Male. Body dorsally flat, slender, ~4–10× long as wide, without chromatophores; somites all subsimilar in width, somites sub-rectangular or trapezoidal, lateral margins of head and pereionites sub-parallel. Pleon of one segment, with free lateral margins. Head with weak or absent rostrum, without pseudorostrum. Eyes absent. Antennula with maximally 4 flagellar articles. Antenna flagellum longer than podomeres. Antennal scale (rudimentary exopod) present, even if more or less developed among genera. Mandible incisor with 2 to 8 cusps; molar process subconical, without grinding surface, with apical unequal smooth and pinnate setae; spine row and lacinia mobilispresent, the latter only on left mandible. Maxilliped slender, covering entire mouthpart field, endite distal margin narrowly rounded; epipod slender, quadrate or distally acute; palp composed of 5 articles; 2 stiff pectinate setae always present on maxilliped distal article. Pereiopods 1–7 subsimilar, always without subchela; all pereiopods with 2 dactylar claws; pereiopods articulating dorso-laterally or laterally, and projecting ventrally (in Janinella and Microcharon) or outwards (in Lepidocharon). Penial processes with openings coalescent and medial. Male pleopods 1 and 2 not operculate; male pleopod 1 distally rounded or subtruncate, with or without acute distolateral lobes; proximal part of the pleopod with or without scale-like elements on postero-lateral margins; stylet-guiding grooves running parallel to the lateral free distal margin of pleopod 1 and folded by a hyaline lamella (transversal and unfolded in Janinella); pleopod 3 endopod with 3 plumose setae (marine taxa) or without plumose setae (freshwater taxa), exopod slender. Pleopod 4 globular, pleopod 5 absent. Uropods biramous, ventrally inserted on pleotelson, protopod large, c. 0.5–1.3 as long as pleotelson; protopod length/width ratio c. 2.5–4.5; rami slender with exopod articulating anteriorly to endopod. Anus terminal, not covered by pleopods. Anus outside pleopodal chamber, between bases of uropodal protopods.

Female. Operculum (pleopod 2) from sub-quadrate (as long as wide) to more than 2 times longer than wide, with free distal margin deeply incised medially, faintly incised, or without medial incision, armed with 4 or 2 setae, or unarmed.

Microcharon Karaman, 1934; Janinella Albuquerque, Boulanouar & Coineau, 2014; Lepidocharon Galassi & Bruce, gen. n.

Angeliera Chappuis & Delamare Deboutteville, 1952.

Wilson and Wägele (1994) and Wilson (1994) critically discussed the status of the Microparasellidae in relation to the Janiridae on a cladistic phylogenetic basis. Wilson and Wägele (1994) in their review of the Janiridae analysed the status of the family Microparasellidae in detail, reviewing the history of the debate over the status of the family. Wilson (1994) also included the Microparasellidae in his cladistic analysis of the phylogeny of the Janiridae. Wilson and Wägele (1994: page 721) stated “The family concept of the Microparasellidae may be open to challenge becauseMicroparasellusis distinct from the other three genera in these autapomorphies”, these being the differences in the somatic and uropodal morphology. These authors went on to say “the composition of this family will require further study.” In Wilson’s (1994) analysis, there were no supporting apomorphies for the Microparasellidae as then constituted, but there were separate supporting apomorphies for the genus Microparasellus and the clade holding the remaining genera, strongly suggesting that potentially these were two monophyletic clades, albeit the Microparasellidae being monogeneric. The principle basis for this is that each group had unique and derived uropod morphology and substantial differences in body morphology.

The description of the new genus Lepidocharon Galassi & Bruce, gen. n. led to a re-appraisal of the taxonomic status of the Microparasellidae and its constituent genera. We conclude that the Microparasellidae is a mono-generic family supported by a prominent acute or narrowly rounded rostrum, the antennal flagellum shorter than podomeres, all somites with straight lateral margins that also have scales, an indisputable ventral position of the pereiopods, the unique uniramous and short uropods (see Appendix 1). The remaining genera are housed in the new family Lepidocharontidae fam. n., the diagnostic characters being the elongate body (up to 10× as long as maximum width), a weak or absent rostrum, the antennal flagellum longer than podomeres, the pereionites rectangular or trapezoidal in dorsal view, with sub-parallel lateral margins, a lateral or dorso-lateral position of the pereiopods, a tendency to reduction of pereiopodal coxal plates, and the uropod with a large protopod with the exopod articulating anteriorly and separately to the endopod.

Within the family Lepidocharontidae there is great uniformity of the diagnostic characters among all the genera. The genus Angeliera has been placed incertae sedis in the Asellota on the basis of marked differences in several morphological features that set this genus far away the basic body plan observed in Lepidocharontidae.

The largest genus in the Lepidocharontidae is Microcharon with 77 species, both marine and freshwater. Many species lack full descriptions, and there are inconsistencies in the distribution of certain characters within the genus. A dorsal view of the head is not routinely figured; when figured, it can be seen that some species do have a rostral point or rostrum, while others have the anterior margin of the head weakly concave.

