Orb-weaver Spider

Description:

I often have difficulty in identifying Orb-weavers, particularly when I am looking at one which could be a Neoscona sp. or an Araneus sp. These two genera tend to be so similar, that no amount of reading about them seems to help much and the search for an identification can soon become a matter of "pot luck" in which I rely on stumbling upon an exact match by looking at lots of pictures. There is not much science in that, but as an inexperienced amateur, sometimes that is the only way forward. There is one extremely useful identifier for Neoscona which immediately sets it apart from Araneus, but only when you can see it (it is often so faint, that it just cannot be seen, especially if your photos are are not so good, like mine). I am referring to the groove on the carapace. Wiki explains "Neoscona have a characteristic dorsal groove on the carapace that is parallel with the long axis of the body". So, until I can find a lucky picture, I have to go with Unidentified Araneidae.

Habitat:

Spotted in our front garden on a San Pedro Cactus (Echinopsis pachanoi). Plant identification from https://en.wikipedia.org/wiki/Echinopsis...

Notes:

Despite reading my way through these sites, I still have difficulty in differentiating Araneus spp. and Neoscona spp. However, they are packed full of good information. https://en.wikipedia.org/wiki/Araneus https://en.wikipedia.org/wiki/Neoscona