World Chloropidae Online Introduction

Table of contents

  1. Treatise
    1. Larval substrate of Chloropidae
    2. Minimalist morphological definition for world Chloropidae
  2. Digitization of the Chloropidae File Cards
  3. Structure of the Website
    1. Hit List
    2. Detail Page
  4. Operation of the Website
    1. Finding Scientific Names
    2. Sorting the Hit List
  5. Right of use

1. Treatise

1.1. Larval substrate of Chloropidae

Among 1,141 studied acalyptrate flies from Eocene Baltic amber belonging into the "Acalyptratae" (see next chapter), 161 undescribed species were detected in addition to the 56 described ones. With 43 specimens, Protoscinella electrica was the most frequent species of Acalyptratae (21721:177). Only three minute morphological details distinguish this 2.5mm long fossil species from extant Tricimba morphology. We can assume, that the biology of this species in its subtropical forest 48-34 million years ago was similar to our extant Holarctic and ubiquistic Tricimba species (globally 181 valid spp.). A variety of larval Tricimba substrates were published, fungi, rotting plant matter, berries, and egg masses in spider cocoons. Saprophagy and bacteriophagy is regarded as the basic nutrition of chloropids, and this type of food ingestion is always based on the possession of a horizontal filter apparatus in the mouth chamber of the larva (see below). Predaceous and zoophagous larvae are known preying on thrips and root aphids or to consume life eggs of Arachnida (spiders and whip spiders), Mantodea (mantids), Orthopteroidea (grasshoppers and katydids), or they are parasites in the skin of Australian frogs; larvae of few species consume manure of chicken or other animal faeces and some inquiline species have been reared from twig galls induced by bacteria (personal observation) or cynipids. True phytophagy with host plant specificy is rare (e.g. Dicraeus spp., Lipara lucens) and assessed as apomorphous clades in the phylogeny of the family. Most agricultural pest species on cereals and other monocots are prejudged as being phytophagous insects. But bacteria and protozoans play an important role in their diet. Those are transferred via the egg laying female together with the eggs, which become already infected in the mother's genital tract. The larval mouth hooks damage the young initial cells of the vegetation cone (at infection time being protected inside the leaf sheaths), thus propagating the bacteria and protozoans, which destroy the middle lamellae of the young cells by releasing pectinase. Finally, the larva minimises the volume of their dorsal mouth chamber. By this action, the mixture of cell compartiments is separated from its water content and ingested from the dorsal mouth chamber into the connected oesophagus. The moisture, which before had been pressed downwards through the microfilter (mesh width less than 1μm) into the ventral mouth chamber, is salivated back onto the vegetation cone, thus remaining damp and becoming rotting, which means production of more microorganisms. Specific plant and microorganism DNA may be responsible for host plant specalisation of many chloropid species. Specific research study is still required to understand the reasons for the host specificy of phytosaprophagous and "phytophagous" chloropids, e.g. the species of the harmful Oscinella frit group or the goat fly Chlorops pumilionis, both attacking cereals. A tremendous literature on these two agricultural pests is included in this database beginning with the earliest observation of Marcus Terentius VARRO 35 years before Christ. From VARRO’s book "On agriculture", Carolus LINNAEUS in his "Systema Naturae" (1758) dedicated the name of the "frit fly" (his Musca frit) inhabiting each Palaearctic cereal crop.

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1.2. Minimalist morphological definition for world Chloropidae

A multitude of works for the identification of families of Diptera are included in the database "World Bibliography of Agromyzidae and Chloropidae Online", and more than 100 references for Chloropidae are equipped with the keyword "family keys". The ten most actual and complete ones since 1973 can be entered using the BIBLIO numbers 25669, 21807, 25019, 21343, 22060, 17626, 8682, 10169, 15961, 10202. The sequence starts with the fantastic and most recent one available free of charge at https://www.nhm.ac.uk/our-science/our-work/biodiversity/manual-afrotropical-diptera.html. In German language and focused on Central Europe, the references 20899, 22514 and 28111 may be added. The following German title could no longer be included in this database:

