﻿Rhagophthalmidae Olivier, 1907 (Coleoptera, Elateroidea): described genera and species, current problems, and prospects for the bioluminescent and paedomorphic beetle lineage

﻿Abstract Rhagophthalmidae are a small beetle family known from the eastern Palaearctic and Oriental realms. Rhagophthalmidae are closely related to railroad worms (Phengodidae) and fireflies (Lampyridae) with which they share highly modified paedomorphic females and the ability to emit light. Currently, Rhagophthalmidae include 66 species classified in the following 12 genera: Bicladodrilus Pic, 1921 (two spp.), Bicladum Pic, 1921 (two spp.), Dioptoma Pascoe, 1860 (two spp.), Diplocladon Gorham, 1883 (two spp.), Dodecatoma Westwood, 1849 (eight spp.), Falsophrixothrix Pic, 1937 (six spp.), Haplocladon Gorham, 1883 (two spp.), Menghuoius Kawashima, 2000 (three spp.), Mimoochotyra Pic, 1937 (one sp.), Monodrilus Pic, 1921 (two spp. in two subgenera), Pseudothilmanus Pic, 1918 (two spp.), and Rhagophthalmus Motschulsky, 1854 (34 spp.). The replacement name Haplocladongorhami Kundrata, nom. nov. is proposed for Diplocladonhasseltii Gorham, 1883b (described in subgenus Haplocladon) which is preoccupied by Diplocladonhasseltii Gorham, 1883a. The genus Reductodrilus Pic, 1943 is tentatively placed in Lampyridae: Ototretinae. Lectotypes are designated for Pseudothilmanusalatus Pic, 1918 and P.marginalis Pic, 1918. Interestingly, in the eastern part of their distribution, Rhagophthalmidae have remained within the boundaries of the Sunda Shelf and the Philippines demarcated by the Wallace Line, which separates the Oriental and Australasian realms. This study is intended to be a first step towards a comprehensive revision of the group on both genus and species levels. Additionally, critical problems and prospects for rhagophthalmid research are briefly discussed.


Introduction
described the morphology of a larviform adult female of Rhagophthalmus. He also erected Menghuoius Kawashima, 2000 for two Chinese species originally classified in Rhagophthalmus, and later described the third species of that genus from Myanmar (Kawashima 2000(Kawashima , 2002. Kawashima and Satô (2001) described three species of Rhagophthalmus from Myanmar, Taiwan, and Thailand, and Kawashima and Sugaya (2003) added an additional new species from Taiwan. Branham and Wenzel (2003) studied the evolution of bioluminescence in the softbodied elateroids (i.e., "cantharoids") and confirmed that Rhagophthalmus is closely related to Dioptoma and Diplocladon. Li and Liang (2008) described the morphology of a larviform adult female of Diplocladon from China. Li et al. (2008a) described two new species of Rhagophthalmus from China, provided information on the morphology and distribution for several other species, and provided a distribution map for all species in China and surrounding regions.
Despite the long history of rhagophthalmid systematic research, we lack a comprehensive study which would summarize all relevant information of all genera and species in the group. Therefore, in this study, we provide an annotated catalogue of genera and species of Rhagophthalmidae, including information on their synonyms, type material, distribution, and bibliography. We believe this study will serve as a robust framework for subsequent taxonomic revisions of all genera in addition to studies devoted to diversity, evolution, nature conservation, and ecology of the group.
Remarks. As defined here, Rhagophthalmidae include 12 genera (one of them with two subgenera) and 66 species distributed primarily in East, South, and Southeast Asia, with a few species found on the border of South and Central Asia (i.e., Afghanistan). Males can be recognized by antennae with 12 antennomeres, with antennomere III longer than antennomere II. In cases where the antennae are serrate or pectinate, antennomere III is not simple, i.e., the serration or rami begin on antennomere III. Females are more (e.g., Diplocladon or Haplocladon; see Remarks under these genera) or less (e.g., Rhagophthalmus) larviform (for more information, see Kawashima et al. 2010). Known larvae are predators of millipedes, similar to larvae of the closely related Phengodidae. Although Rhagophthalmidae were credited by McDermott (1966) to "Olivier, 1902", we found no evidence of the publication to which McDermott referred, similar to Lawrence and Newton (1995: 858).
