Six New Species of Labeotropheus (Cichliformes: Cichlidae) from the Malaŵian Shore of Lake Malaŵi, Africa

Labeotropheus is a small genus of rock-dwelling haplochromine cichlid fishes endemic to Lake Malaŵi in the Great East African Rift Valley. As currently recognized, Labeotropheus contains five species: L. artatorostris, L. chlorosiglos, L. fuelleborni, L. simoneae, and L. trewavasae. Despite increased recent attention from taxonomists, there are still several undescribed species within this genus. Here, based upon morphological and meristic data, as well as differences in male nuptial color pattern, we describe six new species. Additionally, we update the type locality of L. simoneae. The descriptions of these new species are in line with current recommendations to better define and delimit the taxonomy of cichlids from Lake Malaŵi, which will hopefully lead to increased efforts to conserve these fishes.

L AKE Malaŵi, the southernmost lake of the Great East African Rift Valley, is home to the most diverse radiation of vertebrate life in the world, hosting an estimated 1,000 or more species of endemic cichlid fishes (Sayer et al., 2019). Perhaps not surprisingly, this lake and these remarkable fishes have been favorite study subjects for those seeking to understand the causes of this unparalleled burst of evolution, as well as those who would document and describe the diversity of these fishes (Weyl et al., 2010). What is surprising is that, after almost a century of taxonomic study, new species continue to be described. In the three years preceding this study, 14 species have been described in seven published papers (Dierickx et al., 2018;Oliver, 2018;Dierickx and Snoeks, 2020;Stauffer et al., 2020;Stauffer and Konings, 2021), and the consensus among experts is that many more species of cichlid from Lake Malaŵi await description (Kanyerere et al., 2019).
The most diverse assemblage of cichlids is restricted to the shallow nearshore areas of Lake Malaŵi (Ribbink et al., 1983a;Kanyerere et al., 2019). The cichlid fauna of this habitat is dominated by the rock-frequenting haplochromines known by the Chitonga name 'mbuna.' The mbuna consist of 13 genera of brightly colored, highly stenotopic fishes, notable for the extensive genetic, morphological, and behavioral divergence among allopatric populations (Ribbink et al., 1983a;Oliver and Arnegard, 2010;Pauers and McMillan, 2015;Conith et al., 2020). While some of these genera have received extensive attention from ichthyologists, with numerous species having been added since Ribbink et al.'s (1983a) survey of these fishes, others remain in need of taxonomic attention (Pauers, 2010).
The genus Labeotropheus is one genus of the mbuna common to the rocky nearshore areas of Lake Malaŵi, and has, until recently, been overlooked by taxonomists (Pauers, 2010). It is distinguished from the other mbuna due to a steeply sloping head; broad, fleshy snout; wide jaws with retrognathous lower jaw; and an inferior and subterminal mouth (Oliver and Arnegard, 2010). First described by Ahl in 1927, Labeotropheus had long been considered to contain only two species, L. fuelleborni and L. trewavasae, despite extensive evidence suggesting the existence of numerous species within this genus (Ribbink et al., 1983a(Ribbink et al., , 1983bPauers, 2010). While recent efforts have added three additional species (L. chlorosiglos and L. simoneae, Pauers, 2016;L. artatorostris, Pauers, 2017), the presence of other allopatric and uniquely colored populations of Labeotropheus suggests the existence of yet more species of this genus.
Within Labeotropheus, a useful first criterion to employ when identifying and describing species is the ratio of body depth to body length (Fryer, 1956;Pauers, 2016). Quantifying this ratio is the first step in distinguishing robust species from slender species (Pauers and McMillan, 2015), especially if they are sympatric with one another (sensu Stauffer and McKaye, 2001). Typically, the robust Labeotropheus (e.g., L. fuelleborni, L. artatorostris) have a ratio of body depth to standard length that is greater than or equal to 35%, while that of slender species (e.g., L. trewavasae, L. simoneae) is less than or equal to 30%; additionally, there are species with intermediate body depth-standard length ratios (e.g., L. chlorosiglos; Pauers, 2016). Once a putative new species has been assigned to the robust, intermediate, or slender morphotype, other criteria, especially male nuptial coloration and craniofacial features (i.e., snout length, snout pad length, rostral length, length of the upper and lower jaws, etc.; Pauers, 2016) become useful for diagnosing new species.
Here, based upon specimens collected during the course of two expeditions conducted with the express purpose of documenting the distribution and diversity of Labeotropheus, we present the descriptions of six new species.

MATERIALS AND METHODS
Study sites.-We conducted two expeditions in Lake Malaŵi, one from 29 July to 3 August 2018, and the other from 11 to 20 January 2020. During the 2018 expedition, we obtained specimens from seven locations surrounding the Luromo Peninsula along the northwestern shore of the lake. In 2020, For the 2020 expedition, permission to conduct research on Lake Malaŵi was granted by the National Commission for Science and Technology of Malaŵi on 14 January 2020 (reference no. NCST/RTT/1/20). Permission to collect specimens from the waters of Lake Malaŵi National Park was issued on 14 January 2020; there is no permit or reference number issued on this document. Permission to export specimens from Lake Malaŵi to the United States was granted by the Malaŵi Department of Fisheries on 19 January 2020 (reference no. DF/019/200). The United States Fish and Wildlife Service granted permission to import the specimens to the U.S. on 12 December 2019 (confirmation no. 2019CH2529841).
