Penile spine

Definition
noun, plural: penile spines
Any of the spiny projections along the glans or the shaft of the penis
Supplement
The penile spines are spines along the glans and/or the shaft of the penis in certain animals. They are made up of overlapping layers of keratinized material and are of different morphologies. They may be classified into three categories based on their shape and size. In type 1, the penile spines are simple, small, and single-pointed structures with moderate length. An example of type 1 is that of the common marmosets. Type 2 penile spines are robust simple spines that are single-pointed as well but have larger and often thick bases. An example is that of Galagoides demidoff (Prince Demidoff’s bushbaby). Type 3 penile spines are complex spines. They are multi-pointed (i.e. two or more per spine) and larger in size. An example is that of Otoleur garnettii (greater galago).¹ Penile spines are found in many mammals (e.g. felines, jaguars, pumas, chimpanzees, mice, wombats, echidnas, bats, primates, rodents, etc.) and certain bird species. Humans lack penile spines however a morphological variant called hirsuties coronae glandis or peraly penile papules occur in certain human penises. Small protuberances (~1 mm to 3mm) around the corona or sulcus of glans penis occur in certain males. These papules are said to be vestigial remnants of penile spines.
See also:

• glans penis
• hirsuties coronae glandis

Reference(s):

¹ Dixson, A. (2012). Primate sexuality : comparative studies of the prosimians, monkeys, apes and human beings. Oxford: Oxford University Press. p.