Chloropidae (Frit flies, Cereal flies, Grass flies, Eye gnats) belong into the so-called Acalyptratae Macquart, 1835 (often misspelled as Acalyptrata). This group of "true" flies include more than 50 families, most of which can be grouped into superfamilies. Chloropidae are a phylogenetic sister of Milichiidae and are included in the superfamily Carnoidea. But molecular data did not yet resolve the correct superfamily placement (27003:2-8). Acalyptates normally (exception for example Platystomatidae, Psilidae) lack a dorsolateral longitudinal V-shaped seam in their 2nd antennal segment, the 'pedicel', they do not possess a large thoracic squama (landing flap) below the wing base, their dorsal thoracic transverse suture is widely interrupted in the anterior centre of the scutum (=mesonotum), their single outer postalar seta is not inserting on a small callus being surrounded by a weak groove, and tibiae miss long strong bristles or they possess only one or few short setae. All those features apply for world Chloropidae, too.

Shared with many other acalyptrates and the characteristics used in all identification keys are the following feutures: Size 0.8-9.5mm; wing always with only one costal break close to and basally of the junction of vein R1; with the costa (this break is sometimes difficult to ascertain, e.g. in certain Apotropina spp.); the subcosta is fading away distally or only vestigial and very close to or melted with vein R1; vein R4+5 and vein M1 are never strongly convergent at distal end (rare exception is a slight convergence, e.g. in Pseudogaurax species); all head bristles of the ground pattern of acalyptrates are also found in certain chloropids, but their pecularity is highly variable (procurved, recurved, convergent, divergent, parallel, long, short, strong, thickened, weak, dark, light, absent); the fronto-orbital setae between eye edge and frons are not bent inwards or outwards and are arranged in row; vibrissae are mostly present or rerely absent; interfrontal hairs may be abent or present, sometimes developed as few pairs of bristles (Apotropina); ocelli are always present; the ocellar triangle - used in many keys as being characteristicly large - in many genera is absent or covered by dense grey pubescence; the thoracic chaetotaxy is as variable but always at least one dorsocentral is present; acrostichals on the scutum (=mesonotum) are arranged in rows or evenly distributed, or absent; tibiae invariably without a dorsal preapical seta; tibial organ on hind-tibia partly present; wing without any remnants of the disappeared anal cell (=basal cubital cell); abdomen rarely with united and enlarged tergites, postabdomen with asymmetric or symmetric structures; halteres normally present, but absent (Alombus spp.) or vestigial, too; wings rarely vestigial or absent; antenna present (female of Kurumemyia ongamea without arista is a singular exception (8122:144). All these enumerated features are shared with certain other families of Acalyptratae and thus, they cannot be used to define without doubt the Chloropidae.

By the beginner, the chloropid habitus can easily be mixed up with certain Milichiidae, Chyromyidae, Canacidae: subfamily Tethininae) and certain Ephydridae. But the following synapomorphies let chloropids identify without doubt, including amber fossils:

Detected by Malloch (5606:396; 4026:495,499), above the fore coxa, the propleuron (=proepisternum of the prothorax) has a sharp carina extended until the lower edge of the humeral callus (=postpronotum), unique within Acalyptratae. In tiny chloropids it is difficult to detect because of missing strong magnification of the stereomicroscope and poor artificial illumination; in such cases, the head of the fly must be removed in order to have a better oblique anterior view. The polished carina is never covered with microtrichia or dust.

By John R. Malloch only in the year 1934 and differently formulated 1948, the most important detection of two singular apomorphies of Chloropidae were published. These historical two "dry" sentences from 1934 should be cited here: "Prosternal plate with a sharp anterior margin, in front of which the surface is abruptly precipitous, the propleura similarly margined at anterior edge of its lateral exposure. … In addition … the great majority of the species possess a peculiar rather slight flexure of the fifth wing-vein near middle of the discal cell, …"