The research activities involving live vertebrate animals that occurred during both of these expeditions were approved by the Institutional Animal Care and Use Com- Specimens.-All specimens were captured by divers who chased the fishes into monofilament gillnets. Upon capture, the fishes were photographed while alive before being euthanized with an overdose of MS-222; a dosage of approximately 250 mg/L was used to euthanize the fish. Once euthanized, the right pelvic fin was removed with scissors and placed into 95% ethanol (EtOH) for preservation and possible future genetic analyses; the remaining wholebody specimen was given an identification number and fixed in 10% buffered formalin for 48-72 hours. After fixation, the fishes were prepared for transport to the Milwaukee Public Museum by wrapping them in cheesecloth saturated with 70% EtOH; these cheesecloth bundles were then placed in three layers of plastic bagging and absorbent pads. Upon reaching the museum, the fishes were processed through a dehydration series, spending 24 to 72 hours in 10%, 35%, and 50% EtOH before being permanently stored in 70% EtOH. All institutional abbreviations follow Sabaj (2020).
Descriptions of external morphology follow Barel et al. (1977). External counts and measurements follow Barel et al. (1977), Stauffer et al. (1997), and Pauers (2016). Standard length (SL) is used throughout. Except for the counts of gill rakers, all counts and measurements were made on the left side of the fish. We also note that, contrary to Ahl's (1927) description, all the oral teeth in Labeotropheus are tricuspid, and most of the scales are ctenoid, except in the belly and anterior abdomen, where they are cycloid.
All measurements were taken to the nearest hundredth mm using digital calipers, and then rounded to the nearest one-tenth mm. Measurements taken on the trunk were standardized by SL, while those on the head were standardized by head length (HL). The morphometric and meristic data for Labeotropheus fuelleborni and L. trewavasae, the exemplar species for the robust and slender Labeotropheus, respectively, were measured by the lead author and are included for comparison in Table 2. The morphometric and meristic data from the three more recently described Labeotropheus, L. chlorosiglos, L. simoneae, and L. artatorostris, were measured by the lead author and can be found in Pauers (2016; L. chlorosiglos and L. simoneae) and Pauers (2017; L. artatorostris).
In order to diagnose putative new species of Labeotropheus, we followed Pauers (2016). Briefly, by first using the Evolutionary Species Concept (Simpson, 1961;Wiley, 1978) as a non-operational guiding principle (Mayden, 1999), the application of operational criteria were then used to distinguish one species from another.
Analyses.-Since many of the morphometric and meristic characteristics overlapped among species, we used canonical discriminant function analyses to assist the diagnoses of these species. We performed separate analyses on the Log 10transformed morphometric data and non-transformed meristic data. Comparisons among species were then illustrated by plotting pairs of morphometric and meristic canonical functions. The analyses were performed and function plots made in Systat 10.0.  -13.8926036, 34.6221075, Michael J. Pauers, Titus B. Phiri, and Sanudi Likupe, 16 January 2020;SAIAB 211373, 2 females, 79.4 and 85.1 mm SL, Malaŵi, Lake Malaŵi, Nankoma Island, -13.8840189, 34.6118803, Michael J. Pauers, Titus B. Phiri, and Sanudi Likupe, 16 January 2020.
Diagnosis.-Labeotropheus alticodia differs from the slenderbodied Labeotropheus, L. trewavasae, L. simoneae, L. chirangali, new species, and L. rubidorsalis, new species, as well as L. chlorosiglos, due to its greater body depth (37.4-40.6% SL vs. 26.3-33.4% SL in L. trewavasae; 26.9-30.8% SL in L. simoneae; 26.6-33.2% SL in L. chirangali, new species; 31.6-36.1% SL in L. rubidorsalis, new species; 31.9-34.7% SL in L. chlorosiglos). It also differs from the slender Labeotropheus due to a greater distance between the insertion of the dorsal fin and the insertion of the anal fin new species;new species). Labeotropheus alticodia differs from all other robust-bodied Labeotropheus, except L. fuelleborni, by the nuptial coloration of the males. Male L. alticodia have a pale, powder-blue body, and the dorsal and caudal fins are whitish blue with yellow trailing edges, while the anal fin is a pale yellow orange; additionally, the pelvic fins are a pale yellow orange with white leading edges. The morphometric and meristic values largely overlap with the other robust Labeotropheus, with the following exceptions: L. alticodia  -13.730081, 34.641074 -13.730788, 34.640388 -13.729377, 34.640478 -13.730081, 34.641074 2020Maleri Island -13.8840189, 34.6118803 -13.9089591, 34.6260792 -13.8926036, 34.6221075 2020  Description.-Morphometric and meristic data summarized in Table 3. Body compressiform; ovoid to almost rectangular in shape. Body deep (37.4-40.6% SL) and consistently deep throughout its length. Anterior body wide at pectoral fin and opercular tab. Scales on belly and anterior abdomen cycloid and tightly crowded. Flank scales ctenoid; exposed portion of scale fan-shaped and approximately hexagonal. Anterior lateral line overlapping posterior lateral line by 0-4 scales. Dorsal fin relatively short for Labeotropheus (55.8-60.2% SL) with 16-17 spines and 8-9 rays. First dorsal spine opposite opercular tab. Dorsal rays 3, 4, 5 long, reaching to hypural plate and beyond. Anal fin angular and kite-shaped; anal-fin rays 3 and 4 long, reaching past caudal peduncle to caudal fin. Anal-fin origin opposite dorsal-fin spine 14 or 15; anal-fin insertion anterior to dorsal-fin insertion. Caudal fin subtruncate. Pectoral fin rounded. Pelvic fin long, minimally reaching origin of anal fin and longer in most specimens; males with filamentous pelvic rays, females nonfilamentous. Attachment of pelvic fin opposite dorsal-fin spine 5 or 6.
Head of typical length for Labeotropheus (31.8-33.4% SL) but deep with strongly curved profile and slightly developed snout. Snout long and wide with snout pad of typical length for Labeotropheus (11.6-14.8% HL). Cheek with 3 scale rows. Infraorbital pores 9, with 23-38 neuromasts among them. Oral jaws short and wide. Oral teeth tricuspid and closely set on both upper and lower jaws; 7-10 tricuspid teeth on lateral portion of left upper jaw. Gill rakers stout, triangular, and widely spaced; 6-8 ceratobranchial and 2-3 epibranchial gill rakers on first gill arch. All specimens with 1 raker between the cerato-and epibranchial rakers.
