Sporades jaechi sp. nov. from Poum, New Caledonia is newly described and shown to be a member of the monophyletic Sporades subgenus Perileptosporades Deuve, 2010. Sporades millei Giachino and S. schuhi Donabauer are newly recognized as members of the subgenus Perileptosporades, and a key to its species is provided. Although Perileptosporades can be defined monophyletically relative to the rest of the genus, genitalic variation among species assigned to the nominate subgenus Sporades Fauvel, 1882 leave monophyly of that taxon ambiguously supported. Several morphological characters of long- standing use have been proposed to define the mutual monophyly of Sporades s. l. and its putative adelphotaxon, Trechodes Blackburn, 1901. Increasing knowledge concerning the diversity of male genitalic characters among Sporades spp. lends support to a recently proposed molecular phylogenetic hypothesis positing that Sporades evolved from within Trechodes. The consequences of the alternate phylogenetic hypotheses on their attendant nomenclature are discussed. An additional locality record for S. sexpunctatus Fauvel expands the known distribution of this species to include most of Grande Terre, New Caledonia.

aedeagus, genitalia, phylogenetics, taxonomy

Fauvel established Sporades for his species S. sexpunctatus (Fauvel 1882), placing the new genus in the tribe Trechini while noting that the elytra are basally grooved as in Pogonini, the apical palpomeres are narrowly cylindrical similar to those of Bembidiini, and the frontal grooves are very deep as in Trechus Clairville, 1806. Jeannel (1926) established a taxonomic framework for the World's trechine lineages, proposing Trechodini at the tribal level within a subfamily Trechinae, with Sporades placed next to Trechodes Blackburn, 1901. Trechodines were defined by Jeannel based on tridentate mandibles (mola, premolar tooth, and retinaculum present) with these projections obtuse; anterior tibia without an external apical spine; and male aedeagal median lobe with the dorsal surface membranous, the base not enclosed into a bulb.

Sporades remained monotypic until Uéno (1966) described two additional species. He noted the great similarity of the three species to Trechodes, suggesting that Sporades “is so close to Trechodes that it may be regarded as a subgenus of the latter (Uéno 1966: 29). ” Over the past 10 years, three more contributions have added eight names to the described fauna: Deuve (2010) described three new species; Donabauer (2011), two new species; and Giachino (2012), three new species. Deuve (2010) proposed Perileptosporades as a new subgenus, S. theryi Deuve as the type species, defining its monophyly by the labrum trilobed, i.e., the median excavation bearing a small tooth or broader protuberance at its deepest point; pronotum narrow and the median base straight, not extended posteriorly between the hind angles; and the pronotal lateral setae placed far forward near the pronotal front angles. The latter two authors were not aware of Deuve’s (2010) publication, and so did not attempt species placement relative to subgenus Perileptosporades.

This contribution adds one more new species to the New Caledonian Sporades fauna. The new species described below is placed in subgenus Perileptosporades, with a preliminary assessment of relationships of the five species assignable to that subgenus provided. Cladistic relationships of the two Sporades subgenera, and Sporades s. l. relative to Trechodes are discussed in light of information derived from morphological characters and molecular sequence data (Maddison et al. 2019), illustrating that complex interactions may result from linking taxonomic nomenclature to hypotheses of phylogenetic history. An additional locality for S. sexpunctatus Fauvel is reported, expanding the known geographical distribution of this species.

Sporades jaechi represents the fifth species of sg. Perileptosporades. Of the five species, S. theryi deviates most strongly based on larger body size, a different aedeagal median lobe configuration, a shorter, broader apex, and an extensive setal pelage on head, pronotum, and elytra (Deuve 2010). These deviations support S. theryi as the sister-group to the other four species. Sporades theryi is also one of the Perileptosporades involved in a sympatric species pair; it is sympatric with S. modestior at Pocquereux (Fig. 5). The other four species allopatrically divide Grande Terre, suggesting their speciation has been localized enough and recent enough to preclude development of secondary sympatry, or that sampling has been insufficient to discover sympatric populations. They are similar enough morphologically to suggest caution toward proposing a hypothesis of relationship. The various combinations of aedeagal median lobe configuration, the presence or absence and development of a dorsal setal pelage on head, pronotum or elytra, plus differential development of the recurrent stria may be informative, though no congruent hierarchy of character states strongly suggests a single phylogenetic hypothesis.

