Abrolophus Berlese 1891
Creators: name: Seeman, Owen D.
name: Beard, Jennifer J.
name: Fan, Qing-Hai
name: Otto, Jürgen C.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Trombidiformes
Erythraeidae
Abrolophus

description: Abrolophus Berlese, 1891
Type species: Trombidium quisquiliarum Hermann, 1804
Diagnosis (from Wohltmann & Mąkol 2012): Adults and deutonymphs. Palp tarsus relatively small (not enlarged and spherical), not or only slightly extending beyond odontus. Crista metopica composed of two sensillary areas connected by well-developed rod. Posterior process of crista (if present) weakly marked. Crista situated on distinct scutum, which may be weakly developed in the lateral and posterior parts. One pair of eyes, each eye located laterally on prodorsum, at the level of posterior part of crista. Dorsal opisthosomal setae simple, either nude or setulose, or with husk-like setules. Coxae I and II fused, coxae III and IV fused, the latter with an accessory sclerotised rim. Larvae. Palp femur with two setae. Palp genu with two or three setae. Odontus simple or bifurcate at termination. One tibial seta modified into paradont, placed dorsally behind the odontus. Scutum triangular, pentagonal or hexagonal in outline, wider in the anterior part, then narrowing posteriorly, with two pairs of trichobothria and two pairs of normal setae. Anterior trichobothria (ASens) located between setae AL and PL, or slightly shifted behind the PL bases. Posterior trichobothria (Psens) placed close to the posterior margin of scutum. One eye present on each side of prodorsum, at the level of posterior part of scutum. Idiosoma venter with more than 10 setae between coxae II and III. Coxae I–III with one seta each. Legs relatively short. Trochanter I–III with two setae each; microseta κ on tibia I prominent, about double the size of microseta κ on genua I, II. Tarsi I–III terminated with paired claws and claw-like empodium. Terminal eupathidia on tarsi usually covered with barbs.
Remarks. Abrolophus is the sole genus of Abrolophinae, thus the above diagnosis—based on characters visible from light microscopy—serves as a companion to the subfamily definition of Witte (1995). The above diagnosis largely fits for Abrolophus novaeguinensis, A. ripicola and A. zelandicus, except that they are among the species with a weakly developed scutum.
The putative larva of A. ripicola, Mypongia brevipes, does not fit this diagnosis as it has no palp tibial seta modified as a paradont, has no distinct scutum (thus AL and PL are in plicate cuticle), coxa I has two setae, coxa II lacks setae, and genu I lacks microseta κ. Therefore, if M. brevipes is the larva of A. ripicola, as we suspect, then the higher classification of larval and post-larval stages is discordant. Definitive evidence linking these species would put the question beyond doubt, but bigger questions of higher classification remain, and will benefit from molecular techniques, such as combined analysis of mitochondrial genomes, Sanger sequencing and ultra-conserved elements.
description: Published as part of Seeman, Owen D., Beard, Jennifer J., Fan, Qing-Hai & Otto, Jürgen C., 2024, Abrolophus from Australasia, and the mysterious Mypongia (Trombidiformes: Parasitengona: Erythraeidae), pp. 151-189 in Zootaxa 5519 (2) on page 187, DOI: 10.11646/zootaxa.5519.2.1, http://zenodo.org/record/13915687