Nesamblyopina Sokolov 2023, subtribe nova
Creators: name: Sokolov, Igor M.
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Carabidae

description: Nesamblyopina, subtribe nova
Type genus: Nesamblyops Jeannel, 1937 (here designated).
* Med—medial setae, MedProx—medial proximal seta, Bas—basal seta;
** Ø mscx—diameter of mesocoxa;
*** 5 & 6USP—5th and 6th pores of umbilical series; “5=6” means: the distance from 5th pore to elytral margin equals the distance from 6th pore to elytral margin
Subtribal name. Based on the name of the type genus.
Recognition. The new subtribe comprises members of Anillini with the following combination of diagnostic features: (1) basistipes of maxilla with four setae (two basal and two medial), of which outer basal and both medial stipital setae of similar length (Figs 2A–B, bss, mss); (2) posterior angles of pronotum rounded and without basolateral denticles (Figs 3A–B); (3) basal margin of pronotum lacking marginal setation (Figs 3A–B, cf. with Figs 3F–I, bst); (4) pterothorax with well-developed mesothoracic anapleural sutures (Figs 4A–B, msts); (5) metaventrite (Figs 4A–B, mtv) very short with distance between meso- and metacoxae about 0.15–0.20 diameter of mesocoxa; (6) metaventral process (Figs 4A–B, mtp) narrowly margined; (7) metendosternite of T-shape, without visible lateral arms (Figs 5A–D); (8) elytra with umbilical series of eight pores situated along virtual line almost parallel to lateral elytral margin (Figs 6A–B); (9) protibia with short oblique notch and short posterior setal row of 4–6 setae (Figs 7A–B, psr); (10) basal lobes of median lobe of males asymmetrical (Figs 14–16); (11) ovipositor of females with gonocoxite 2 with three (1 medial + 2 lateral) ensiform setae (Figs 8A–B, mes, les1–2).
Relationships within Anillini. The new subtribe represents a morphologically distinct lineage within the tribe Anillini and differs from other tribe representatives in many important characteristics of the labiomaxillary complex, pronotum, pterothorax, elytral and leg chaetotaxy as well as the structural details of the male and female genitalia, traits which did not attract significant attention from researchers who worked on the taxonomy of Anillini.
Labiomaxillary complex. The members of Nesamblyopina have setae of undifferentiated length on the basistipes (plesiomorphic state).This distinguishes them from other representatives of Anillini, which have the medial proximal seta on basistipes much longer than the others (derived state) either in the basal position (members of Typhlocharina, cf. Fig. 3, p. 12 in Serrano & Aguiar (2006); Fig. 2d, p. 39 in Andujar et al. (2008); Fig. 2b, p. 51 in Andujar et al. (2010)) or closer to the middle of sclerite (members of Anillina and Scotodipnina, as in Figs 2C–F, mss).
Pronotum. The vast majority of anilline taxa have a pronotum with basolateral denticles and posterior angles with varying degrees of prominence (cf. anilline fauna of Greece in Giachino & Vailati 2011). Rounded posterior angles are rare among anillines and have been reported for several genera only. Within its distributional range, the members of Nesamblyopina share the state of rounded posterior pronotal angles with their geographical and ecological neighbours, the anilline species of the genus Zeanillus Jeannel (cf. Figs 3A–B and 3G). Outside New Zealand, the members of Nesamblyopina share the state of rounded posterior angles with the following genera of the Old World: cavernicolous European Aphaenotyphlus Español & Comas (Ortuno & Sendra 2007) and a group of African and Madagascan genera with shortened elytra, such as Bulirschia Giachino, Caeconannus Jeannel, Cryptorites Jeannel, and Microdipnites Jeannel (Giachino 2008, 2015). Interestingly, none of the species of Anillini with rounded posterior angles of the pronotum have been documented in the New World to date. It seems that all cases of similarity in the shape of the posterior angles between Nesamblyopina and Old World anillines are homoplastic, since this state of character arose in different phyletic lineages and subtribes of the tribe.