Coloration of males.-Craniofacial region, from snout to preopercle, dark blue. Operculum grayish blue with bright metallic green opercular tab. Throat and branchiostegals white. Flank and caudal peduncle pale powder blue; 11 faint darker blue bars visible across flank and caudal peduncle. Dorsal and caudal fins whitish blue with yellow or orange trailing edges. Spinous anal fin pale orange; rayed portion white with 3-5 orange-yellow eggspots. Trailing portion of pelvic fin hyaline with white leading edge, and pale orange between.  In preservative, males uniformly dark brown or gray with 11 faint vertical bars visible across flank and caudal peduncle on some specimens.
Coloration of females.-Head, body, caudal peduncle uniformly light gray, with 11 faint dark bars extending across flank and caudal peduncle. Opercular tab black. Scales of flank and caudal peduncle with small orange spots close to insertion of scale. Throat and branchiostegals white. Dorsal fin white with orange tips; some specimens with orange spots throughout fin, some specimens with orange trailing edge. Caudal fin brownish gray, some specimens with orange trailing edge. Rayed anal fin pale brownish orange with 1-2 yellow eggspots; spinous portion white. Pelvic fin white or hyaline, with bright white leading edge and pale orange between.
In preservative, females uniformly dark brown or gray with 11 faint vertical bars visible across flank and caudal peduncle on some specimens.
Multivariate analyses.-Due to the overlap of morphometric and meristic characteristics between L. alticodia and the other Labeotropheus, we compared the body depth-standard length ratios of L. alticodia and its geographically proximate congeners (Fig. 3). This ratio clearly places L. alticodia with the robust Labeotropheus, and distinguishes it from L. trewavasae and the sympatric L. rubidorsalis, new species (Table 4). We also performed canonical discriminant function analyses on the meristic and Log 10 -transformed morphometric data. Both the morphometric and meristic canonical discriminant function analyses were robust and produced statistically significant results (Table 5). Labeotropheus alticodia is distinct from L. artatorostris and L. obscurus, new species, along the first morphometric canonical function and the first two meristic canonical functions, although there is minor overlap with L. fuelleborni (Fig. 4).
Distribution.-Labeotropheus alticodia is endemic to Lake Malaŵi and appears to be restricted to the Maleri Islands, specifically Maleri and Nankoma Islands, in Lake Malaŵi National Park, Malaŵi. We did not collect at the nearby Nakantenga Island, where Ribbink et al. (1983a) report a differently colored robust Labeotropheus.
Etymology.-The specific epithet combines the Latin adjective for deep or tall, alti, with a Latin word for head, specifically the head of a flower, codia, in reference to the striking head depth of this species.
Labeotropheus aurantinfra, Phiri and Pauers, new species urn:lsid:zoobank.org:act:68D4FDCB-80DF-44E2-977A-A7A7678CE748 Figures 5-7; Tables 6-9 Diagnosis.-Labeotropheus aurantinfra differs from all other Labeotropheus due to the extensive distribution of orange pigmentation throughout the body, including the maxilla, the preopercular margin, the branchiostegals, the gular and anterior abdomen region, and the flanks; although orange pigmentation is more common and more extensive in males, it is also present in the same body regions in females.
Description.-Morphometric and meristic data summarized in Table 6. Compressiform body with expanded ovoid shape; depth typical for a robust Labeotropheus (33.8-41.5% SL), and body consistently deep throughout its length. Body wide at pectoral fin and opercular tabs. Scales on belly and anterior abdomen cycloid and tightly crowded. Flank scales ctenoid; exposed portion of scale fan-shaped and approximately hexagonal. Anterior lateral line overlapping posterior lateral line by 0-3 scales. Dorsal fin long (56.3-62.9% SL); 17-19 spines and 7-9 rays. First dorsal spine anterior to or opposite opercular tab. Dorsal rays 3, 4, 5 long, reaching to hypural and beyond. Anal fin angular and kite-shaped. Anal rays 3, 4, 5 long in males, reaching past caudal peduncle to caudal fin; most female specimens with short anal-fin rays, reaching only to caudal peduncle. Anal-fin origin opposite dorsal-fin spine 14, 15, or 16; anal-fin insertion anterior to or opposite dorsal-fin insertion. Caudal fin subtruncate. Pectoral fin long and rounded, 12-14 rays. Pelvic fin long, minimally reaching origin of anal fin and longer in most specimens, especially in mature males; pelvic ray slightly produced and filamentous in all specimens. Pelvic-fin attachment opposite dorsal-fin spine 5 or 6.
Head short (29.1-38.8% SL) and deep with strongly curved profile and prominent snout; some specimens with concavity above eye. Snout long and wide, typical of Labeotropheus, with long snout pad (10.5-19.4% HL). Cheek deep with 3-4 scale rows. Infraorbital pores 8-10 with 15-67 neuromasts among them. Oral jaws short and wide. Oral teeth tricuspid and closely set on both upper and lower; 5-11 tricuspid teeth on lateral portion of left upper jaw. Gill rakers stout, triangular, and widely spaced; 7-10 ceratobranchial and 1-3 epibranchial gill rakers on first gill arch. All specimens with 1 raker between the cerato-and epibranchial rakers. Anal fin white or whitish gray with several (3-8) orange yellow eggspots. Pelvic fin pale red or orange with bright white leading edge; prominent black band separating leading edge from posterior color. In preservative, males uniformly dark brown or gray with 11 faint vertical bars across the flank and caudal peduncle on some specimens. Some individuals with brown spots or rings on scales of flank and ventrum.
