm), dorsal crest present in males consisting of spines (vs general absence or consisting of cones if present), and scales more homogeneous (largest temporal scale in males 0.7 mm vs 0.9 – 1.6 mm); from C. radamanus by relatively longer tail in males (longer than SVL vs shorter), longer rostral appendage in males (RRS 4.7 – 6.1% vs 2.9 – 3.6%), rostral scale not integrated into rostral appendage (vs integrated), supralabials with a largely straight upper margin (vs serrated), and parietal and squamosal in contact (vs widely separated); for diagnosis against C. fallax, see below. For diagnosis against the other species described herein, see their respective descriptions below.