The mentioned second apomorphy, singular in Chloropidae (but not distinct in all genera) is a peculiar kink (flexure) in the basal part of wing vein M3+4 just in that position, where the anal cell should have been touched this vein in pre-Eocene times. All my studied of M.v.T. amber inclusions of Protoscinella electrica and P. sp. n. possess a fragmentary not fully closed anal cell and remnants of the outer end of this cell, named CuA, anterior branch of cubital cell (25700:2). The meeting point CuA with M3+4 in Baltic amber fossils and also in studied undescribed Dominican amber Tricimba species exactly agrees with the vein flexure in extant Chloropidae. In all other extant acalyptrates of different families without an anal cell and without posterior cross-vein I never detected such a kink/flexure in M3+4. In combination with these two features, the above mentioned pro- or re-curved fronto-orbitals (if present) may additionally confirm an identification. One or two scapular bristles (scp) in several Siphonellopsinae and some Oscinellinae (Microcercis) should be mentioned here. One of both (on each side) is wrongly figured only for Lasiopleura longepilosa by Andersson (7299:25). These macrochaetae may belong to the ground pattern of Chloropidae but they seem to have been lost during evolution in the advanced subfamilies of chloropids. The same applies for one present intraalar seta (ia) missing in the same mentioned figure and also for the depicted supraalar (sa). Information on these three or four bristles is very rare in the literature. The seldomly mentioned supra-alar seta was discussed by M.v.T. (21721:178). It always should be searched in species of scarcely collected genera.

The 13 most recent English language keys for genera identification are found in 27077, 19704, 22982, 22122, 20138, 15631, 9294, 2791, 8983, 8122, 13570, 8829 7299. For latest keys to genera level, in Bulgarian, Chinese, Czech, German, French, Japanese, Portuguese, and Russian, the user must combine the keywords "keys to genera" plus "Chloropidae". Not any world key exists for all valid taxa of the genus group.

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2. Digitization of the Chloropidae File Cards

The index of the world Chloropidae includes about 5,243 scientific names with 7,610 file cards with information on names and their source. The collection of literature was started in 1966 and continued until the end of 2022. Some few sources and new taxa published between January 1 and May 31 were included, too. An EXCEL list with the information in the header of each card has been maintained since the use of a computer in 1998. In addition to the scientific name are following: author(s), year and - if necessary - round brackets around both, finally after a dot genus and in round brackets subgenus. If a name actually is invalid (being a junior synonym, nomen dubium, nomen oblitum, nomen nudum, misspelling or another error) the complete name is set in square brackets.

All found published phylogenetical clade names (being outside the Rules of the ICZN) are collected for the first time and are included in the list, too. They are underlined in red colour, are combined with the word "group" or [German] "Gruppe" and are positioned in front of the valid or invalid species or genus name.

In addition, there are cards with further information that can be found via "further information". With the exception of "frit", they are limited to genus names. These lines appear alphabetically after the respective genus or species. An example is the following sequence: frit Linnaeus 1758 = group (clade name) with 2 index cards about the frit group, frit Linnaeus 1758 = species group name with 135 index cards about Oscinella frit and frit Linnaeus 1758 = information with 2 index cards about synonyms.

Thus, their positions of "group (clade name)" and "further information" are the only exceptions of the strict alphabetic order of all names. The alphabetic sequence was not automaticly generated by EXCEL but thoroughly by eye: All words and year-numbers in a name have been used as if they are combined to one single long word. For this ordering only brackets have been neglected. Family group names ending with …idae are only added to a header name if that one actually belongs into another family of Diptera or to a homonymous other animal. Only in the header of the first of several cards for a name all further genera and subgenera in which the species ever had been treated or listed are noted in square brackets. Multiple cards (up to 135 for Oscinella frit) exist for many names. They are numbered consecutively by an encircled number at the top right. Just below this number partly a date is added (day, month, year). It indicates the day when this further card was established with its first entry.

Nevertheless, if it is doubtless that a species was misidentified in a used source, the reference is listed on the card with the erroneously used name. There are some few exceptions for such cases when the correct actual valid name could be found out for the misidentification. In such exceptions, the citation has also an entry on the card for the correct name but this is set in brackets. Thaumatomyia notata is such an example, recorded by Curtis (1860) and Fallada (1910) as Chlorops taeniopus and by Jenyns (1832), Waga (1848), and Laboulbène (1875) as Chlorops laeta.

Below the header of a card further information follows: All found publications relating to the name, abbreviated as Author(s), year, exclusively all exact pages in the article or book, partly notes on the contents or taxonomy and in many cases even the BIBLIO number of the database at the right end of a line. Red underlined notes in certain references apply to the original description or first publication of an actual taxonomical status in the year 2022. Lower case letters behind the year were not used for multiple publications of an author within one year. In most such cases the given pages exclude errors in selecting the belonging article or book in "World Bibliography of Agromyzidae and Chloropidae Online". In early written entries for some few authors [for example Hering; Spencer] such lower case letters were used. As not repeated in "BIBLIO" they should be neglected.