The generic name Microcharon is unavailable under the ICZN (1999)’s rules because the genus was established by Karaman (1934) without type species designation. This prevents the use of “Microcharontidae” (from the most speciose and well-known genus Microcharon) as the family name because ICZN (1999)’ article 13.2 unambiguously states: “To be available, every new family-group name published after 1930 must satisfy the provisions of Article 13.1 and must be formed from an available genus-group name then used as valid by the author in the family-group taxon [Arts. 11.7.1.1, 29]”. Therefore we here propose the name Lepidocharontidae fam. n.

The family name Microparasellidae was first introduced by Karaman (1934: page 44) when describing the genus Microcharon, although the family had been earlier diagnosed by Karaman (1933: page 17) with the accompanying statement “Microparasellusn. fam., n. gen.”, but without type-species designation for the genus Microparasellus (see Karaman 1933). According to the ICZN (1999: Article 13.2) the family name Microparasellidae proposed by Karaman (1934) is thus a nomen nudum, because the family was erected on the unavailable generic name Microparasellus Karaman, 1933 that lacked type-species designation. Nevertheless, Article 13.2.1 states that “A family group name first published after 1930 and before 1961 which does not satisfy the provisions of Article 13.1 is available from its original publication only if it was used as valid before 2000, and also was not rejected by an author who, after 1960 and before 2000, expressly applied Article 13 of the then current editions of the Code”. The family name was considered valid until 2000, and for this reason it is an available name as Microparasellidae Karaman, 1934. The family name Microparasellidae is then valid.

Conversely, we provisionally maintain current and common usage of the names Microparasellus and Microcharon, and this is discussed in more detail together with a new diagnosis for the Microparasellidae (see Appendix 1). As the nomenclature within the family Microparasellidae is well established and widely used, a proposition (Galassi and Bruce in preparation) will be submitted to the ICZN Commission for maintaining the stability of the current nomenclature and related authorities.

Lepidocharon priapus Galassi & Bruce, sp. n.; here designated.

Lepidocharon lizardensis Galassi & Bruce, sp. n.

Male. Body slender, 8.5–9.7 as long as wide. Free pleonite narrower than pereionites and pleotelson, visible in dorsal view. Cephalon medio-frontal margin not produced, anterior margin straight, rostrum absent. Pereionites 1–3 anteriorly widest, with distinct anterolateral angle, pereionite 4 sub-rectangular, pereionites 5–7 posteriorly widest, lateral margin with distinct posterolateral angle. Pereionites dorsally ornamented by paired setae. Cuticle with small semicircular thickening present or absent both dorsally and ventrally. Antennula 6-segmented; long aesthetascs on articles 5 and 6, long brush seta on article 2 extending to tip of article 6. Antenna with 6 podomeres; article 3 with long blade-like or candle flame-like scale, reaching article 5; lateral margin with 2 setae; flagellum with 8–12 articles.

Mandible palp article 1 unarmed, article 2 with 2 stiff spinulose setae, article 3 with 5 stiff spinulose setae. Right mandible: incisor with 6 to 9 cusps; lacinia mobilis absent; molar process conical, with 3 setae. Left mandible: incisor with 2 to 3 cusps; lacinia mobilis present and produced in 2 cusps; molar process conical, with 3 setae. Maxillula: mesial lobe slender and tapering at distal part, bearing 1 short apical seta accompanied by subapical shorter setae and lateral thin and short setae. Lateral lobe sub-rectangular in shape. Apical setation composed by a variable number of setae. Maxilla: mesial ramus with 8–9 setae; 1 apical comb-like seta, strong, unipinnate and ornamented with fine regularly-spaced setules parallel to one another. Lateral rami close-set, each bearing 4 slender and simple setae, respectively. Maxilliped palp wider than endite, mesial margin of articles 2 and 3 expanded. Pereiopods all subequal in length, all subsimilar in size and general morphology; all with 2 dactylar claws; pereiopod 1 dactylar claws subequal; pereiopods 2–7 superior claw slender (3.8–4.3× basal width), inferior claw robust (2.3–2.6× basal width). Coxae rudimentary reduced to small sclerites, not discernible in dorsal view, coalescent to body wall of the sternites, located on the anterior margin of the concavity which houses the propodus, and apparently not articulated to the sternites.

Pleotelson 1.3–1.7 as long as wide, 1.7–1.9 as long as pereionite 7. Penial papillae opening on postero-medial margin of sternite 7. Pleopod 1 rami proximally fused; proximolateral margins with cuticular imbricate scales on posterior side; distolateral margins convex; stylet-guiding groove represented by a folded hyaline lamella running sub-parallel to free lateral margin of rami; pleopod 1 transverse stylet-guiding grooves absent, unlike Janinella. Pleopod 2 stylet long and slender, of variable length. Pleopod 3 endopod bearing 3 distal plumose setae; exopod elongate, lateral margin with thin setae, article 2 with 1 subapical seta; pleopod 4 rudimentary, ovoid, uniramous. Uropodal protopod as long as the pleotelson, slender (length/width ratio: 4.3), not sexually dimorphic, with long and slender exopod and endopod.

Female. As for the male, except for sexual characters. Operculum (pleopod 2) longer than broad, with surface smooth or with semicircular thickening, with distal margin faintly incised, and 4 apical setae.

The generic name is derived from the ancient Greek name λεπις, λεπιδος meaning “scale”, which refers to the unique rim of scale-like elements bordering the proximal part of the first male pleopod on the posterior side, combined with the mythological name Charon, Charontis referring to the Ferryman of Hades. Gender: masculine.