Remarks. This genus currently contains two described species from Borneo and Sumatra, respectively. It is similar to Bicladodrilus and Diplocladon in having strongly bipectinate antennae and long elytra. This generic complex is in need of revision. Pic, 1930  Remarks. Pic (1930a: 5) also reported an unnamed variety of B. mjobergi based on a specimen from Tjinta Radja. This specimen is deposited in SMNH and bears the label "Typus"; however, based on Article 72.4.1. of the Code (ICZN 1999) it should not be considered a part of the type series. Pic, 1921 Bicladum multipunctatum Pic, 1921b: 12. Type depository. Described based on an unknown number of specimens. Syntype, male (MNHN).
Remarks. This genus currently contains two described species from Bangladesh, India, and Sri Lanka. Males are characterized by short antennae and deeply emarginate eyes, each with a smaller upper portion and a larger lower portion (Fig. 1B). Regarding the gender of Dioptoma, Pascoe (1860) Jeng (2008) and Roza (2022).
Remarks. This species was referred to as "adamsi" in the majority of publications. The original spelling "adamsii" was used only by McDermott (1914), Ohba et al. (1996a), and Kawashima (2000). However, following Article 33.4. of the Code (ICZN 1999), the original spelling should be maintained. It should be noted that the current concept of D. adamsii may include several species.
Remarks. See more information on Haplocladon, which was once considered a subgenus of Diplocladon (Gorham 1883b) or even its synonym (e.g., Wittmer 1944), under the genus name Haplocladon below. Some authors who mentioned Diplocladon were actually probably referring to Haplocladon (for more details, see Remarks under D. hasseltii). Diplocladon currently contains two described species, one from China and one from Indonesia. It is similar to Bicladodrilus and Bicladum in having strongly bipectinate antennae (Fig. 1C) and long elytra. This generic complex is in need of revision.  [as D. hasselti [sic!]]. In addition to the aforementioned literature, this species was included in PhD theses by Jeng (2008) and Roza (2022).

Diplocladon atripenne Yiu, 2017
Remarks. Based on the available figures, adults of both sexes which were reported by Haneda (1950) from Singapore, and repeatedly mentioned in subsequent studies (e.g., Harvey 1952;Haneda 1955Haneda , 1985Lloyd 1971Lloyd , 1978Crowson 1981;Kawashima et al. 2010), are probably members of Haplocladon. We are aware of several Haplocladon specimens from Singapore (deposited in NHMUK) but no Diplocladon are known from that area.  (2008) and Roza (2022). Remarks. Dodecatoma currently contains eight described species from Afghanistan, India, Nepal, Indonesia, and the Philippines. This genus is in need of revision; taxa from Southeast Asia should be removed from Dodecatoma, and the generic assignment of the species with serrate antennae described recently by Kazantsev (2012) needs careful re-examination (the remaining species of Dodecatoma, including the type species, have pectinate antennae).
Type depository. Described based on an unknown number of specimens. Syntype, male (OUMNH).
Type locality. India: Deccan Plateau (without further details; "North India" on the label of the syntype in OUMNH).
Remarks. Wittmer (1938: 301) described the aberration of F. humeralis (ab. unicolor) from Tangkuban Perahu ["G. Tangkoeban Prahoe"] based on material from the collection of F. C. Drescher (possibly in MZB); however, this name is deemed to be infrasubspecific according to the Code (ICZN 1999, Article 45.6.2.). (Pic, 1914) (2008). Remarks. Gorham (1883b) originally described Haplocladon as a subgenus of Diplocladon but later treated it as a separate genus (Gorham 1895(Gorham , 1903. Unfortunately, he named type species of both Diplocladon and Haplocladon as "hasseltii" (Gorham 1883a, b), which probably confused some subsequent authors who treated Haplocladon as a synonym of Diplocladon (Olivier 1910;Wittmer 1944;Li and Liang 2008). Crowson (1955) and Paulus (1972) again considered Haplocladon a separate genus. Since Haplocladon differs at first sight from Diplocladon by the unipectinate antennae (versus bipectinate in Diplocladon), we prefer to keep Haplocladon at a generic level. Because Diplocladon hasseltii Gorham, 1883a and Diplocladon hasseltii Gorham, 1883b (described in subgenus Haplocladon) are primary homonyms, the latter junior name is permanently invalid (Art. 57.2 of the Code; ICZN 1999) and should be replaced by a new name (see below). Currently, Haplocladon contains two species, one from Indonesia and one from southern India. Based on the available figures, specimens reported by Haneda (1950) from Singapore and identified as Diplocladon hasseltii, which were later mentioned by other authors (e.g., Harvey 1952;Haneda 1955;Lloyd 1971;Lloyd 1978;Crowson 1981;Haneda 1985;Kawashima et al. 2010), are probably members of Haplocladon. Remarks. Gorham (1883b: 250) also reported an unnamed variety of H. hasseltii as "var. totum testaceum" (i.e., colour description but not the official name of the variety) from Ardjoeno and Batavia in Java. At least one specimen from Batavia labelled as "var." is present in MNHN. Two specimens from Ardjoeno and one specimen from Batavia deposited in RMNH bear the label "Type"; however, based on Article 72.4.1. of the Code (ICZN 1999), they should not be considered a part of the type series for Haplocladon gorhami. Gorham, 1903 Haplocladon indicum Gorham, 1903 Liu et al. (2020: 46a): luciferase, phylogeny, figures of male and female habitus, and female bioluminescence. In addition to the aforementioned literature, this genus was included in a PhD thesis by Jeng (2008).