The header of the file cards corresponds to the information in the EXCEL list and the data set in the database. All names, valid or not, species group, genus group, family group and nomenclaturally not protected clade names are presented in one single list. In order to publish the world index of Chloropidae on the Internet, the file cards and the basic EXCEL list were thoroughly revised which required several years labour. The data from the EXCEL list were transferred to database tables. They were initially used for indexing all file card images and now used for accessing the images by name, author, year, etc. All file cards were scanned exactly according to their order in the file card boxes. If the backs are also used, the images follow the respective front. Processing using OCR (optical character recognition) was not planned.

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3. Structure of the Website

Via the menu ☰ at the top edge of the screen you can reach the settings, this introduction, M. von Tschirnhaus' bibliography and "World Agromyzidae Online" as well as further links to   Diptera. Under the menu item Settings you can change the language of the controls and some data in the hit list, for example in the columns "Rank" or "Valid". Choose German or English. Enter the number of rows that you want the hit list to display and then click "save". A cookie on your device will now contain this information for future visits to the website. If you choose "do not save", no cookie will be saved and the program will use English and 10 lines.

Below the menu the scientific names (=rows of the table, =data records) are displayed in the form of a table. At startup, this hit list contains all names in undefined order. Only as many rows are displayed as defined in Settings. However, only the 8 columns that can be searched are visible. All further information can be found under "World Chloropidae Online Details". To do this, click on the data sheet icon to the left of each scientific name. Finally, the number in the blue circle signals the number of file cards associated with the name.

The pagination buttons are located below the hit list. Depending on the position in the database, you can scroll back with the left and forward with the right buttons. The page number and the count of the visible data records are given between the buttons.

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3.1. Hit List

Searching for the name you want and sorting the lines of the hit list is done using the controls in the three-line table header. A selection of sorting operators is hidden below the column title , a selection of search operators below the second header line , and the search term can be entered in the third line . Active operators and search words are displayed in blue font on a light background. The query in the example above can be read from top to bottom as: Search for lines from Chloropidae for which: scientific name starts with abb .

The left column of the table, called "Action", shows two buttons in the table header. With the button submit, the previously entered query is sent to the server. The button reset triggers a defined initial state, theat is all scientific names are included in the list, sorted alphabetically and the first lines are displayed.

For each line in the table body, the action column shows the data sheet icon with the number of associated file cards. Clicking on it will take you to the details page.

The last line of the hit list contains the button for downloading the selected data. Depending on the settings in the web browser, they are displayed immediately or stored in the download directory.

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3.2. Detail Page

The file cards belonging to the scientific name are displayed on the left. If there is more than one card, the pagination buttons can be used to scroll through the deck of cards.

Below this (usually on the last file card) there are annotations that were not listed on the file cards.

On the right you will find further data, such as original citation with page number, comments, etc.

"Find references by" (bottom right) creates a link to "World Bibliography of Agromyzidae and Chloropidae Online". From the citations on the card, the first author and the year can be entered here, separated by space. Often the number from the BIBLIO database is also available. It can be used alternatively. After pressing the enter key or clicking on the symbol of the magnifying glass, the citation is retrieved from the associated "World Bibliography of Agromyzidae and Chloropidae Online" and displayed.

Finally, you can return to back the hit list with the button back to hit listat the bottom right. Please do not use the "back" button in your web browser!

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4. Operation of the Website

4.1. Finding Scientific Names

At the beginning or after clicking on reset there all scientific names are included in the hit list. To search the records based on values in the columns, the search method and the value can be typed in rows 2 and 3 of the table header.

The search method is initially set to the most commonly one used. Click on the word to change it. In the input list that now appears, select an operator, for example "starts with".

To enter a search term, click on the input field, for example below Author, and enter the name you're looking for. Then click submit. All columns selected for searching, the search operators and the search words entered are displayed in blue font on a light background.

The table below explains how to search in the various columns.