Lepidocharon gen. n. is most similar to the genus Microcharon, the two genera sharing the following characters: well-developed uropods with slender endopod and exopod; pereiopodal coxal plates not discernible in dorsal view, small, incorporated to the sternite body wall; male pleopod 1 with similar general organization, the distal lateral lobe with a folded hyaline lamella (stylet-guiding groove) running almost parallel to the lateral margins of the pleopod (this orientation and structure of the stylet-guiding groove appears different from that of Janinella, where a transversal and oblique groove hosts the stylet of the male pleopod 2 which seems not to be enveloped by a hyaline lamella); pleopod 2 identical in the development of both exopod and endopod, the latter ending with a stylet of different length depending on the species; penial papillae small and located at the posteromesial margin of sternite 7; female operculum as long as the pleotelson, faintly incised, bearing 4 apical setae (a condition shared by some predominantly marine, and rarely freshwater, Microcharon species).

Lepidocharon gen. n. shares with Janinella the morphology of the tergites, the first three pereionites with antero-lateral protrusions, the fourth sub-rectangular in shape, and the last three postero-laterally protruded, together with the lateral insertion of pereiopods 1–7 oriented outwards (vs. ventrally in Janinella, see Albuquerque et al. 2014); pereiopodal coxal plates small in Janinella, very reduced and incorporated to body wall in Lepidocharon gen. n. The female operculum of Lepidocharon is more than twice as long as wide, as long as the pleotelson, only faintly incised and bearing 4 apical setae, the mesial pair being close-set. These apical setae resemble that of Janinella species, where only the two close-set setae are present.

Lepidocharon gen. n. differs from all the other lepidocharontid genera by the combination of the following morphological characters: (1) the unique presence of scale-like elements bordering the postero-lateral margins of the proximal part of the male pleopod 1; (2) pereionites with coxal plates hardly discernible, small, and incorporated into the sternite body wall, not visible in dorsal and lateral views; (3) the long and slender pereiopods that are inserted laterally and directed outwards; (4) pereionites that are not cylindrical, except pereionite 4 (vs. cylindrical in Microcharon); (5) the presence of elongate antennal scale (vs. rudimentary in Janinella, and generally reduced in Microcharon); (6) the mandible incisor with up to 9 cusps (lower number of cusps in Microcharon and Janinella).

Microcharon galapagoensis Coineau & Schmidt, 1979 is closer to Lepidocharon gen. n., especially in the general body morphology, pereionite shape, slender pereiopods directed outwards, a long antennal scale, and slender and elongate uropods; however the unique scale-like elements of the male pleopod 1 of Lepidocharon are not present in this species. These scales are not easily detected under optical microscopy (if not at 100× magnification), nor were they seen using SEM because located on the posterior side of the pleopod.

The mid-section of the male pleopod 1 shows lateral margins expanded in both species of Lepidocharon gen. n. In contrast to the new genus, M. galapagoensis shows a 5-segmented antennula. Coineau and Schmidt (1979) had informally proposed the creation of an intermediate group between the genus Microcharon and Janinella (formerly Paracharon Coineau, 1970) for M. galapagoensis Coineau & Schmidt, 1979 (from marine interstitial habitats in the Galapagos), M. salvati Coineau, 1970 (from coral sands in New Caledonia) and M. herrerai Stock, 1977 (from brackish groundwater in the Netherlands Antilles) (Stock 1977).

Holotype here designated. Adult ♂ (1.3 mm) completely dissected and mounted in polyvinyl lactophenol on one slide (MTQ W28329), 17 February 2009, coll. N.L. Bruce and M. Błażewicz-Paszkowycz.

Type-locality: Australia, Great Barrier Reef, off Coconut Beach, Lizard Island, reef front, sand adjacent to bommies, 4 m, stn LIZ 09–09A, 14.68441°S, 145.47197°E.

Paratypes. 2 ♂♂ (0.9, 1.1 mm), 2 ♀♀ (1.1, 1.4 mm), Great Barrier Reef, Australia, completely dissected and mounted in polyvinyl lactophenol; 2 ♂♂, 1 ♀, same data as holotype preserved in alcohol; 1 ♂, 1 ♀ mounted on SEM stubs (all MTQ W30933).

The epithet is derived from the god Priapus (Πρίαπος) of the Greek mythology. He was considered the protector of livestock, fruit plants, gardens and male genitalia. He was famous for his largely phallic character and the specific names is here referring to the extraordinary length of the stylet of male pleopod 2.

Body length, measured from tip of cephalon to end of pleotelson, from 0.9 to 1.3 mm (n=6). Body 7.0–8.0 times longer than wide, dorsally flat. Cephalon (Fig. 1A) longer than wide (length/width ratio: ~1.3), as large as pereionites, lateral margins sub-parallel. Pereionites 1–3 with anterolateral margins of tergites protruding; pereionite 4 rectangular, without tergite protrusions, pereionites 5–7 with posterolateral margins of tergites protruded. Pereiopods inserted close to lateral closure of tergites (Figs 1A, 2G–H) and extended outwards, coxal plates not discernible on dorsal and lateral views, small, totally incorporated to the border of the concavity housing the pereiopods (Fig. 2D, G–H).