Coloration of females.-Head, body, and caudal peduncle uniformly light gray, with 11 faint dark bars extending across flank and caudal peduncle. Opercular tab black with metallic green sheen. Orange pigmentation on maxilla, preopercular margin, branchiostegals, gular region, and anterior abdomen, though not as prominent as on males. Scales of flank and caudal peduncle with small orange spots close to insertion of scale. Throat and branchiostegals white. Dorsal fin whitish gray. Caudal fin brownish gray. Anal fin whitish gray with 1-2 yellow eggspots. Pelvic fin white or hyaline, with bright white leading edge and pale orange between. One female L. aurantinfra had an orange blotch ('OB') color pattern across entire body and all fins; ground color is pale orange with black, white, and darker orange spots of varying shape and size.
In preservative, females uniformly dark brown or gray with 11 faint vertical bars visible across the flank and caudal peduncle on some specimens. 'OB' female appears pale gray with black and white spots across body and fins.
Multivariate analyses.-Due to the overlap of morphometric and meristic characteristics between L. aurantinfra and the other Labeotropheus, we compared the body depth-standard length ratios of L. aurantinfra and its geographically proximate congeners (Fig. 6). This ratio clearly places L. alticodia with the robust Labeotropheus, and distinguishes it from the slender L. simoneae and L. chirangali, new species, as well as the intermediate L. chlorosiglos (Table 7). We also performed canonical discriminant function analyses on the meristic and Log 10 -transformed morphological data for L. aurantinfra, L. candipygia, new species, L. chlorosiglos, and L. fuelleborni. The canonical discriminant function analyses were robust and significant (Table 8). When the first morphometric canonical function is plotted against the first meristic canonical function, L. chlorosiglos is distinct along both axes, but there is some overlap among L. aurantinfra, L. candipygia, new species, and L. fuelleborni (Fig. 7A). Similarly, when the first two meristic canonical functions are plotted, L. chlorosiglos is distinct along meristic canonical function one, and L. fuelleborni is distinct along meristic canonical function two, with some overlap between L. aurantinfra and L. candipygia, new species (Fig. 7B).
Despite the overlap among L. aurantinfra, L. candipygia, new species, and L. fuelleborni along the canonical function axes, we found important distinctions among these species in the craniofacial region. Specifically, we examined the width to length ratios of both the lower jaw and snout. Labeotropheus aurantinfra, L. candipygia, new species, and L. fuelleborni all differ in these ratios (Fig. 8, Table 9).
Distribution.-Labeotropheus aurantinfra is endemic to Lake Malaŵi, along the Malaŵian shore. It appears to be restricted to Chirwa Island and the nearby Ndomo Gap, between the tip of the Luromo Peninsula and Chirwa Island.
Etymology.-The specific epithet is a composite of the Latin adjective aurantiacum, meaning orange colored, and a second Latin adjective, infra, meaning below or underneath. This is in reference to the unique male nuptial color pattern, in which the ventrum, anterior abdomen, and branchiostegals feature orange coloration.  All seven species; (B) same plot as A, but L. fuelleborni and L. trewavasae are omitted for clarity. The ANOVA accompanying these data is in Table  7.
peduncle to the ventral attachment of the caudal fin in some individuals. Above this silvery-white ventrum, males are ochreous orange, which covers most of the head and can extend to the base of the dorsal fin, and extends posteriorly through the caudal peduncle to the base of the caudal fin, or they will be a dull grayish blue with ochreous-orange highlights on the scales of the dorsum. Both color patterns feature a brilliantly iridescent white dorsal fin that has ochreous-orange tips and patches of iridescent blue, black, orange, or red pigmentation. Labeotropheus candipygia differs from the slender-bodied Labeotropheus, L. trewavasae, L. simoneae, L. chirangali, new species, except L. rubidorsalis, new species, due to its greater body depth (32.0-38.6% SL vs. 26.3-33.4% in L. trewavasae; 26.9-30.8% in L. simoneae; 26.6-33.2% in L. chirangali, new species); it does have a generally deeper body than L. rubidorsalis, new species, although the ranges overlap (31.6-36.1% in L. rubidorsalis, new species). It differs from L. rubidorsalis, new species, primarily in the nuptial coloration of the males, but also by a generally shorter snout length (19.7-33.9% HL vs. 29.8-42.7%), a longer snout pad (11.3-19.2% HL vs. mean 10.3-14.4%), and a greater number of tooth rows in the upper jaw (4-6 vs. 3-4).
Description.-Morphometric and meristic data summarized in Table 10. Body compressiform; ovoid shape. Body depth 32.0-38.6% SL; body consistently deep throughout its length. Body moderately wide at pectoral fin and opercular tab. Scales on belly and anterior abdomen cycloid and tightly crowded. Flank scales ctenoid; exposed portion of scale fanshaped and approximately hexagonal. Anterior lateral line overlapping posterior lateral line by 0-3 scales. Dorsal fin long, with 16-19 spines and 7-10 rays. Origin of dorsal fin anterior to or opposite opercular tab. Dorsal rays 3, 4, 5 long, reaching beyond hypural to caudal fin. Anal fin angular and kite-shaped. Anal rays 3, 4, 5 long in most males and some females, reaching past caudal peduncle to caudal fin; most female specimens with short anal-fin rays, reaching only to caudal peduncle. Anal-fin origin opposite dorsal-fin spine 14, 15, or 16; anal-fin insertion anterior to or opposite dorsal-fin insertion. Caudal fin subtruncate. Pectoral fin rounded, 13-15 rays. Pelvic fin long, minimally reaching origin of anal fin and longer in the majority of specimens. Pelvic-fin ray slightly produced and filamentous in all males and most  females; produced and non-filamentous in some females. Pelvic-fin attachment opposite dorsal-fin spine 4, 5, or 6. Head long (29.8-35.3% SL) and relatively shallow. Strongly curved profile with slight concavity above eye and prominent snout. Snout short but wide with long snout pad (11.3-19.2% HL). Cheek compact with 2-6 scale rows. Infraorbital pores 9 or 10 with 13-35 neuromasts among them. Oral jaws short and wide. Oral teeth tricuspid and closely set on both upper and lower jaws; 4-11 tricuspid teeth on lateral portion of left upper jaw. Gill rakers stout, triangular, and widely spaced; 6-10 ceratobranchial and 1-3 epibranchial gill rakers on first gill arch. All specimens with 1 raker between the cerato-and epibranchial rakers.