Haplocladon indicum
Remarks. Menghuoius currently contains three described species from China, Myanmar, and Vietnam. It is similar to Rhagophthalmus in habitus, short, serrate antennae, and deeply emarginate eyes but differs in the large size and robust mandibles (Kawashima 2000). Menghuoius was implicitly considered a junior synonym of Rhagophthalmus by Li et al. (2008a) based on the similar morphology of females of both genera. However, since the morphology of highly paedomorphic, larva-like females of Rhagophthalmidae is much less informative than the morphology of adult males, we consider Menghuoius a separate genus until a detailed revision of Rhagophthalmus and related genera is carried out.  Liu et al. (2020: 47): remark. In addition to the aforementioned literature, this species was included in a PhD thesis by Jeng (2008).
Remarks. This genus currently contains a single described species from Java, Indonesia. According to Pic (1937), it is characterized by having serrate antennae with thickened median antennomeres, and relatively long elytra. The specimen identified as Mimochotyra [sic!] and used in the molecular phylogenetic analyses by  and more recent studies needs serious re-examination, as it was collected in Malaysia.
Remarks. This genus has relatively long, serrate antennae and long elytra. It contains two species distributed in the Himalayas (India, Nepal).

Pseudothilmanus alatus Pic, 1918
Pseudothilmanus alatus Pic, 1918 figure caption]. In addition to the aforementioned literature, this species was included in a PhD thesis by Roza (2022).
Remarks. Roza (2020) listed Uttar Pradesh for the distribution of this species; however, it was based on the specimen from NHMUK mentioned by Kundrata and Bocak (2011a), which was collected in western Almora, Kumaon which lies in Uttarakhand (considered to be part of Uttar Pradesh prior to 2000).

Pseudothilmanus marginatus Pic, 1918
Drilothilmanus [as a subgenus of Pseudothilmanus] marginatus Pic, 1918: 3. Pseudothilmanus marginatus: Kundrata and Bocak (2011a: 58  Remarks. Rhagophthalmus is the most speciose genus in the family. It contains 34 species from South, East, and Southeast Asia. This genus is characterized by having deeply emarginate eyes and relatively short antennae (Fig. 1E, F). Wittmer in Wittmer and Ohba (1994) synonymized Ochotyra with Rhagophthalmus, and we follow this concept until a proper revision of the genus is carried out. On the other hand, Menghuoius, which was synonymized with Rhagophthalmus by Li et al. (2008a), is considered here a separate genus (see Remarks under Menghuoius).
Type depository. Described based on an unknown number of specimens. Syntype, male (RMNH). Three additional male specimens (on one pin) from MNHN with labels different from the RMNH syntype are also labelled as "Type" but they probably represent a different species.
Type depository. Described based on an unknown number of specimens. One syntype, male (MNHN). Type locality. India (no further data). "Dekan India" written on the syntype label from MNHN.

Rhagophthalmus sulcatus Pic, 1925
Rhagophthalmus sulcatus Pic, 1925b: 72. Type depository. Described based on an unknown number of specimens. No type material was found in MNHN by RK.
Remarks. This species could be a synonym of R. sulcicollis Olivier, 1912(see Wittmer 1997 for more information).
Type depository. Described based on an unknown number of male specimens. No type material was found in MNHN by RK. Type locality. China (no further data). Distribution. China (no further data).