Paragnaths (Fig. 3C) large, free distal margin with long slender simple setae and marginal and submarginal rows of scale setae. Labrum ovoid (Fig. 3D), ornamented with fine spines on free anterior margin.

Antennula (Fig. 1B) composed of 6 articles; article 1 1.5 as long as wide, directed anteriorly, with 2 simple setae; article 2 1.5 as long as wide, 0.8 as wide and 0.8 as long as article 1, with 4 setae inserted at distal third of article, 2 of which penicillate setae plus 1 long penicillate seta inserted on a lateral protrusion of article, accompanied by a short and thin naked seta on its basis; article 3 unarmed; article 4 with 1 lateral seta and 2 surface penicillate setae; article 5 shorter than article 4, bearing 1 long aesthetasc and 1 simple seta at basis of aesthetasc-bearing protrusion; article 6 short, 0.5 as long as article 5 and clearly articulated with article 5 (Fig. 2A), bearing 5 setae in total, two surface seta (one of which penicillate), one apical and one subapical simple setae; one long aesthetasc and a robust and long seta apically, both incorporated to article 6.

Antenna (Fig. 3A–B) with 6 podomeres, 2 proximal articles short and stout, article 1 with 1 apical outer seta; article 2 naked; article 3 robust, length/width ratio: 1.25, with mesial apical seta and long exopod quite overreaching segment 4, knife-blade shaped and bearing 2 long and thin setae inserted on lateral margin at middle of exopod; article 4 stout and curved outward, 0.5 as long as article 3, with 2 apical mesial setae; articles 5 and 6 slender and long, article 6 longest, bearing 6 and 10 simple setae, respectively; flagellum composed of 9 articles in holotype; 11 articles in one male paratype; all flagellar articles with distal hyaline lamella partially covering insertion of following article, all armed with setae on distal margin, except article 9 ending with 3 simple and 1 penicillate setae.

Mandible palp (Fig. 3E) on short cuticular projection; palp article 1 without setae, article 2 longest, about 2.5 times longer than wide, with 2 pinnate robust setae laterally, their insertion more or less coalescent with article; article 3 curved laterally, with 5 pinnate robust setae, distalmost seta longest; 2 cuticular comb rows on lateral margin of article. Left mandible (Fig. 3E): incisor with two strong and large cusps; lacinia mobilis as in the genus; molar process with two long unipinnate setae accompanied by 1 short simple spine. Between lacinia mobilis and molar process 3 thin, long and simple spines and 3 unipinnate spines are present, 1 modified seta, cockscomb-shaped, close to lacinia mobilis, with total of 7 elements. Right mandible (Fig. 3F) incisor with 6 robust cusps; 2 long unipinnate and 1 short simple seta. Between incisor and molar process 6 spines are inserted, apicalmost robust, curved and unipinnate, 3 naked and 2 unipinnate spines.

Maxillula (Fig. 4A): mesial lobe slender and tapering at distal part bearing 1 short apical seta accompanied by 2 subapical shorter setae and two lateral thin and short setae. Lateral lobe sub-rectangular in shape, bearing scale-like elements on both lateral and mesial margins. Apical setation composed by 11 elements; 3 simple setae in subapical position (surface apical setae); 2 mesial setae with apical tuft; remaining 6 distal setae unipinnate.

Maxilla (Fig. 4B): mesial ramus with 9 setae, 3 naked and slender setae on mesial margin, 1 surface seta short; 5 apical setae, mesialmost and 3 lateralmost apical setae simple and slender; second apical setae (starting from mesial margin) comb-like, strong, unipinnate and ornamented with fine regularly-spaced setules parallel to one another. Lateral rami close-set, each bearing 4 slender and simple setae, respectively.

Maxilliped (Figs 4C, D, 2B, C): palp robust and curved inwards; article 1 sub-rectangular in shape, bearing 1 mesial and 1 lateral setae; article 2 longest, robust, rounded on mesial margin, with 2 setae at distomesial angle; article 3 shorter than article 2 with 1 distolateral and 3 mesial setae; article 4 angled mesially, with 1 seta on distolateral margin, 1 seta on mesial margin and 3 setae on distal margin; article 5 about 0.5 as long as article 4, with 8 apical setae, of which 6 are simple slender setae and 2 are stiff pectinate setae. Endite almost reaching end of palp article 2; mesial margin ending in a pointed protrusion, with numerous hair-like setules and 2 coupling hooks medially; apical free distal margin with 4 bipinnate, spine-like, stout setae and 1 simple non-tapered seta; 3 subapical fan setae are present; epipod ovoidal, reaching distal part of palp article 1.