Coloration of males.-Ground color pale blue, fading to silvery blue or silvery white across ventral surface of head and flank; snout, jaws, operculum, throat, anterior abdomen, ventrum, and ventral portion of caudal peduncle all silvery blue or silvery white. All portions of head, operculum, flank, and caudal peduncle dorsal to the dorsal attachment of pectoral fin with ochreous-orange coloration; scales of flank and caudal peduncle either entirely ochreous orange or ringed with ochreous orange around pale blue or silvery blue center of scale. Opercular tab black, sometimes with faint greenish sheen. Ground color of dorsal-fin membrane silvery blue or silvery white, sometimes overlain by red patches throughout fin, or by ochreous-orange patches along proximal portion. Tips of dorsal fin ochreous orange. Caudal fin blue or silvery blue, grading to black posteriorly; thin orange trailing edge. Anal fin white or bluish white, with 3-5 orange-yellow eggspots. Pelvic fin pale red posteriorly with bright white leading edge; thick black band between white leading edge and posterior red color.
In preservative, males uniformly dark brown or gray with 11 faint vertical bars visible across flank and caudal peduncle on some specimens.
Coloration of females.-Head, body, and caudal peduncle uniformly light brown, with 11 faint dark bars extending across flank and caudal peduncle. Opercular tab black. Scales of flank and caudal peduncle with small orange spots close to insertion of scale. Throat and branchiostegals orange. Dorsal fin brownish gray with orange tips and orange trailing edge. Caudal fin brownish gray with thin orange trailing edge.
Anal fin brownish gray with 1-2 yellow eggspots and orange trailing edge. Pelvic fin pale orange posteriorly with bright white leading edge; thick black band between white leading edge and posterior orange color.
In preservative, females uniformly dark brown or gray with 11 faint vertical bars visible across flank and caudal peduncle on some specimens.
Multivariate analyses.-Due to the overlap of morphometric and meristic characteristics between L. candipygia and the other Labeotropheus, we compared the body depth-standard length ratios of L. candipygia and its geographically proximate congeners (Fig. 6). This ratio clearly places L. candipygia within the robust Labeotropheus, and distinguishes it from the slender L. simoneae and L. chirangali, new species, as well as the intermediate L. chlorosiglos (Table 7). We also performed canonical discriminant function analyses on the meristic and Log 10 -transformed morphological data for L. candipygia, L. chlorosiglos, L. fuelleborni, and the geographically proximate L. aurantinfra. The canonical discriminant function analyses were robust and significant (Table 8). While L. chlorosiglos is distinct along the first morphometric canonical function, and L. fuelleborni is particularly distinct along the second meristic canonical function, L. candipygia and L. aurantinfra overlap along all three canonical functions we plotted (Fig.  7). Despite the lack of resolution between L. candipygia and L. aurantinfra based upon the canonical discriminant function analyses, we found that L. candipygia has smaller width to length ratios of both the lower jaw and snout than both L. aurantinfra and L. fuelleborni (Fig. 8, Table 9).
Distribution.-Labeotropheus candipygia is endemic to the Malaŵian shore of Lake Malaŵi, and appears to be restricted to Chitende Island and the nearby Chitende Gap, between Chitende Point (the remnants of a peninsula that once connected Chitende Island to the mainland) and Chitende Island.
Remarks. -Ribbink et al. (1983a) state that they found the males of the robust Labeotropheus at Chitende Island to have a sky blue head, dorsum, and body, with an orange chest and dorsal fin. We did not find any robust Labeotropheus at Chitende matching this description; indeed, this description seems most similar to L. aurantinfra from Chirwa Island. Interestingly, they describe the slender Labeotropheus at Chitende as having coloration similar to that of L. candipygia (Ribbink et al., 1983a(Ribbink et al., , 1983b Table 9. , and a greater number of ceratobranchial gill rakers (7-10 vs. 5-8).
Description.-Morphometric data and meristic summarized in Table 11. Body compressiform and slender; body depth 27.5-30.3% SL. Flattened ovoid body shape, slightly deeper anteriorly than posteriorly. Body wide, slightly cylindrical in transverse cross section. Scales on belly and anterior abdomen cycloid and tightly crowded. Flank scales ctenoid; exposed portion of scale fan-shaped and approximately hexagonal. Anterior lateral line overlapping posterior lateral line by 0-3 scales. Dorsal fin of typical length for a Labeotropheus (55.8-61.3% SL), 18-19 spines and 8-9 rays. Origin of dorsal fin posterior to or overlapping opercular tab. Dorsal-fin rays 3, 4, 5 long, reaching to hypural and beyond to caudal fin. Anal fin angular anteriorly with slight rounding to membrane posteriorly. Origin of anal fin opposite dorsalfin spine 16; insertion of anal fin variable (anterior, opposite, or posterior) with respect to insertion of dorsal fin. Anal-fin rays 3, 4, 5 reach past hypural in most males; these only reach to mid-caudal peduncle in females. Caudal fin subtruncate. Pectoral fin short (19.3-24.7% SL), rounded, 13-14 rays. Pelvic fin long, minimally reaching origin of anal fin and longer in the majority of specimens. Pelvic-fin ray slightly produced and filamentous in males and females. Pelvic-fin attachment opposite dorsal-fin spine 4 or 5. Head short but deep for a slender Labeotropheus. Head profile moderately to strongly concave with prominent snout. Snout of typical length but wide (34.7-40.2% HL) with protruding snout pad (13.6-19.4% HL). Cheek with 3 scale rows. Infraorbital pores 9-10, with 14-38 neuromasts among them. Oral jaws long and wide. Oral teeth tricuspid and closely set on both upper and lower jaws; 6-11 tricuspid teeth on lateral portion of left upper jaw. Gill rakers stout, triangular, and widely spaced; 7-10 ceratobranchial and 1-3 epibranchial gill rakers on first gill arch. All specimens with 1 raker between the cerato-and epibranchial rakers.   Posterior portion of pelvic fin very pale orange with white leading edge; prominent black stripe between leading edge and posterior pigment. In preservative, males uniformly gray or brown with 11 dark bars spanning flank and caudal peduncle.