Remarks. Cydistus was originally placed in Drilidae (Olivier 1910;Wittmer 1944). Later, Crowson (1955) hypothesized Cydistus might be an intermediate form between Karumiidae (currently a subfamily in Dascillidae) and Phengodidae. Although Paulus (1972) erected Cydistinae within Karumiidae for Cydistus, Crowson (1972) transferred this genus into the widely delimited Phengodidae, which also included Rhagophthalmidae. Lawrence and Newton (1995) and  classified Cydistus in Phengodidae: Rhagophthalminae. Lawrence et al. (2010a, b) and Lawrence (2016) considered Cydistinae in Elateriformia incertae sedis. Finally,  were the first to include Cydistinae in a molecular phylogenetic analysis, and found them sister to the New World Phengodidae, which are only distantly related to Rhagophthalmidae. This placement was confirmed by a morphology-based analysis by Roza (2022).
Remarks. Reductodrilus was initially placed in Drilidae (Pic 1943;Wittmer 1948). After most Drilidae genera were transferred to different families (e.g., Lampyridae, Lycidae, Omethidae, and Rhagophthalmidae) by Crowson (1972), Reductodrilus remained in an uncertain position. Kundrata and Bocak (2011a) listed it in Rhagophthalmidae in their revision of Pseudothilmanus. Probable syntypes of both subspecies of R. nigroapicalis are deposited in MNHN. Here, we tentatively transfer Reductodrilus to Lampyridae: Ototretinae based on its suboval and somewhat flattened body, antennae with 11 antennomeres which clearly extend beyond the posterior pronotal margin, head partially covered by pronotum, eyes clearly separated by frons, pronotum transverse, medially elevated, with anterior angles inconspicuous, rounded, and posterior angles projected posteriad (for more details see Janisova and Bocakova 2013). A detailed revision of this genus should improve our understanding of its systematic position.

Discussion
Although Rhagophthalmidae have been known to entomologists for more than a century, their taxonomy and classification are still poorly known. The number of genera included in Rhagophthalmidae and also their placement within Elateroidea classification vary by source (e.g., McDermott 1966;Crowson 1972;Lawrence and Newton 1995;Kawashima et al. 2010;Kundrata and Bocak 2011a). In the last decade, Elateroidea systematic research has accelerated and the classification of the superfamily has experienced many taxonomic changes (e.g., Kundrata et al. 2014Bocak et al. 2018;Kusy et al. 2018bKusy et al. , 2021, including the discoveries of two new recent families Rosa et al. 2020) and one new extinct family (Li et al. 2021b). However, only six new species of Rhagophthalmidae were described in three taxonomic papers in the same period (Ho et al. 2012;Kazantsev 2012;Yiu 2017). This is especially striking when compared to the most closely related family of Rhagophthalmidae (i.e., Phengodidae), where numerous taxonomic studies were published (e.g., Constantin 2014Constantin , 2016Zaragoza-Caballero and Hernández 2014;Roza et al. 2017Roza et al. , 2018Roza andMermudes 2019, 2020;Vega-Badillo and Zaragoza-Caballero 2019;Vega-Badillo et al. 2020, including not only descriptions of several new genera and species but also phylogenetic analyses of the group (Zaragoza-Caballero and Zurita-García 2015; Quintino 2017; Roza 2022). In Rhagophthalmidae, the most important research topics include taxonomic limits, phylogenetic relationships, accurate dating of the origin of the group, the evolution of bioluminescence and paedomorphosis, systematics of all genera (including revisions of already known species as well as descriptions of new taxa), descriptions of paedomorphic females and immature stages for all genera and species, and evaluating the distribution of the group at both generic and family levels.
Phylogenetic relationships, origin, and monophyly of Rhagophthalmidae The phylogenetic placement of Rhagophthalmidae within Elateroidea has been controversial based on morphology only (Crowson 1972;Lawrence 1988;Branham and Wenzel 2001;Lawrence et al. 2011), and Rhagophthalmidae were often placed either in or close to Lampyridae or Phengodidae. Molecular phylogenetic analyses using various datasets and analytical approaches repeatedly confirmed that Rhagophthalmidae are sister to Phengodidae Kundrata and Bocak 2011b;Kundrata et al. 2014;Zhang et al. 2018;Douglas et al. 2021;Kusy et al. 2021;Cai et al. 2022). Both families share soft-bodied males with large eyes, often bipectinate antennae with 12 antennomeres, leathery elytra which are usually shortened and narrowed, larviform females, and larvae that possess bioluminescent organs and feed on millipedes (Kawashima et al. 2010;Zaragoza-Caballero and Hernández 2014;. Kusy et al. (2021) defined the "lampyroid clade", which contains Lampyridae, Phengodidae, Rhagophthalmidae, and Sinopyrophoridae. Fossil Cretophengodidae were probably also a part of that clade (Li et al. 2021b).
