Excerpt from change request document:
It is our proposal that the entry currently listed as "Maykulan" (mnt) in Ethnologue 16 has a series of "alternate names" which actually represent a collection of languages under a Mayi group (currently Mayabic). These languages--Mayi-Kulan, Mayi-Thakurti, Mayi-Yapi, and Wunumara--will join the level of the existing Mayaguduna (xmy) and Ngawun (nxn).
There are multiple publications discussing the above-mentioned varieties as languages.
Pollock (2011) and Hinton & Hale (2004) clearly denote the Mayi-Yapi people as a separate people from their neighbors. Hinton & Hale illustrate this with a map of the region, a dotted line labeled "ethnographic boundary" dividing the Mayi-Yapi from the Mayi-Kutuna (2004: 21). Pollock lists various river catchments and local peoples, for example the Flinders River Catchment has listed under Indigenous peoples groups: Mayi-Yapi, Mayi- Kulan, Mayi-Thakurti, while other catchments have not all of these listed.
Blair (2001) cites several examples from the languages, for example "jerry-jerry, the annual herb Ammannia multiflora of Queensland, is from Mayi-Yapi and Mayi-Kulan, spoken around the Cloncurry Riverand the Norman River, north Queensland" (141-2).
Alpher (1991) in section 8.2 "Languages cited for etymological information" uses Mayi- Kulan and Mayi-Yapi languages as references.
ATSIDA has a database of language groups and peoples, listing the Mayi-Kulan, Mayi- Thakurti, Mayi-Yapi, and Wunumara peoples as separate entries. AusAnthrop also has separate entires for the peoples, under the names Maijabi, Mayi-Kulan, Mayi-Thakurti Wanamara.
I cannot neglect to mention perhaps the best publication concerning these languages, Breen's "The Mayi Languages of the Queensland Gulf Country" which provides, among other evidence, a 656 "concept list" with translations in all the Mayi languages illustrating the similarities and differences (e.g. 5). The book also provides an overview of cultural differences between the different peoples and notes several phonological differences between the languages (e.g. 29).