Another pronotal character, the setation of the basal margin of the pronotum, is also widely distributed among the representatives of Anillini. Like the situation with the state of posterior pronotal angles, cases where setation is lacking are not common among the species of the tribe. Noteworthy, the members of Nesamblyopina share the lack of setation on the basal margin of the pronotum with the North American lineage of Anillini, specifically, Anillinus Casey, Serranillus Barr, Anillodes Jeannel, Anillaspis Jeannel, and Medusapyga LaBonte & Maddison (2023). Recent results of molecular analysis have placed all these North American genera in a separate clade on the phylogenetic tree of Anillini right above the Nesamblyops clade, i.e., as a sister clade to all other Anillini except Nesamblyops (Andujar et al. 2016; Maddison et al. 2019). To date, the lack of setation of the basal margin of the pronotum is the only known morphological trait allowing researchers to distinguish the members of the North American Anillini from other members of the tribe. In accordance with the basal positions of both clades on the tree, such state of setation can be treated as a symplesiomorphy for both clades. Unfortunately, the taxon coverage in the abovementioned molecular analyses of Anillini is far from perfect, given that only 17 genera were analyzed from almost 100 described to date. Therefore, clade positions on the tree and their composition might be subject to change in the future after additional material is examined in molecular analysis.
Pterothorax. The structure of the pterothorax of the members of Nesamblyopina differs significantly from that of other Anillini in many aspects. For instance, mesothoracic anapleural sutures can be observed in all representatives of the tribe on microscopic slides in translucent light. However, external traces of sutures are obliterated (apomorphic state) and cannot be seen on specimens in direct light in all anillines in which the mesothorax configuration is documented (cf. Figs 4C–I with Figs 4A–B, msts). At present, the members of Nesamblyopina are the only anillines that have externally visible mesothoracic anapleural sutures (plesiomorphic state).
An entirely similar situation exists with the metaventral process. All anilline species in which the metaventrite configuration is documented possess an unmargined metaventral process, whereas the members of Nesamblyopina have a metaventral process with a distinct and narrow margination (cf. Figs 4A–B with Figs 4C–I, mtp). Unfortunately, polarity for this character cannot be determined with certainty.
The members of the tribe Anillini are flightless species, and it is clear that different parts of their pterothorax may have undergone different degrees of reduction over the course of their evolution. For Anillini, this is true in terms of the length of the metaventrite and the shape of the metendosternite. In our case, the members of Nesamblyopina possess the shortest metaventrite among the species of Anillini (cf. Figs 4A–B with Figs 4C–I, mtv) in which the configuration of metaventrite is documented. Given that many taxa among Anillini exhibit reduced elytra, which sometimes can reach only half the length of the abdomen, it is reasonable to expect that species with very short metaventrite may be discovered in the future among other anillines also. Additionally, the members of Nesamblyopina possess reduced configuration of metendoventrite without distinct lateral arms. They share the lack of lateral arms with the species of several genera whose structures of metendosternites are documented, like Anillinus, Serranillus, and Geocharidius Jeannel (cf. Figs 5A–D with Figs 5E–H, mtes, and both with the species that have lateral arms as in Figs 5I–P, mtes). Together with the fact that Anillinus and Geocharidius belong to different clades on the phylogenetic tree of Trechinae (Maddison et al. 2019), in both cases states of metaventrite and metendosternite in Nesamblyopina may be considered as homoplastic.
Elytral chaetotaxy. The members of Nesamblyopina have eight pores in the elytral umbilical series, while the vast majority of the species of Anillini have elytral umbilical series with nine pores (all species of subtribes Anillina and Scotodipnina with fully developed elytra). Nevertheless, the eight-pore configuration in the umbilical series can be found in some members of the subtribe Typhlocharina (e.g., cf. Figs 6A–B, with the umbilical series of Typhlocharis [now Lusotyphlus] algarvensis Coiffait on Fig. 1, p. 151, or with the umbilical series of Typhlocharis silvanoides Dieck on Fig. 2, p. 141 in Zaballos & Perez-Gonzales (2010, 2011) respectively). It is supposed that this configuration of the umbilical series of pores in Typhlocharina arose as a result of the adaptations to the endogean way of life (Jeanne 1973). However, the majority of species of Nesamblyopina are litter-dwellers, so similar elytral chaetotaxy in these two subtribes presumably evolved independently, and it is likely, in this case, that the resemblance is homoplastic.