The date of the origin of Rhagophthalmidae is unclear, as there are no known fossils of the group. Generally, soft-bodied elateroids are rarely found as fossils, and to date, the most informative fossils are inclusions in various ambers. Cretophengodidae were described from mid-Cretaceous amber of northern Myanmar (ca. 99 Mya, Shi et al. 2012;Li et al. 2021b), and Kusy et al. (2021) reported unpublished Phengodidae from the same deposit. Kusy et al. (2021) summarized and reviewed the published molecular dating analyses of the elaterid-lampyroid clade, and showed that median estimates suggest the split of the Lampyridae, Phengodidae, and Rhagophthalmidae clade in the mid-Cretaceous. However, an earlier date is also possible (Kusy et al. 2021).
Another important issue is the monophyly of Rhagophthalmidae. The group was originally proposed only for Dioptoma, Ochotyra, and Rhagophthalmus (Olivier 1907(Olivier , 1910, and later Pic (1937) added Mimoochotyra. This concept was adopted by McDermott (1964McDermott ( , 1966. Crowson (1972) transferred some Asian genera (Cydistus, Diplocladon, Falsophrixothrix) from Drilidae to Phengodidae, and these were later added to Rhagophthalmidae together with Dodecatoma (Lawrence and Newton 1995). Cydistus was later transferred to Phengodidae . The current concept of Rhagophthalmidae consists of males which have exactly 12 antennomeres, with antennomere III being longer than antennomere II, a telescopic abdomen that is usually narrowed apically, and females which are more or less larva-like. However, the monophyly of this group as currently defined has never been rigorously tested.
Several genera were included in molecular phylogenetic analyses, including Bicladodrilus, Falsophrixothrix, Mimoochotyra, and Rhagophthalmus (incl. Ochotyra) Kundrata et al. 2014. These genera always formed a monophylum. However, it should be noted that at least the generic placements of specimens identified as Bicladodrilus sp. from China and Mimoochotyra sp. from Malaysia are dubious. As Bicladodrilus, Bicladum, and Diplocladon are similar in general appearance and possess biflabellate antennae, this generic complex is in need of revision. While there are no described Bicladodrilus species in China, a species of Diplocladon was recently described from Hong Kong (Yiu 2017). The single described species of Mimoochotyra is known from Java (Pic 1937;Wittmer 1944).
In his unpublished PhD thesis, Jeng (2008) focused on systematics and paedomorphosis (neoteny) in Lampyridae. He also included representatives of the rhagophthalmid genera Dioptoma, Diplocladon, Dodecatoma, Falsophrixothrix, Menghuoius, Monodrilus, and Rhagophthalmus (incl. Ochotyra) in his morphologybased analyses. These genera were monophyletic and sister to Phengodidae. In another unpublished PhD thesis, Roza (2022) focused on phylogenetic relationships of Phengodidae, and included Bicladodrilus, Dioptoma, Diplocladon, Dodecatoma, Falsophrixothrix, Pseudothilmanus, and Rhagophthalmus in his morphology-based analyses. These genera formed a monophylum in all analyses performed. A phylogenomic analysis including representatives (ideally type species) of all rhagophthalmid genera would be a valuable assessment of the monophyly of the group.

