NEW SUBSPECIES OF RH1NOLOPHUS STHENO 



209 



Table 1 Selected external and craniodental measurements (in mm) of/?, s. microglobosus, R. s. stheno and R. malayanus presented as range, mean ± 

 standard deviation and number of specimens in parentheses. Column 1 : character. Column 2-A: taxon. Column 5-7: Mann-Whitney U Test p-levels 

 between groups. 



Character 



Taxon p-levels between groups 



R. v. microglobosus R. s. stheno R. malayanus R. s. stheno- R. s. stheno- R. s. microglobosus- 



R. s. microglobosus R. malayanus R. malayanus 



FA 



43.8^17.2 



43.6-47.2 



38.3-42.4 







45.46± 1.21 (8) 



45.55± 1.06(21) 



40.45± 1.18(14) 



0.828 



GSL 



18.22-19.38 



18.84-19.92 



17.25-17.79 







18.73±0.35 (10) 



19.37+0.31 (15) 



17.56+ 0.22(1 1) 



0.001 



MTL 



6.74-7.45 



7.25-7.78 



6.54-7.09 







7.05+0.20(12) 



7.49+ 0.15 (16) 



6.75+0.16(11) 



0.001 



ZW 



8.81-9.06 



9.29-9.75 



8.47-8.94 







8.93+ 0.08 (11) 



9.56+0.16 (15) 



8.77+ 0.13 ( 1 1) 



0.000 



MW 



8.71-9.07 



9.09-9.66 



8.14-8.45 







8.87±0.ll (12) 



9.41+0.16(15) 



8.23±0.U (11) 



0.000 



ML 



1 1.83-12.85 



12.59-13.31 



11.18-12.08 







12.23± 0.29 (12) 



12.95+ 0.21 (16) 



ll.79± 0.25(1 1) 



0.000 



LTL 



7.04-7.80 



7.68-8.40 



6.86-7.36 







7.45+ 0.22 (12) 



7.98+ 0. 17 ( 16) 



7. I7± 0.17(11) 



().()()() 



IW 



1.49-1.85 



1 .64 -2.00 



2.13-2.67 







1.66±0.11 (12) 



1.82*0.13 (15) 



2.44± 0. 1 8 ( 1 1 ) 



0.033 



RSW 



4.78-5.07 



5.01-5.38 



4.94-5.37 







4.9I±0.11 (12) 



5.13± 0.10(15) 



5.16+0.12(11) 



0.001 



MARW 



3.53-4.00 



4.13-4.36 



3.99-4.41 







3.82+0.12(12) 



4.23± 0.07 (15) 



4.15± 0.13(1 1) 



().()()() 



0.000 

 0.000 

 0.000 

 0.000 

 0.000 

 0.000 

 0.000 

 0.000 

 0.885 

 0.016 



0.000 

 0.000 

 0.001 

 0.019 

 0.000 

 0.008 

 0.001 

 0.000 

 0.002 

 0.000 



Fig. 2 Dorsal view of rostral part of skulls of a.) R. malayanus (BMNH 

 3.2.6.83 [holotype]), b.) R. s. stheno (BMNH 98.3.13.1 [holotype]) and 

 c.) /?. j\ microglobosus (HNHM 98.1.1. [paratype]). Scale = 5 mm. 



developed with distinct cusp, included in the toothrow. Lower middle 

 premolar (p3) small and fully extruded from the toothrow; first (p2) 

 and last (p4) lower premolars in contact or nearly so; p2 moderately 

 small and narrow, antero-posterior axis only slightly displaced rela- 

 tive to main axis of toothrow, unlike R. stheno stheno in which p2 is 

 slightly larger, overlaps more with the lower canine and p4. and in 

 which the axis is more skewed. 



Etymology. The Latin word microglobosus refers to the size and 

 shape of the median anterior rostral swellings which are considerably 

 smaller than those of the nominate subspecies. 



Comparisons with other taxa. Besides the classical morpho- 

 logical comparisons of the new subspecies, R. s. microglobosus and 

 the nominate subspecies. R. s. stheno, the Mann-Whitney U Test was 

 also performed to reveal if statistically significant differences were 

 present in morphological characters. In the course of the analysis 

 highly significant differences (highest p < 0.01) were shown in 

 greatest skull length, maxillary toothrow length, zygomatic width, 

 mastoid width, mandible length, lower tooth-row length, rostral 

 swelling width and median anterior rostral swelling width; in all 

 cases the new subspecies was smaller (Table 1 ). 



The same method was used for pair-wise comparisons between R. 

 malayanus and R. s. steno, and between R. malayanus and R. s. 

 microglobosus (see Table 1 for p-levels between groups). Significant 

 differences (at p < 0.01) were shown for the following variables: 

 forearm length, greatest skull length, lower toothrow length, mastoid 

 width, in which R. malayanus was smaller in each parameter, and 

 interorbital width where R. stheno was smaller. 



To help elucidate the relationships of the three taxa, a Principal 

 Component Analysis (PCA) was performed using the characters 

 recorded in Table 1. The scatterplots of the specimens against the 

 factor 1 (Fl)and factor 2 (F2) axes showed a c/ear separation of three 

 groups (Fig. 3) supporting the view that R. s. microglobosus repre- 

 sents a distinct taxonomic unit. The first two factors represent more 

 than 89% of the total variance where F2 was identified as the 'rostral 