Pereiopod 1 (Figs 2E, 4E): coxal plate hardly discernible, basis slightly enlarged, relatively short in comparison to length of same segment of pereiopods 2–7, with 3 short setae, one of which is a penicillate seta; 2 opposite setae on ischium, transformed in sensorial penicillate setae; merus trapezoidal, shorter than all other articles, bearing 4 long and large setae on mesial and lateral apical margins; carpus longer than merus bearing 2 opposite long slender setae; mesiodistal margin with spinule row; propodus longer and slender than merus, ending with a small sclerite (Fig. 2E), with mesial hyaline lamella, bearing 1 bifid robust seta and 5 slender setae; dactylus with 6 slender sensorial setae, 3 of which inserted on surface of dactylus at base of insertion of longer claw, 2 surface setae inserted at basis of shorter claw, 1 seta on mesial distal margin of dactylus. Pereiopods 2–7 with strong dactylar claws with rounded tip. Morphology, relative length of pereiopodal segments and their armature apparently identical. Pereiopods 2–7 (pereiopod 7 figured; Fig. 5A) with coxal plate hardly discernible, basis slender than in pereiopod 1, bearing 4 setae, 2 of which penicillate, and 2 not transformed slender setae; ischium longer than in pereiopod 1, rectangular in shape, bearing 3 setae, 2 of which penicillate; merus shorter than articles, trapezoidal, and stouter than in pereiopod 1, bearing 1 sensorial seta on mesial margin, and 2 robust spiniform setae on apical mesial and lateral margins, respectively; a pointed protrusion discernible on mesial margin in subapical position accompanied by 1 thin seta; carpus longest; longer than both merus and propodus, bearing 4 elements; 1 proximal mesial simple seta and 1 bifid spine; 2 lateral setae located on apical lateral margin, 1 of which thin and long, the latter transformed in a penicillate seta; propodus long and slender than carpus, ending with elongate sclerite (Fig. 2F), bearing 2 bifid stout spines on mesial margin and 4 simple thin setae of different lengths; dactylus ending with two stout claws subequal in length, armed with 5 thin setae likely with sensorial function, 3 of which inserted on surface of dactylus at base of the insertion of longer claw, 2 surface setae inserted at basis of shorter claw.

Pleonite 0.29 as long as and 0.84 as wide as pereionite 7 (Figs 1A, 6A), small, narrower and shorter than pereionites and pleotelson; well discernible on dorsal and ventral views, partially covered by pereionite 7 on ventral view (Fig. 6A).

Penial papillae, as for the genus, coalescent and located at the middle of the free posterodistal margin of pereionite 7, with undulated free outer margins and a medial channel (Fig. 6A–B).

Pleotelson 1.37 as long as maximal width (Figs 8D, 15A), longer than wide (length/width ratio: from 1.75 to 2.00, n = 5). Dorsal side with semicircular thickening, as dorsal and ventral body surfaces; with 4 dorsal setae, arranged in two pairs; lateral margins each bearing 3 slender setae. Pleotelson distal margin with 12 marginal setae, inserted in apical or subapical position; 2 of them are penicillate setae.

Male pleopods 1 elongate and slender, fused proximally, with sperm tube medially with an anterior opening ornamented by small spines (Figs 5B, 6A, C), approximately 3.3 as long as maximum width (measured at widest section of proximal part of pleopod). Proximal part of pleopod large and gradually tapering at distal part, bordered by paired rows of 10 imbricate scale-like elements on posterior surface. Middle part of pleopod with free lateral margins smooth, parallel, and slender, ending with convex rounded margins, tapering apically, with paired well-developed distal protrusions, each ending with rounded apex, a hyaline membrane, crenulated on lateral margin, and smooth on mesial margin. Stylet-guiding groove parallel to lateral margins of pleopod, and folded by hyaline lamella, sclerotized in terminal part on both lateral and mesial sides of distal part of pleopod. Distal part of pleopod with 7 setae.

Male pleopod 2 (Fig. 7A): protopod elongate, sub-rectangular at its proximal part, and with rounded mediodistal corner; surface of protopod with semicircular thickening (Fig. 7B), exopod extruding partially from distal part of protopod, appendix masculina (endopod) extraordinarily long, more than 3 times (3.0–3.3; n = 4) the protopod length, ending with a long stylet with a sclerotized rib that runs along its entire length; terminal part with inflated lateral margins tapering to an acute tip. Stylet quite overreaching distal part of protopod, and reaching in length distal part of uropods.

Pleopod 3 (Fig. 7C, D) with endopod bearing 1 apical, 1 mesial subapical and 1 lateral plumose setae; exopod 2-segmented, with setulose hyaline lamella on lateral margin; exopod 1 elongate, 2.8 times longer than exopod 2, the latter ending with short simple seta.

Pleopod 4 (Fig. 8A) rudimentary, ellipsoidal, uniramous.

Uropods long and slender (Fig. 8B), approximately two times longer than pleotelson. Protopod long, two times longer than endopod. Exopod and endopod long and slender; endopod longer than exopod, the latter inserted in subapical position on protopod. Mesial margin of protopod armed with 5 setae; lateral margin with 8 setae, 8 surface setae, 4 of which are slender and located on ventral surface, remaining setae on dorsal surface large. Endopod with long setae on distal third, 6 of which are penicillate setae, remaining 7 setae slender, simple, with rounded tip. Exopod armed with 9 setae on distal third, all of which slender; apicalmost setae longest.

Body length generally similar to male (Fig. 15A). Body length measured from tip of cephalon to end of pleotelson from 0.9 to 1.4 mm. (n = 3). Length/width ratio: ~8.5. Female operculum elongate (Figs 6D, 8C), sub-rectangular in shape, with parallel lateral margins, proximal margin straight; distal part medially incised, bearing 2 close-set short medial setae and 2 setae in apical lateral position. Operculum surface with semicircular thickening (Fig. 6D).

Detailed comparison between the two species is given in the remarks for Lepidocharon lizardensis sp. n.