Jeannel (1926) compared Trechodes Blackburn and Sporades, and found them most similar among trechodine genera that he treated based on:

1. presence of the elytral basal groove;

2. the narrow, spindle-shaped apical maxillary palpomere contrasted to the broader, medially expanded penultimate segment;

3. a flat pronotum with mediobasal projection;

4. a deep sutural stria that is smoothly joined to the basal groove laterad the scutellum; and

5. a broadly widened aedeagal median lobe apex.

He noted that the two genera could be distinguished by the relatively short parameres of Trechodes spp. versus the robust, elongate parameres of Sporades sexpunctatus, the only species known at the time.

Also, the pronotum of Trechodes spp. is markedly protuberant medially along the pronotal base, with the pronotal hind angles situated well forward of the median base. Trechodes attains a very broad geographic distribution, ranging from Australia, the Philippines, Southeast Asia, Madagascar, and Africa (Jeannel 1926), with distributions of subsequently described species falling within that realm: T. sicardi, Madagascar (Alluaud 1932); T. lepesmei, Cameroon (Villiers 1940); T. vadoni, Madagascar (Jeannel 1946); T. leleupi, Congo (Basilewsky 1950); T. katanganus, Congo (Basilewsky 1958); T. jeanneli, Madagascar (Mateu 1958); T. crypticus and T. lustrans, Australia (Moore 1972); T. daffneri, Zaire (Casale 1986); T. leclerci, Thailand (Deuve 1987); T. palawanensis, the Philippines (Deuve 2001); T. satoi, Thailand (Uéno 1990); T. laophilus, Laos (Deuve 2002); and T. lucanerii, Ethiopia (Magrini et al. 2005). Maddison et al. (2019) reported an undescribed species from India. The morphological interpretation of Trechodes has remained remarkably constant across this series of authors describing species from tropical areas spanning 140° latitude. In all species, the male protarsomeres have the basal two segments denticulately expanded lateroapically (e.g., Jeannel 1926, Deuve 2001), a plesiomorphic condition shared with all Trechodina except Sporades, which have only the basal protarsomere expanded and bearing squamose setae ventrally.

The aedeagus of Trechodes spp. is characterized by an elongated median lobe with a narrowly attenuated apex, the tip of that apex bearing a hook, knob, or another type of curved appliance. For many of the species, the presence of spines on the internal sac is documented (e.g., Moore 1972, Casale 1986, Deuve 1987, 2001, Uéno 1988, 1990). All species exhibit a profound mediobasal pronotal protuberance, and polished glossy cuticle often with light and dark contrasting transverse elytral bands (e.g., Casale 1986; fig. 2; Deuve 1987: fig. 3; Uéno 1990 fig. 1).

Monophyly of Sporades relative to Trechodes is established based on the derived condition of only the basal male protarsomere dilated and bearing ventral squamose setae, and the presence of a fine setal pelage on the elytra (Uéno 1966), that pelage also variously present on the head or pronotum among the species (Deuve 2010, Donabauer 2011, Giachino 2012). Conversely, the uniform configuration of the pronotum in Trechodes spp. with its medially protuberant base has been used to support its monophyly relative to Sporades. Among the 12 Sporades spp., the derived, broadly rounded aedeagal median lobe apex observed in males of M. jaechi (Fig. 4) is shared with other members of sg. Perileptosporades: S. millei, S. modestior, S. schuhi, and S. theryi. This character in conjunction with the medial tooth in the labral excavation, and placement of the lateral seta far forward on the pronotum establishes Perileptosporades' monophyly. The remaining seven species consigned to the nominate subgenus Sporades exhibit a more heterogeneous range of genitalic characters. The generotypic S. sexpunctatus exhibits a uniquely inflated and twisted male median lobe apex (Jeannel 1926), whereas S. macrops (Uéno 1966) and S. daccordii (Giachino 2012) exhibit an elongate median lobe with an apical knob just apicad the ostial opening. In contrast, S. testaceus exhibits a very narrow, short, and apically rounded median lobe that barely extends beyond the parameral setae (Uéno 1966). Sporades perileptoides (Donabauer 2011) and S. beatricis (Giachino 2012) have a broader, foreshortened median lobe with a very narrow, rounded apex. And finally, the median lobe of S. tachysoides (Deuve 2010) is extremely foreshortened and broadly rounded apically. That so much variation occurs within the New Caledonian radiation of these species, whereas the aedeagus of Trechodes spp. consistently exhibits an apically attenuated and apically modified configuration across much of the Palaeotropical region begs explanation.