Bioluminescence and paedomorphosis in Rhagophthalmidae
Within Coleoptera, bioluminescence can be found almost exclusively within the so-called "elaterid-lampyroid clade", including Elateridae, Lampyridae, Phengodidae, Rhagophthalmidae, and Sinopyrophoridae, and probably the extinct Cretophengodidae (Oba et al. 2011;Fallon et al. 2018;Bi et al. 2019;Li et al. 2021b;Kusy et al. 2021;Powell et al. 2022). In Phengodidae, all known larvae and females are bioluminescent, as are males of some species (Costa and Zaragoza-Caballero 2010). Bioluminescence is hypothesized for lineages in which larvae and females are unknown (e.g., Cydistinae; . All known larvae and females of Rhagophthalmidae are bioluminescent. Both larvae and females were reported for Diplocladon (in fact, it is probably Haplocladon; see Remarks under both genera), Menghuoius, and Rhagophthalmus, whereas only females are known for Dioptoma (Green 1913;Gahan 1925;Coblentz and Hughes 1926;Ridley 1934;Haneda 1950;Raj 1957;Lloyd 1971Lloyd , 1978Wittmer and Ohba 1994;Ohba et al. 1996a;Kawashima 2000;Jeng 2008;Li and Liang 2008;Li et al. 2008a;Kawashima et al. 2010). Males of at least some genera (e.g., Dioptoma and Rhagophthalmus) also emit light (Kawashima et al. 2010). At least in some cases, however, there are doubts about the correct genus identification of larvae or females. For example, Jeng (2008) suggested that the giant larviform female from Yunnan, China, identified as Diplocladon by Li and Liang (2008) is "likely of Menghuoius giganteus or the other related species described from there" (Jeng 2008: 135). The correct identification of larviform females is, however, very important for conclusions on the evolution of morphological modifications caused by paedomorphosis (e.g., Jeng 2008; Kawashima et al. 2010). This should be possible by e.g., rearing both sexes of the same species from larvae, finding a mating couple, or by the use of DNA barcoding. Information on the life-history and biology of most genera of Rhagophthalmidae is minimal or entirely absent. Further research should be conducted to confirm the presence of bioluminescence in the remaining rhagophthalmid genera.

Generic classification and systematics of Rhagophthalmidae
It is clear from the above text that the classification and systematics of Rhagophthalmidae is in a very poor state of knowledge. Species of Bicladodrilus, Bicladum, Falsophrixothrix, Mimoochotyra, and Monodrilus have not been taxonomically treated since their descriptions, and their names have usually appeared only in catalogues, if at all. Taxonomic revisions are urgently needed for all genera currently included in Rhagophthalmidae with the exception of Pseudothilmanus, which was revised recently (Kundrata and Bocak 2011a). Although the most species-rich genus Rhagophthalmus received some taxonomic attention in the last decades (e.g., Wittmer and Ohba 1994;Wittmer 1997;Kawashima and Satô 2001;Kawashima and Sugaya 2003;Li et al. 2008a;Ho et al. 2012;Yiu 2017), a comprehensive revision is still needed.
Due to a scarcity of information on the morphology of most rhagophthalmid taxa, an identification key which would help taxonomists to recognize genera and species in collections and subsequently enhance knowledge on their diversity, variability, and distributions, is also missing. Most importantly, it is necessary to delimit generic boundaries in some problematic generic complexes. For example, Bicladodrilus, Bicladum, and Diplocladon share biflabellate antennae and relatively long elytra, and are not clearly distinguished from one other. Detailed taxonomic studies should also be conducted to revise the status of Ochotyra (currently a synonym of Rhagophthalmus) and Menghuoius (currently a separate genus but treated by some authors as a synonym of Rhagophthalmus). Some genera contain species which are probably not congeneric with their type species (e.g., some Dodecatoma spp. resemble Pseudothilmanus more than D. bicolor), and e.g., Dodecatoma testaceiceps should be removed from Rhagophthalmidae after a detailed revision. Taxonomic attention should be given not only to currently described taxa, but also to numerous undescribed Rhagophthalmidae mainly from Southeast Asia, which are housed in various institutional and personal collections (RK pers. obs.).
Taxonomic revisions are usually hampered by missing, lost, or otherwise unavailable type specimens, especially in long-neglected groups, such as Rhagophthalmidae. However, the vast majority of name-bearing rhagophthalmid type specimens are available in European and Asian museum collections. To date, we have been unable to locate name-bearing type specimens of only five species described by either Pic, Fairmaire, or Olivier, four of which belong to Rhagophthalmus. Name-bearing type specimens of species in 10 smaller genera are each deposited in one to three museum collections only; however, those of Dodecatoma and Rhagophthalmus are in seven and 12 institutions, respectively.

