After reading the paper, these are the most important features to distinguish P. cupressina and P. vulgaris (considered distinct species).


Spore Size (at maturity)
Pithya cupressina: (9) 10-12 (12.5) um
Pithya vulgaris 12-15 um

Substrate Specialization 
Pithya cupressina: Cupressaceae (e.g., Chamaecyparis, Cupressus, Juniperus, Sequoia, Thuja)
Pithya vulgaris: Pinaceae (usually Abies species, occasionally Picea, Pinus)

Size of Apothecia
Pithya cupressina: 2-5 mm wide
Pithya vulgaris: (5-) 10-15 mm wide

My finding was on an unkown twig up to 5.5mm wide and spores with the following measurments:  

9.1 [10.1 ; 10.6] 11.6 × 8.9 [9.9 ; 10.4] 11.3 µm
Q = 1 [1.0] 1.1 ; N = 27 ; C = 95%
Me = 10.4 × 10.1 µm ; Qe = 1



So it is (disappointingly) the usual Pithya cupressina which grew slightly larger up to 5mm possibly because they were growing on a woody twig, while on leaves and leaf petioles  fruiting bodies only reach  1-3mm in diameter (here in Malta). 

Eye-catching are the operculate asci !!!