Recent molecular systematic results (Maddison et al. 2019) that include six Trechodes spp. plus S. sexpunctatus among 259 species representing 99 described genera of Trechitae find the two genera most closely related. Indeed, given the published taxonomic sampling scheme the single Sporades representative is the sister taxon to the Australian species pair, T. bipartitus (MacLeay) and T. secalioides (Blackburn); although bootstrap support for these relationships is not strong and more complete taxonomic sampling is called for. These three species, in turn, are the sister group to the species pair, T. marshalli Jeannel of Africa and T. jeanneli Mateu of Madagascar. The last two Trechodes spp. in the analysis, T. alluaudi Jeannel of Madagascar and T. sp. “India: Karnataka”, are successive sister groups to the previously mentioned species. The phylogenetic relationships of these taxa embrace the Indian Ocean, consistent with Jeannel's hypothesis that Trechodes was vicariated via the fragmentation of Gondwana: “Les Trechodes sont les restes de la vieille faune tropicale des débris du continent de Gondwana ... (Jeannel 1926: 487)”. However, the molecular systematic hypothesis whereby Sporades is derived from within the eastern, Australian Trechodes fauna, consistent with the suggestion that Sporades “may be regarded as a subgenus (Uéno 1966, p. 29)” of Trechodes, suggests that the putatively derived morphological characters supporting monophyly of Trechodes relative to Sporades, e.g., protruding mediobasal lobe of the pronotum, elongate male aedeagal median lobe with attenuated apex, relatively short male parameres, are either incorrectly polarized, or may transform to states present within Sporades. Certainly the male aedeagal median lobe characters might be so transformed, as the elongate lobe with an apical knob observed in S. macrops and S. daccordii is exceedingly similar to the aedeagus of Trechodes marshalli (Basilewsky 1958, fig. 13a). Thus, with regard to aedeagal characters, T. marshalli may serve as the phylogenetic nexus between Trechodes and Sporades. Short parameres relative to overall median lobe length have also been proposed to diagnose Trechodes (Jeannel 1926: 486), however the parameres of T. daffneri (Casale 1986: fig. 3B) are more elongate and not dissimilar in relative length to those of Sporades spp. The extensive aedeagal evolution within Sporades could thus be derived via modification of these various Trechodes configurations. Also, the mediobasal pronotal protuberance of Trechodes is an extreme version of the moderately lobate condition observed in S. tachysoides and S. perileptoides. Species of sg. Perileptosporades exhibit an even shorter mediobasal marginal expansion (e.g., Fig. 1); this too could represent a further derivation relative to the pronotal configurations of Trechodes and Sporades s. s. By this interpretation, the lobate Trechodes pronotum is plesiomorphic in this area of the cladogram, and reduction of the basal lobe is a derivation restricted to Sporades.

This contribution maintains the taxonomic independence of Trechodes and Sporades in the face of ambiguously conflicting morphological and molecular phylogenetic evidence. Both genera are presently diagnosable via observable morphological characters, although the polarity of their attendant character states may require reassessment in light of additional phylogenetic data from all sources. Should these two genera be synonymized in order to recognize monophyletic taxa, the geographically widespread Trechodes Blackburn, 1901 must fall into synonymy under the New Caledonian precinctive Sporades Fauvel, 1882. Such a happenstance illustrates that taxonomic nomenclature operates by stable rules (I.C.Z.N. 1999), whereas phylogenetic analysis must respond to the preponderance of data. This contribution continues the dogged pursuit of trechodine diversity that stretches back to Fauvel (1882), Blackburn (1901), and Jeannel (1926); that pursuit a recurring first step toward hypothesizing patterns of evolution for the group.

I thank Manfred Jäch, Museum of Natural History, Vienna, for the loan of New Caledonian specimens, and Arnaud Faille for his thorough and insightful review of the manuscript. To a person, all describers of Sporades have strived to provide information not only sufficient to diagnose the species, but also to advance scientific understanding of this taxon. These efforts are acknowledged, as they establish the basis for description of this new species without risk to the type specimens of these rarely collected species.