Original paper
Diverse Liberiblattinidae (Insecta: Blattaria) from Lebanese and North Myanmar amber document allometric modifications near lowest size limit
Sendi, Hemen
Palaeontographica Abteilung A Band 321 Lieferung 1-6 (2022), p. 127 - 148
109 references
published: Jan 10, 2022
published online: Nov 3, 2021
manuscript accepted: Mar 12, 2021
manuscript received: Jan 16, 2021
Abstract
Mesozoic cockroaches of the cosmopolitan family Liberiblattinidae, Miniblattina libera gen. et sp. n. from Barremian Lebanese amber, and Stavba magnoculara, and S. delicata spp. n. from Cenomanian North Myanmar amber are reported. The former differs from other genera of the family in the extremely small size, sharply triangular subgenital plate and tubular ovipositor. S. magnoculara is autapomorphic in having extremely elongated antennae (with ca. 140 segments), pronotum more elongated, less circular, elongated wings, and distinctly larger size (12.06 mm), while S. delicata has a unique long antennae (with ca. at least 70 segments), and a triangular pronotum. A morphologically based phylogenetic reconstruction reveal that Nocticolidae and Latindiinae form a clade (97 % support in the consensus and bootstrap analyses, 98.4 % in the Bayesian network tree), with Stavba Vršanská et Vršanský, 2019 in Vršanský et al. (2019)) (Liberiblattinidae) being paraphyletic with respect to them. Their sister clade includes all species of Stavba, except basal S. delicata and S. magnoculara, revealing 90 % support in both consensus and bootstrap analysis, and 79 % in the Bayesian network tree). Crenocticola Li et Huang, 2019 was insignificantly posed as sister taxon with respect to the Stavba clade in the Bayesian network tree, while in other analyses Crenocticola is housed in a polytomy within Nocticolidae. M. libera is one of the most miniaturised fossil cockroaches with a body length of about 3–3.5 mm. Considerable structural changes related to miniaturisation include allometric reductions and simplifications in Bauplan (reduced venation, supported costa, wings with thick veins, oligomerised cerci). The ovipositor is long compared to the rest of the body. Very small morphotypes also occur in many extant cavernicolous Nocticolidae, myrmecophilous Attaphila Wheeler, 1900 and extinct beetle-like Umenocoleoidea (also in Anaplectinae Walker, 1868, Prosoplecta Saussure, 1864, and Permoponopterix Nel et al., 2014), indicating that miniaturisation occurred independently in these lineages. Miniaturisation and/or associated change of diet (towards fungivory and algaeovory) or predation pressure might have represented an ancestral preadaptation of Nocticolidae resulting in the invasion of caves.
Keywords
Fossil insect • cockroach • Blattodea • Mesozoic • new species