Distribution of Rhagophthalmidae
Rhagophthalmidae are distributed in the Oriental realm and the Palaearctic bioregion of East Asia, in the area from Afghanistan and Pakistan, through the Himalayas, Indian Peninsula, Sri Lanka, China, and mainland Southeast Asia, to Sumatra, Java, Bali, Borneo, and the Philippines. The center of genus-level diversity of Rhagophthalmidae lies in Southeast Asia. Nine out of 12 genera have at least one species distributed in Southeast Asia, with five genera (i.e., Bicladodrilus, Bicladum, Falsophrixothrix, Mimoochotyra, and Monodrilus) being endemic to the region. However, this only accounts for approximately one third of described species. The genera Dodecatoma and Pseudothilmanus are known only from the Himalayas and surrounding regions (one species and one subspecies of Dodecatoma from Southeast Asia should be removed from that genus), and Dioptoma is endemic to the Indian Peninsula and Sri Lanka. Regarding the most species-rich genus Rhagophthalmus, only seven out of 34 species are known from Southeast Asia, including only a single species from the Greater Sunda Islands. Another seven species are known from the Indian Peninsula and Sri Lanka, and the remaining majority of species are distributed in mainland China and among the islands of East Asia.
Interestingly, in the eastern part of their distribution, Rhagophthalmidae have remained within the boundaries of the Sunda Shelf and the Philippines, i.e, west of the originally proposed Wallace Line, which was demarcated to separate Indo-Malayan (Oriental) and Austro-Malayan (Australasian) realms (Wallace 1863;Voris 2000;Lohman et al. 2011). The Sunda Shelf is a southward expansion of the continental shelf of Southeast Asia that was intermittently exposed by lowered sea levels during the Pleistocene (Hall 1998;Voris 2000;Lomolino et al. 2017). The Wallace line separates Bali and Borneo on the west from Lombok and Sulawesi on the east. It is a strong dispersal barrier to many terrestrial animals because of deep oceanic trenches (Lomolino et al. 2017). Rhagophthalmidae have a limited dispersal propensity due to their highly modified larviform females and, therefore, it is not surprising that they remained within the boundaries of the continental shelf of Southeast Asia, with a single described species from the Philippines. Additionally, it should be noted that there are no Rhagophthalmidae from east of the Wallace Line among the extensive material of non-type specimens (including numerous new species) that reside in major European museums and several personal collections, which the first author examined for a planned generic revision of the group. A single, unreported rhagophthalmid species from Bali is the closest that the family has been observed to the Wallace Line. A taxonomic revision of Rhagophthalmidae will further improve our knowledge of the distributions of individual genera and their species, some of which are currently known only from a single specimen.

Conclusions
Here we provide the first comprehensive catalogue of the currently defined Rhagophthalmidae. The only catalogues of the group were those of Olivier (1910) and McDermott (1966; Rhagophthalminae as a subfamily of Lampyridae) but they contained only three genera and nine species, and four genera and 21 species, respectively. Here, we recognize 12 genera and 66 species. However, all genera but Pseudothilmanus urgently need taxonomic revisions, and numerous new species await formal descriptions. The phylogenetic position of Rhagophthalmidae as a sister group to Phengodidae is now generally accepted; however, interrelationships within the group and generic classification remain poorly known. Although morphology-based analyses in two PhD studies that were focused on related families (Jeng 2008;Roza 2022) confirm the monophyly of currently circumscribed Rhagophthalmidae, molecular analysis including representatives of all genera would be desirable. Additionally, little information is known of the biology of the group. Although various studies have been published on the ontogeny, biology, and behaviour of the most common genus Rhagophthalmus, there is virtually nothing known about the majority of other genera. Because known females in Rhagophthalmidae are highly morphologically modified and remain larviform as adults, they are interesting subjects for researching the evolution of paedomorphosis in Elateroidea. However, only a few have been studied in detail (Kawashima et al. 2010). Additionally, all known larvae and females (and some males) are bioluminescent, and therefore are an important source of information for research on the evolution of bioluminescence in beetles. However, this phenomenon is also understudied in Rhagophthalmidae, as larvae and females are unknown for most genera. Discoveries, field observations, morphological studies, and correct genus and species identifications of larvae and larviform females of Rhagophthalmidae are therefore crucial not only for our improved knowledge of the diversity, systematics, and morphology of the group, but also for a better understanding of the evolution of paedomorphosis and bioluminescence in Elateroidea and beetles in general.
of Science, UP Olomouc (IGA_PrF_2022_024; to RK, JH, and GP). RK received support from the SYNTHESYS+ project which is financed by European Community Research Infrastructure Action under the H2020 Integrating Activities Programme, Project number 823827 (projects ES-TAF TA1-2536 and GB-TAF-8656 for stays in MNCN, Madrid and NHMUK, London, respectively).