Column Method Explanation
Name starts with Finds scientific names beginning with the entered search term.
is equal to Finds scientific names equal to the entered search term.
contains Finds scientific names containing the entered search term.
Author is equal to The search for authors is facilitated by a list of the different spellings of personal names (see Authors in the menu bar). This operator first searches for the name entered in the list of persons. Then all associated spellings are determined and finally searched for in the author team. For example, a search with Marschall or de Marschall always leads to the desired result.
starts with The operator gives the best result when the end of a name is uncertain. The truncation character "%" does not have to be entered at the end of a word.
contains The operator gives the best result when the spelling of a name is uncertain. The truncation character "%" does not have to be entered at the beginning or at the end of the word.
Year is before Finds the scientific names published before the entered year.
is equal Finds the scientific names published in the entered year. With Year is equal [to] 0 you will find data records for which no year could be determined. For some scientific names, a year is meaningless, the column is empty.
is after Finds the scientific names published after the entered year.
Rank / Valid is equal to The search words are given in the associated selection list. To open this list, click on the caret pointing down in the input field. "Valid" is to be understood in the Chloropidae system.
Genus The search using genus names works in the same way as column "Scientific name".
Region contains The search is done with the so-called Boolean full text search. The operators + (plus) and - (minus) indicate that a word must be present or must not be present in order for there to be a match. Several words separated by ; (semicolon) can be entered in the input field below the title of a column. Truncation with % (percent) is possible at the end of words. Finally "" (double quotation marks) are used to enclose a fixed term that can consist of several words.
Zoogeographical regions are stored with "Afrotropic", "Australasian", "Nearctic", "Neotropic", "Oriental" and "Palaearctic". The region mentioned in the original description is marked with "²".
For example, entering Palaearctic² (without blank) will find all names that were first described for this region. In contrast, entering Pal% will give you all names for which the Palaearctis region has been mentioned in the literature (both "Palaearctic" and "Palaearctic²"). For some names, several regions have been published. To exclude all others except Palaearctic, enter +Pal%; -Afr%; -Aus%; -Nea%; -Neo%; -Ori% (+ and - and words separated by ;).
More info contains The column "More info" combines information from the EXCEL table from the columns "Original genus", "Other genera", "Other citations", "Valid oldest name", and "State" for searching. In the detailed view, these data are assigned to the original columns of the EXCEL table. The Boolean full text search is carried out as described under "Region".
Original genus Contains the original genus name.
Other genera Contains further genus names.
Other citations Contains an abbreviation and the corresponding BIBLIO number together with the page number. The most important abbreviations are: coll. = name in a collection, comb. = new combination, litt. = name in the literature, nom. = new name, stat. = revised state, and syn. = synonym. Other remarks are self-explanatory. The named BIBLIO number can be entered netx to "Find reference by" and the citation immediately displayed.
Valid oldest name Contains the valid oldest name.
For example, if you are looking for all synonyms of "Polyodaspis sulcicollis (Meigen, 1838)" enter sulcicollis below "More info". You will get 9 names: amicalis Becker, 1912; anglicus Collin, 1946; dasyprocta Loew, 1858; ...; pokornyi Becker, 1912.
State Contains the original classification of the name, partly processed in the columns "Rank" and "Valid": error in the widest sense, fossil, family transfer, homonymous genus in zoology, invalid family group name, invalid genus group name, nomen dubium, nomen nudum, preoccupied, valid subgenus, valid subspecies, suppressed by ICZN, synonym incl. variety, unjustified emendation, unavailable name, valid family group name, valid genus & subgenus, valid species, valid subgenus combination, genus clade, valid species, species clade
For example, if you are looking for names of fossil species, enter fossil below "More info".
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4.2. Sorting the Hit List

After clicking reset, the lines in the list of hits sorted by scientific name. The current sorting can be recognized by the blue font on a light background and the arrow in front of the column title in the table header. In addition, a small superscript number indicates the order in which the columns were sorted.

The column titles are used to change the order. To do this, click on it, for example on Author. In the input list that now appears, select ↓descending (Z to A), unsorted or ↑ascending (A to Z) and click on submit.

In general, the scientific names are sorted alphabetically in ascending order. If there are several lines with the same name, groups come first and additional information last.

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5. Right of use

This online database is open access CC BY-SA 4.0.

You may:

You must:

Please cite the database as follows: von Tschirnhaus, M. & Groll, E. 2024: World Chloropidae Online. - https://sdei.senckenberg.de/tschirnhaus-chloropidae

Vignette: Elachiptera diastema, Photograph Raimo Neergaard

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