Holotype here designated. Adult ♂ (1.1 mm), completely dissected and mounted in polyvinyl lactophenol on one slide, 17 February 2009; coll. N.L. Bruce and M. Błażewicz-Paszkowycz (MTQ W28330).

Type-locality: Australia, Lizard Island, off Coconut Beach, 14.68441°S, 145.47197°E, reef front, sand adjacent to bommies, 4 m, stn Liz 09-09A.

Paratypes. 1 ♂ (0.9 mm), 1 ♀ (1.2 mm) completely dissected and mounted in polyvinyl lactophenol, same data as holotype (all MTQ W28331).

The epithet lizardensis is after the type locality, Lizard Island, northern Great Barrier Reef, Queensland.

Body length measured from tip of cephalon to end of pleotelson 0.9–1.1 mm (n = 2). Body dorso-ventrally flattened, stocky, small-sized, about 6.5 times longer than wide (Figs 9A, 15B). Cephalon as long as wide (length/width ratio: ~1), as large as pereionites, lateral margins sub-parallel; anterior margin not projecting, rostrum absent. Dorsal surface of cephalon, pereionites and pleotelson (except free pleonite) ornamented with dorsal setules, arranged symmetrically and in pairs (Fig. 9A).

Pereionites 1–7 subequal in width (Fig. 9A); pereionites 1–3 with anterolateral margins of tergites only slightly protruding; pereionite 4 rectangular, without protrusions, pereionites 5–7 with posterolateral margins of tergites slightly protruded. Pereiopods inserted on lateral margins of tergites, visible in dorsal view (Fig. 9A); coxal plates rudimentary, incorporated to sternites.

Paragnaths (Fig. 9B) consisting of 2 large rounded lobes, deeply incised on medial side, ornamented with long setules on free mesial margins; thin simple setae are accompanied by small setules. Lateral margins with three short spinule rows. Labrum ovoid (Fig. 9C), with free anterior margin convex and medially thickened, with pair of thin scale-setae inserted symmetrically on the outermost sides of the free distal margin.

Antennula (Fig. 9D) composed of 6 articles; article 1 broadest, 1.6 as long as wide, directed anteriorly, with 2 simple and 2 penicillate setae; article 2 narrow, 1.6 as long as wide, 0.6 as wide and 0.7 as long as article 1, with 5 setae inserted at distal third of article, two of which penicillate; 1 long sensorial aesthetasc-like seta inserted on lateral protrusion, accompanied by a short and slender simple seta on its basis; article 3 unarmed; article 4 with 1 lateral simple seta and 2 penicillate setae inserted in apical position; article 5 slightly shorter (0.86) than article 4, bearing 1 long aesthetasc and 1 simple long slender seta at base of aesthetasc-bearing protrusion; 2 simple setae inserted at surface of article; article 6 very short, clearly articulated with article 5, bearing 2 subapical lateral setae, one of which aesthetasc-like penicillate seta, and 1 long apical seta close to 1 long aesthetasc and 1 subapical slender seta between them.

Antenna (Fig. 10A–B): with 6 podomeres, articles 1 and 2 short, article 1 with mesial seta; article 2 with short lateral seta; article 3 robust, with mesial apical seta and long exopod overreaching segment 4, candle-flame shaped and bearing 2 short and slender setae inserted at middle of exopod; article 4 stout and curved with 2 apical mesial setae; articles 5 and 6 slender, article 6 longest, bearing respectively 7 and 12 armature elements, 5 of which transformed in penicillate setae with apical tuft; flagellum composed of 12 articles, all flagellar articles with setae on distal margins, most setae simple; some on flagellar articles 1 and 4 are penicillate setae.

Mandible. Palp (Fig. 10C) on short cuticular projection. Palp article 1 naked, article 2 longest, about 2.5 times as long as wide, with 2 pinnate robust setae laterally, their insertion more or less coalescent with article; article 3 curved laterally, with 4 spinulose and 1 apicalmost unipinnate setae, distalmost longest and stout; 2 setule rows on lateral margin of article. Left mandible (Fig. 10D): incisor with 3 cusps; lacinia mobilis with 2 teeth; molar process with 2 long unipinnate spines and 1 short smooth seta. Between lacinia mobilis and molar process 2 transformed crested setae are present; 6 slender, long simple setae complement total pattern of 8 elements. Right mandible (Fig. 10E) incisor with 8 robust cusps; molar process with 3 apical spines, 2 of which unipinnate and robust, proximalmost naked and shorter; between incisor and molar process 6 spines are inserted, proximalmost curved, robust and uniserrate; remaining spines simple.

Maxillula (Fig. 11A) with slender mesial lobe tapering at distal part bearing 1 short apical seta accompanied by secondary subapical short seta and hair-like setules. Lateral lobe sub-rectangular in shape, bearing scale-setae on both lateral and mesial margins. Apical setation composed of 13 elements; 1 mesial slender seta, 1 mesialmost apical seta with bifid tip; 1 penicillate seta, 7 uniserrate setae, and 3 subapical surface simple setae.

Maxilla (Fig. 11B) mesial ramus with 8 setae, 2 naked setae on mesial margin, 6 apical setae, mesialmost naked, 1 uniserrate, third seta comb-teeth shaped, unipinnate, ornamented by fine setules regularly spaced and parallel to one another; remaining 3 setae simple. Lateral rami close-set, each bearing 4 setae of different lengths; lateralmost ramus with 3 spinulose and 1 short mesial setae.