Structure of protibia. The members of Nesamblyopina exhibit an obliquely sloped apicolateral edge of the protibia. On the posterior surface of the protibia, there is a row of 4–6 setae (Figs 7A–B, psr) that are positioned adjacent to the edge and do not protrude beyond the slope edge (plesiomorphic state). This row is equivalent to the “distal cluster” of Hlavac (p. 52, Fig. 3, DC, abbreviations on p. 65 (1971) and the erroneously cited “distal comb” in Maddison et al. (2019). All other anillines with a documented protibial structure have an apicolateral edge of the protibia with a notch that varies in the degree of concavity. This notch is associated with a row of 9–15 setae on the posterior surface, which protrudes beyond the edge of concavity, thus forming a kind of “comb” on the protibial apex (derived state) (cf. Figs 7C–H with Figs 7A–B, psr).
Male genitalia. The symmetry/equality of the basal lobes of the median lobe of males is considered to be a synapomorphy of Anillini. However, within the tribe, many taxa actually demonstrate unequal basal lobes. This character state may characterize either whole genera or a particular species (e.g., cf. images of male median lobe of Serranillus in Sokolov & Carlton (2012), of Geocharidius in Sokolov & Kavanaugh (2014), of Zapotecanillus Sokolov in Sokolov (2013), of Anillinus aleyae Sokolov & Watrous in Sokolov & Watrous (2008), and of A. robisoni Sokolov & Carlton in Sokolov et al. (2004)) and likely evolved independently in different taxa of Anillini, including Nesamblyopina.
Setation of ovipositor. The members of Nesamblyopina have ovipositor with three ensiform setae, represented by one medial and two lateral setae (Figs 4A–B, les1–2, mes). This state of ovipositor is not known in other species of Anillini. The representatives of the subtribes Anillina and Scotodipnina, in which female genitalia are documented, have only two ensiform setae on the ovipositor, of which one is in a lateral position and the other is in a medial position (cf. Figs 8C–F, les1, mes, with Figs 4A–B, les1–2, mes). Members of the subtribe Typhlocharina demonstrate variations in the number of ensiform setae from 0 to 1. These cases of variation occur in parallel to the changes in shape of gonocoxite 2, which varies in the representatives of Typhlocharina from the typical unguiform to a unique tubular shape (Perez-Gonzales & Zaballos 2012; Perez-Gonzales et al. 2018).
Relationships outside Anillini. As described above, a certain number of characters indicative for the subtribe have not yet been documented for the species of the tribe Anillini. To determine how widely such characters are distributed among the representatives of Trechinae, especially within taxa from the sister clades to the Anillini clade on the phylogenetic tree of Trechinae (Maddison et al. 2019), members of the genera of Sinozolini, Zolini, Bembidiini and of both subtribes of Tachyini (i.e., Tachyina and Xystosomina) were examined. Results of this investigation are presented in Table 1. The results show that character states indicative for the new subtribe are widely distributed among the examined non-anilline genera and can thus be interpreted as plesiomorphic. Especially amazing is the concordance in character states between Nesamblyopina and the species of the genus Xystosomus Schaum (Xystosomina, Tachyini). The members of Nesamblyopina share the states of seven from nine characters shown in Table 1 with the species of the genus Xystosomus, while the other representatives of Anillini shown in Table 1 share at most the state of only one character with the members of Nesamblyopina. Nevertheless, because of the paucity of detailed morphological descriptions for many genera of Anillini in particular and Trechinae in general, additional morphological investigations are necessary to elucidate the relationships between Nesamblyopina and other basal taxa of Trechinae.
By considering all comparative morphological data, it seems reasonable to state that the new subtribe is characterized by a combination of mostly plesiomorphic traits, pointing out that Nesamblyopina constitutes presumably an ancient relic lineage within Anillini. This assumption is in concordance with the basal position of the Nesamblyops clade on the phylogenetic tree of Anillini obtained in molecular analyses (Andujar et al. 2016; Maddison et al. 2019).
At this time, the new subtribe includes one genus.
description: Published as part of Sokolov, Igor M., 2023, Fourteen new species of the genus Nesamblyops Jeannel (Coleoptera: Carabidae: Anillini) from the South Island of New Zealand with redescription of the genus and description of a new subtribe, pp. 151-192 in Zootaxa 5375 (2) on pages 153-164, DOI: 10.11646/zootaxa.5375.2.1, http://zenodo.org/record/10184224