Coloration of females.-Head and operculum brown; opercular tab black with faint green sheen. Ground color of flank and caudal peduncle light tan; 11 dark brown bars span flank and caudal peduncle. Scales of flank and peduncle with small orange dot near insertion of scale. Belly white. Dorsal fin grayish brown or gray. Caudal fin gray; thin orange trailing edge. Spinous portion of anal fin white or gray, rayed portion grayish brown with orange trailing edge; 1-2 small orangeyellow eggspots present on rayed portion of anal fin. Pelvic fin pale orange with white leading edge; thin black bar separates leading edge from posterior pigment.
In preservative, females uniformly dark brown or gray with 11 faint vertical bars visible across flank and peduncle on some specimens.
Multivariate analyses.-Due to the overlap of morphometric and meristic characteristics between L. chirangali and the other geographically proximate slender Labeotropheus, we performed canonical discriminant function analyses on the meristic and Log 10 -transformed morphometric data of L. chirangali, L. simoneae, and L. trewavasae. These analyses were robust and significant (Table 12). When the first morphological canonical function is plotted against the first meristic canonical function, L. chirangali is clearly distinct from L. simoneae and L. trewavasae (Fig. 11).
Distribution.-Labeotropheus chirangali is endemic to the Malaŵian shore of Lake Malaŵi, and is known only from the Mphanga Rocks off the tip of the Luromo Peninsula along the northwestern shore of the lake.   Diagnosis.-Labeotropheus obscurus differs from all other species of Labeotropheus due to the unusually drab and muted coloration of sexually mature males; male nuptial   color pattern dominated by gray and brown pigmentation, with some blue and orange highlights on scales and fins, as opposed to a nuptial color pattern dominated by blue, orange, or red pigmentation. Labeotropheus obscurus differs from the slender-bodied Labeotropheus, L. trewavasae, L. simoneae, and L. chirangali, but not L. rubidorsalis, new species, due to its greater body depth . Labeotropheus obscurus typically has a greater body depth than L. rubidorsalis, new species, although the ranges slightly overlap (31.6-36.1% SL in L. rubidorsalis, new species). Overall, L. obscurus does have a deeper body than L. rubidorsalis, new species, as indicated by several other measurements akin to body depth, including the distance between the origin of the dorsal fin and the origin of the anal fin , the distance between the insertion of the dorsal fin and the insertion of the anal fin , the distance between the insertion of the dorsal fin and the origin of the anal fin (30.3-33.2% vs. 27.6-30.3%), and the distance between the origin of the dorsal fin and the attachment of the pelvic fins .
Description.-Morphometric and meristic data summarized in Table 13. Body compressiform; body shape ovoid. Body depth 35.2-41.5% SL and consistently deep throughout trunk. Body relatively narrow at pectoral fin and opercular tab. Scales on belly and anterior abdomen cycloid and tightly crowded. Flank scales ctenoid; exposed portion of scale fanshaped and approximately hexagonal. Anterior lateral line overlapping posterior lateral by 0-4 scales. Dorsal fin 56.1-63.0% SL, 16-18 spines and 7-9 rays. Origin of dorsal fin overlapping opercular tab. Dorsal-fin rays 3, 4, 5 long, reaching to hypural and beyond to caudal fin. Anal-fin shape variable; angular and kite-like in some (6 of 19) specimens, angled anteriorly with slight rounding to membrane posteriorly in others (13 of 19). Origin of anal fin opposite dorsal-fin spine 16 in majority of specimens; insertion of anal fin variable (anterior, opposite, or posterior) with respect to insertion of dorsal fin. Anal-fin rays 3, 4, 5 reach past hypural in most males; these only reach to midcaudal peduncle in females. Caudal fin subtruncate. Pectoral fin long (22.8-28.3% SL), rounded, with 13-15 rays. Pelvic fin long, minimally reaching origin of anal fin and longer in the majority of specimens. Pelvic-fin ray slightly produced and filamentous in all males and most females; pelvic-fin ray is non-filamentous in some females. Pelvic-fin attachment opposite dorsal-fin spine 5 or 6 in most specimens; opposite dorsal-fin spine 4 in one specimen.
Cheek with 3-4 scale rows. Infraorbital pores 9, with 22-46 neuromasts among them. Oral jaws long and narrow. Oral teeth tricuspid and closely set on both upper and lower jaws; 4-10 tricuspid teeth on lateral portion of left upper jaw. Gill rakers stout, triangular, and widely spaced; 6-11 ceratobranchial and 1-3 epibranchial gill rakers on first gill arch. All specimens with 1 raker between the cerato-and epibranchial rakers.
Coloration of males.-Ground color of head, operculum, flank, and caudal peduncle gray. Flank suffused with pale blue in some individuals; 11 darker bars extending across flank and peduncle visible in some individuals. Scales of flank abdominal to lateral line, between operculum and caudal peduncle, with orange spots near insertion of scale. Opercular tab black, overlain with metallic blue in some individuals. Dorsal fin gray in most individuals, pale blue in males with pale blue flanks; dorsal fin with orange tips and thin orange trailing edge in all individuals. Caudal fin gray with orange trailing edge. Anal fin predominantly gray with orange pigment on spinous portion; rayed portion with yellow tips and trailing edge, 2-4 orange-yellow eggspots present. Pelvic fin orange with white leading edge.