Maxilliped (Fig. 11C–D) palp robust and curved mesially; article 1 sub-rectangular in shape, bearing 1 lateral and 1 mesial short setae; article 2 robust, bearing 1 apical mesial seta; article 3 as long as article 2, with 1 lateral apical and 3 mesial setae inserted on mesial margin; article 4 curved inwards, slender, with 1 lateral and 4 apical setae inserted at boundary line between article 4 and 5; article 5 short and narrow, with 2 apical and 3 subapical setae, of which 3 are simple slender setae of different lengths and 2 are robust and large, stiff pectinate setae. Endite almost reaching end of palp article 2; mesial margin ending in pointed protrusion, with numerous hair-like setules and 2 coupling hooks mesially; apical free distal margin with 3 spine-like, serrate setae, 1 simple non-tapered seta, and 2 surface fan setae; epipod ovoidal, overreaching distal part of palp article 1, bearing 1 subapical short, minute seta (this seta not found in other specimens).

Pereiopod 1 (Fig. 11E) coxal plate hardly discernible; basis slightly enlarged, shorter than that of P2–P7, with 2 short setae on mesial surface and 1 short simple seta on distolateral margin, and 2 penicillate setae; 2 opposite setae on ischium, one of which longer, a tubular sensorial seta on surface; merus shorter than other articles, trapezoidal, bearing 3 long setae; carpus slender and longest, mesial margin with 2 thin setae; distolateral margin with 1 simple slender seta and 1 penicillate seta; propodus slender than carpus, ending with a small elongate sclerite, with 2 mesial slender setae and 1 bifid spiniform seta; spinule row on free distal mesial margin; 3 simple setae on anterior surface; a spinule row at insertion of bifid spine; dactylus with 4 thin sensorial setae, inserted in pairs at base of each claw. Pereiopods 2–7 (pereiopod 7 figured; Fig. 12A) with coxal plate rudimentary and incorporated to the sternite, basis slender than in pereiopod 1, bearing 5 setae, three of which penicillate and two slender simple setae; ischium slightly longer and slender than in pereiopod 1, rectangular in shape, bearing 3 setae, 1 of which transformed in penicillate seta; merus shorter than all other leg segments, trapezoidal, and slightly longer and slender than in pereiopod 1, bearing 2 setae on mesial margin, 1 robust seta on apical lateral margin and 1 slender simple seta on surface at boundary between merus and carpus; carpus almost as long as propodus; robust, bearing 1 simple thin seta and a bifid spine along mesial margin, and 2 short thin setae on lateral margin, a penicillate seta inserted close to apicalmost lateral seta; propodus slender than carpus, with small elongate sclerite, bearing 2 bifid stout spine-like setae on mesial margin, 2 surface simple setae of different lengths and a surface penicillate seta at distal third of article; dactylus ending with 2 strong claws with rounded tip, slightly subequal in length, lateral claw slender, mesial stouter and shorter; dactylus armed with 5 thin setae likely with sensorial function, 3 of which inserted at surface of article, at base of insertion of the longer claw, 2 surface setae inserted at basis of shorter and stouter claw.

Pleonite length 0.27 pereionite 7 length, width 0.86 pereionite 7 width (Figs 9A, 14A, 15B).

Pleotelson longer than wide (Fig. 14A, 15B) (length/width ratio: from 1.33 to 2.00, n = 2). Dorsal side with 6 setae, a pair located on proximal part of pleotelson, other 2 pairs of setae arranged in close-set two pairs, both pairs located on distal third of pleotelson. Lateral margins bearing 3 slender setae at each side; 16 setae bordering free distal margin of pleotelson, inserted in apical or subapical position; 4 of them are penicillate setae.

Male pleopods 1 (Fig. 12B) elongate, coalescent in proximal part, with sperm tube medially, length about 4.5 times longer than maximum width (measured at widest section of proximal part of pleopod). Proximal part of pleopod large and gradually tapering at its distal part, bordered by paired rows of 4 scale–like elements. Middle part of pleopod with free distal margins smooth, parallel and slender, ending with slightly inflated sub-distal rims, tapering in apical part with paired well-developed sub-rounded bilobate tips. Stylet-guiding groove folded by hyaline lamella, running parallel to lateral margins of pleopod, only slightly sclerotized and ending with a transversal straight margin. Set of distal setae composed by 6 elements only.

Male pleopod 2 (Fig. 13A): protopod elongate, sub-rectangular at proximal part, with rounded mediodistal corner; exopod protruding from protopod at middle of mesial margin, appendix masculina (endopod) stylet ending with skewed apex, opening oblique; stylet short, shorter than and not reaching distal part of protopod.

Pleopod 3 (Fig. 13B–C) exopod bearing 1 apical plumose seta, 1 lateral subapical medial long plumose seta and 1 subapical mesial plumose seta. Between mesial and apical setae exopod is protruded in rounded or bilobate lobes (Fig. 13B–C); endopod with setulose hyaline lamella on mesial margin bordered by fine setule row; endopod 1 elongate, about 2.2 longer than endopod 2, the latter ending with short simple subapical seta.

Pleopod 4 (Fig. 13D) rudimentary, ellipsoidal, uniramous.

