Is there any special name for this fingerpicking technique?
Yes. It is called the regular alternate thumb pattern.
It is indeed an African fingerpicking technique.
African fiddles in general are played with two fingers mainly (the thumb and the index finger), with occasional assistance from the middle finger in a pattern often referred to as the regular alternate thumb pattern. It is close to the classic arpeggio fingering style (for a pattern of two) which on the other hand is an utterance of the thumb and middle finger.
The regular alternate thumb pattern is a pattern which is often repetitive with a varieties of themes and variance just as fingering patterns (sequential order), syncopated rhythms, recitatives (based on regular language tonal expression used in communication involving local dialects), among other possible methods and pivoting mainly on the thumb finger usually for completing sequential loops of the harmony or simple utterances.
Please note that on a guitar this may extend to the use of the ring finger as the guitar is held in a manner that does not marginally require assistance from the hand of the player for stability.
Individuals mainly influenced with a taste, feel (whether played, watched or listened) or influence of typical native African instruments tend to limit themselves to a
i alternate movement pattern, with occasional
m, transposing this native African fiddle fingering technique, either knowingly or unknowingly, to the guitar.
Example of such instruments include the Kora and the Seperewa (Ghana mainly), both predominantly West African, which are mainly held and played directly with both hands, using thumbs and index fingers (with the middle finger occasionally) as other fingers contribute softly to grip and stabilise the instrument for fingering precision, even though supported sometimes and of late with a strap.