Preserved males uniformly brown or dark gray with 11 dark bars spanning flank and caudal peduncle visible on some individuals.
Coloration of females.-Head, body, and caudal peduncle uniformly light gray, with 11 faint dark bars extending across flank and caudal peduncle; some individuals suffused with a faint metallic green. Scales of flank and caudal peduncle with small orange spots close to insertion of scale. Opercular tab black. Throat and branchiostegals white. Dorsal fin white with orange tips; some specimens with orange trailing edge. Caudal fin brownish gray, some specimens with orange trailing edge. Rayed portion of anal fin pale brownish gray with 1-2 yellow eggspots; spinous portion white. Pelvic fin pale orange, with bright white leading edge.
In preservative, females uniformly dark brown or gray with 11 faint vertical bars visible across flank and caudal peduncle on some specimens.
Multivariate analyses.-Due to the overlap of morphometric and meristic characteristics between L. obscurus and the other Labeotropheus, we compared the body depth-standard length ratios of L. obscurus and its geographically proximate congeners (Fig. 3). This ratio clearly places L. obscurus with the robust Labeotropheus, and distinguishes it from L. trewavasae and L. rubidorsalis, new species (Table 4). We also performed canonical discriminant function analyses on the meristic and Log 10 -transformed morphometric data of L. alticodia, L. artatorostris, L. fuelleborni, and L. obscurus. Both the morphometric and meristic canonical discriminant function analyses were robust and produced statistically significant results (Table 5). Labeotropheus obscurus is distinct from L. artatorostris along the first morphometric canonical function and the first meristic canonical function (Fig. 4). It is additionally distinct from L. alticodia and L. fuelleborni along the second meristic canonical function (Fig. 4).
Distribution and abundance.-Labeotropheus obscurus is endemic to the Malaŵian shore of Lake Malaŵi, and is only known from Namalenje Island. Recently, it was reported that all Labeotropheus were possibly extirpated from Namalenje Island, as survey teams had not reported any occurrences of this genus at Namalenje Island for some time (TBP, pers. obs.). While we did both capture and observe Labeotropheus at Namalenje Island, females and juveniles were obvious and plentiful in the shallow regions, but males were found in deeper waters and were comparatively rare.
Etymology.-The specific epithet is the masculine form of the Latin adjective obscurus, meaning dark, dusky, or shadowy, in reference to the muted and mostly gray male nuptial color pattern, which is unusual for a species of Labeotropheus. Diagnosis.-Labeotropheus rubidorsalis differs from all other described species of Labeotropheus due to the nuptial color pattern of the males. The males have a vivid, almost metallic, blue head, body, and caudal peduncle, and an equally brilliant red dorsal fin. Labeotropheus rubidorsalis also differs from all other Labeotropheus by the shape of the anal fin. All other species of Labeotropheus have an angular to kite-shaped anal fin, but L. rubidorsalis has a distinctly rounded anal fin, especially in the posterior portion.
Labeotropheus rubidorsalis has a generally slenderer body than the most of the robust Labeotropheus, though its range   anterior to insertion of dorsal fin. Anal-fin rays 3, 4, 5 reach past hypural in males; only reach to mid-caudal peduncle in females. Caudal fin subtruncate. Pectoral fin long and rounded, with 13-15 rays. Pelvic fin long, minimally reaching origin of anal fin and longer in the majority of specimens. Pelvic-fin ray slightly produced and filamentous in half of specimens; non-filamentous in other half. Pelvicfin attachment opposite dorsal-fin spine 4, 5, or 6. Head long and deep, especially for a slender-bodied Labeotropheus; head depth 91.6-105.0% HL. Head profile moderately curved with no concavity above eye. Snout long and wide with slightly protruding snout; snout pad 10.3-14.2% HL. Cheek with 3-4 scale rows. Infraorbital pores 7-9, with 8-25 neuromasts distributed among them. Oral jaws long and wide. Oral teeth tricuspid and closely set on upper and lower jaws; 5-12 tricuspid teeth on lateral portion of left upper jaw. Gill rakers stout, triangular, and widely spaced; 5-8 ceratobranchial and 2-3 epibranchial gill rakers on first gill arch. All specimens with 1 raker between the cerato-and epibranchial rakers.
Coloration of males.-Head, operculum, flank, caudal peduncle brilliant, solid blue; 11 faint bars spanning flank and caudal peduncle. Opercular tab faint metallic green. Dorsal fin brilliant red, fading somewhat posteriorly; small hyaline spots in rayed dorsal fin. Caudal fin same brilliant blue as rest of body, fading posteriorly, with thin red trailing edge. Spinous portion of anal fin white, becoming blue in rayed portion; 3-5 yellow eggspots present. Pelvic fin bluish white posteriorly with white leading edge, pale red between.
Preserved males uniformly gray with 11 bars faintly visible across flank and caudal peduncle.
Coloration of females.-Females with orange blotch ('OB') color pattern across entire body and all fins; ground color is pale orange with black, white, and darker orange spots of irregular shape and varying size. Opercular tab black or black with faint green sheen. Anal fin hyaline in some individuals, some individuals with faint orange blotches overlying hyaline anal-fin membrane. All individuals with 1-7 very small orange eggspots present on anal fin. Preserved females uniformly white or pale gray with dark gray and/or black spots across flank and caudal peduncle.
Multivariate analyses.-Due to the overlap of morphometric and meristic characteristics between L. rubidorsalis and the other Labeotropheus, we compared the body depth-standard length ratios of L. rubidorsalis and its geographically proximate congeners (Fig. 3). This ratio shows that L. rubidorsalis has a body profile that is distinct from that of both the robust and slender Labeotropheus found nearby (Table 4). We also performed canonical discriminant function analyses on the meristic and Log 10 -transformed morphometric data of L. rubidorsalis and L. trewavasae. While the discriminant function analysis of the Log 10 -transformed morphometric data was not significant (Wilks' k ¼ 0.005, F 21,1 ¼ 9.109, P ¼ 0.26), the analysis of the meristic data was robust and significant (Table 15). When the first meristic canonical function is plotted as a histogram, L. rubidorsalis is clearly distinct from L. trewavasae (Fig. 14).