Uropods unknown.

Body length approximately as in male. Body length measured from tip of cephalon to end of pleotelson 1.2 mm. No sexual dimorphism observed in body morphology, cephalic appendages and pereiopods. Female operculum (pleopod 2) elongate (Fig. 14B), sub-ovoid, with rounded lateral margins, proximal margin straight; distal margin with medial incision, with 2 close-set short medial setae very close to medial incision and 2 longer apical setae in lateral position. Operculum surface smooth. Uropods unknown.

Lepidocharon priapus and L. lizardensis differ from each other in several characters: 1) the morphology of the antennal scale (blade-knife shaped in L. priapusvs. candle-flame shaped in L. lizardensis); 2) the slender body with different degree of protrusion of the pereionites 1–3 and 5–7 (markedly protruded in L. priapus vs. stouter and less protruded in L. lizardensis); 3) the different shape of the male pleopod 1 (with strongly protruded and pointed apical lobes and sclerotized hyaline lamella in L. priapus vs. sub-rounded and undulated apical lobes and a tiny hyaline lamella in L. lizardensis); 4) the setal complement of the male pleopod 1 (7 in L. priapus vs. 6 in L. lizardensis); 5) the morphology of the male pleopod 2 (sub-rectangular and long protopod with endopodal stylet extraordinarily long, reaching the tips of the uropods in L. priapus vs. ovoidal protopod with a short stylet, not reaching the distal part of the protopod in L. lizardensis); 6) female operculum sub-rectangular in shape, with straight lateral margins in L. priapus vs. oval, with convex lateral margins in L. lizardensis); 7) a rounded pleotelson in L. priapus (sub-truncate in L. lizardensis), and 8) body surface with visible semicircular thickening in L. priapus (smooth in L. lizardensis).

Body slender, 4.0–6.0× long as wide, somites all subsimilar in width, head with acute or narrowly rounded rostrum. Lateral margins of head and pereionites convex, with cuticular scales; pleonite 1 laterally free; body without chromatophores. Eyes absent. Antennula flagellum with maximally 4 articles. Antennal scale absent. Antenna flagellum shorter than podomeres. Mandibular molar process distally pointed, without grinding surface, with several terminal setae. Pereiopods 1–7 not chelate or subchelate, almost identical in shape; all pereiopods with 2 dactylar claws. Pereiopods articulated latero-ventrally. Penial processes present, coalescent, with single medial opening on posterior margin of pereionite 7. Pleopods 1 and 2 not operculate in males; female pleopod 2 operculate; pleopod 3 endopod unarmed, exopod slender. Uropods uniramous, minute, stub-like, insertion ventro-terminal; single ramus, shorter than protopod. Anus terminal, not covered by pleopods.

The family Microparasellidae was ambiguously established by Karaman (1933) without formally stating family name anywhere in that publication. On the same occasion, the author described two new species of Microparasellus, namely Microparasellus puteanus Karaman, 1933 and Microparasellus stygius Karaman, 1933, but without designation of the type species for the genus Microparasellus, and without providing the name of the new family. One year later, Karaman (1934) formally proposed the family name Microparasellidae for the new family, also giving a family diagnosis and assigned two genera to the family: the then monotypic Microparasellus Karaman, 1933 (Microparasellus puteanus) and transferring Microparasellus stygius Karaman, 1933 to the new genus Microcharon Karaman, 1934 together with Microcharon latus Karaman, 1934 described in the same paper (Karaman 1934).

Microparasellus puteanus Karaman, 1933. Type locality: Skopje, Macedonia. Karaman (1934) formally described the family Microparasellidae, at the same time establishing the genus Microcharon Karaman, 1934. At that point Karaman restricted the genus Microparasellus to the single species M. puteanus. This in itself does not constitute a subsequent type species designation, and Karaman’s (1934) intention was clearly not to do that as he equally did not designate a type species for Microcharon (this was a common practice at that time).

Microparasellus libanicus Chappuis & Delamare Deboutteville, 1954, Lebanon; Microparasellus aloufi Coineau, 1968, Lebanon; Microparasellus hellenicus Argano & Pesce, 1979, Greece.

The generic name Microparasellus established by Karaman (1933) is not an available name because, even though a diagnosis has been given, the type–species was not designated for the genus. This course of action makes the name unavailable under the provisions of the ICZN (1999: Article 67.4.1 which states: “A nominal genus-group taxon stablished after 1930 (or, in the case of an ichnotaxon, after 1999 [Art. 66.1]) must have its type species fixed in the original publication [Art. 13.3]”. As the nomenclature within the family Microparasellidae is well established and widely used, a proposition to the ICZN Commission is needed for maintaining the stability of the nomenclature and related authorities. The same situation exists for the genus Microcharon Karaman, 1934, now placed in the new family Lepidocharontidae. This state of affairs, along with the minimal standard of species descriptions, would require a detailed re-examination of the Microparasellus as a whole. Pending this procedure, authorities and dates of common use are hereby maintained.

The Microparasellidae can be regarded as monophyletic as here defined. While we do not enter a discussion into monophyly or otherwise of the Janiroidea, it is apparent, as shown by Wilson’s (1994) analysis, that the Microparasellidae lacks the characteristic operculate pleopods shown by the Janiroidea.

Species of the family are known from North Africa and eastern Europe only.