Philippinozercon Gerdeman, Garcia, Herczak & Klompen, 2018

Gerdeman, Beverly S., Garcia, Rufino C., Herczak, Andrew & Klompen, Hans, 2018, Philippinozercon, a new genus of Heterozerconidae (Parasitiformes: Mesostigmata), with description of all active instars, Zootaxa 4540 (1), pp. 7-22 : 10

Philippinozercon Gerdeman, Garcia, Herczak & Klompen gen. nov.

Type species: Philippinozercon makilingensis Gerdeman, Garcia, Herczak & Klompen sp. nov.

Diagnosis (based on adults). With the following combination of characters: adults with only three setae on the palp genu (unique); lacking series of spine-like setae latero-ventrally on the idiosoma; metapodal shields with acute postero-lateral angles (unique); setae Jv5 inserted posterior to the fusion line of the ventral and anal shields; with one pair of greatly elongated setae inserted on the postero-marginal shield. Female with a strip-like sclerite between the geniti-ventral and the endopodal-sternal shield remnants; sternal setae st3 inserted on soft cuticle. Male with sternal setae st3 on endopodal-sternal shield remnants (unique); seta pl1 on femora II hook-like and spinose.

Comparisons with related taxa (adults). Based on literature data and the collections of Heterozerconidae at the OSAL, there are at least two genera of Heterozerconidae in S.E. Asia. Allozercon is found throughout the region, while Philippinozercon so far has only been found in the Philippines. The two genera can, and occasionally do, co-occur on a single host individual. They are probably closely related, sharing a number of characters relative to Heterozerconidae from Africa or the New World:

1. setae st 3 in the female on shieldlets that are not fused to the geniti-ventral shield (vs. inserted on the geniti-ventral shield).

2. setae st 1 in the male on a contiguous endopodal shield (vs. on separate shieldlets with lyrifissure iv1 only ( Amheterozercon , Narceoheterozercon , Heterozercon ).

3. setae st 2 in the male on distinct endopodal shield (shared with Amheterozercon ), vs. free ( Heterozercon ) or on the sterniti-ventral shield ( Narceoheterozercon ).

Note: Characters 2–3 cannot be coded for Maracazercon and Afroheterozercon which have fused endopodal and sterniti-ventral shields.

4. lateral opisthosomal setae not modified (vs. distinctly modified in Amheterozercon , Maracazercon , Heterozercon , Afroheterozercon ).

5. setae Jv5 inserted posterior to fusion line of the ventral and anal shields (vs. anterior to that line).

6. seta pv1 on genua and tibiae II of male spinose (vs. setiform). Males of Heterozercon have a spinose ventral seta on genu and tibiae II, but this appears to be av1, not pv1.

7. both genera may share tocospermous, rather than podospermous, mating systems ( Di Palma et al., 2015), despite the presence of a spermatodactyl in the males. This characteristic is tentative, it has only been examined in detail in one Asian and two American species. It clearly needs to be studied in more taxa.

Philippinozercon can be differentiated from Allozercon species by:

1. the presence of a strip-like sclerite between the geniti-ventral and the endopodal-sternal shield remnants in the females (absent in Allozercon ).

2. the acute postero-lateral angle of the metapodal shields (rounded in Allozercon ), unique.

3. the reduction in setal complement of the palp genu in the adults from 6 to 3, unique.

4. the shape of seta pl1 on femora II of the male: hook-like and spinose (vs. a straight spine or setiform).