Distribution.-Labeotropheus rubidorsalis is endemic to the Malaŵian shore of Lake Malaŵi. We captured specimens at both Maleri and Nankoma Islands, in Lake Malaŵi National Park, and found a similarly colored slender Labeotropheus at Namalenje Island, but only captured two specimens and did not include these in our analyses; Ribbink et al. (1983a) also reported a similarly colored slender Labeotropheus from Namalenje. We did not collect at the nearby Nakantenga Island, where Ribbink et al. (1983a) reported a differently colored slender Labeotropheus.
Etymology.-The specific epithet is a combination of the Latin adjective rubi, meaning red colored, the Latin noun dorsum, meaning the dorsal surface or back, and the Latin suffix -alis, which means pertaining to. This epithet describes the brilliant red dorsal fin of the males.

DISCUSSION
The six species described herein more than double the number of known species of Labeotropheus and are thus a significant addition to the taxonomy of this genus. The inclusion of these new species is especially notable given that, until very recently, the existence of species beyond L. fuelleborni and L. trewavasae was considered virtually impossible (reviewed in Pauers, 2010). Nonetheless, Ribbink et al. (1983aRibbink et al. ( , 1983b had argued that the extensive geographic variation in male nuptial color pattern among populations of both L. fuelleborni and L. trewavasae was strong evidence for reproductive isolation among these populations, and that these differently colored, allopatric populations should be recognized as distinct species. Evidence from genetics (Arnegard et al., 1999), morphology (Pauers and McMillan, 2015;Albertson and Pauers, 2019), and behavior (Pauers et al., 2004;Pauers and McKinnon, 2012) was instrumental in providing support for re-evaluating the taxonomic status of these populations of Labeotropheus (Pauers, 2010(Pauers, , 2016(Pauers, , 2017. Although Labeotropheus and most of the other rockdwelling haplochromines of Lake Malaŵi are not currently considered to be threatened by the IUCN, recent publications have highlighted the threats to the continued existence of these nearshore species. Su et al. (2021) found that freshwater fishes throughout the world are vulnerable to a variety of anthropogenic stressors, exposure to which results in drastic declines in functional, taxonomic, and phylogenetic biodiversity. In Lake Malaŵi, the mbuna are at risk due to their close proximity to human settlements and activities, and their restricted distributions and stenotopic habits make them particularly susceptible to overexploitation by subsistence fishers (Kanyerere et al., 2019). Additionally, agricultural runoff degrades the rocky nearshore habitats by depositing silt and sediment on the lithophilic algae that serve as food for many of the mbuna, including Labeotropheus (Kanyerere et al., 2019). Interestingly, Kanyerere et al. (2019) concluded that increased and extensive taxonomic studies of the fishes of Lake Malaŵi is a vital component to their conservation and continued existence. Since the taxonomic status of many of these species, especially those with extensive geographic variation, is poorly understood, intensive ichthyological studies of these fishes could result in the description of new species. The elevation of these allopatric populations to species would allow them to be fully evaluated by the IUCN for Red List inclusion and concomitant protection. Our description of these six new Labeotropheus is thus an important first step in their conservation.
On the distinctions among Labeotropheus aurantinfra, L. chlorosiglos, and L. simoneae.-The islands and reefs surrounding the Luromo Peninsula seem to be a hotspot of biodiversity in the Labeotropheus. Given the close geographic proximity of these features, it is likely that the Labeotropheus that inhabit them are closely related (Arnegard et al., 1999). Although phylogeographic studies are necessary to confirm this, three of the species from this region, L. aurantinfra, L. chlorosiglos, and L. simoneae, reveal their possible evolutionary kinship through their strikingly similar color patterns. All three species have large orange patches along their flanks with a blue dorsum. Nonetheless, the finer details of their color patterns reveal consistent, diagnosable differences among these species (Fig. 15). For example, L. aurantinfra has extensive orange pigmentation on the ventral surface of the jaw, throat, and anterior abdomen, which is not found in L. chlorosiglos or L. simoneae; similarly, L. simoneae has orange patches on the operculum that are not found in the other two species. Additionally, these species differ in their bodily proportions, with L. aurantinfra having the largest body depth-standard length ratio, and L. simoneae the smallest. In the Labeotropheus, this ratio is associated with depth distribution, habitat preference, and foraging performance, and thus suggests important differences in the ecology of these species (Ribbink et al., 1983a(Ribbink et al., , 1983bPauers et al., 2018). These differences among these species should be explored further in studies of their natural history and sexually selected behavior.
We also take the opportunity to provide further information on the type locality of L. simoneae. Pauers (2016) reported its type locality as a ''submerged reef near Katale Island.'' During our 2018 expedition to the Luromo Peninsula, we located this reef and were able to identify it as Makankha Reef, located at -10.4666938, 34.2874299. We collected several specimens of L. simoneae at Makankha Reef, and a few specimens of L. chlorosiglos.
The genus Labeotropheus represents an exciting opportunity to put into action the recommendations of Kanyerere et al. (2019) regarding increased taxonomic attention to the cichlids of Lake Malaŵi. Through careful and exhaustive analyses of allopatric populations of Labeotropheus, we hope to not only increase our taxonomic knowledge of this genus, but also to contribute to the conservation of these unique and important fishes. Nonetheless, given the degree to which morphometric and meristic characteristics can overlap among the species of Labeotropheus, great care must be taken to record where the specimens were collected, as well as to describe the minute details of their color patterns.

DATA ACCESSIBILITY
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