|
Dorsal spines (total): 16-17; Dorsal soft rays (total): 9-10; Anal spines: 3-3; Anal soft rays: 7-9; Vertebrae: 30-30. Diagnosis: Orthochromis mporokoso can be readily distinguished from all species currently placed in Orthochromis and O. sp. "Igamba" from the Malagarasi drainage system by having more scale rows on cheek, 2-4 vs. 0-1 (Ref. 122085). Furthermore, O. mporokoso can be distinguished from O. kasuluensis, O. mosoensis, and O. rugufuensis by having more scales on operculum, 3-4 vs. 0-2; from O. kasuluensis by having fewer total vertebrae, 30 vs. 31-32; from O. rugufuensis by fewer dorsal-fin spines, 6-17 vs. 19; from O. mazimeroensis by more horizontal line scales, 29-30 vs. 26-28, more abdominal vertebrae, 14 vs. 12-13, and more total vertebrae, 30 vs. 28-29; from O. rubrolabialis and O. uvinzae by fewer dorsal-fin spines, 16-17 vs. 18-20; it has more total gill rakers than O. rubrolabialis, 10-12 vs. 8-9, and differs in position of pterygiophore supporting last dorsal-fin spine, vertebral count 16 vs. 17-18 (Ref. 122085). It differs from O. uvinzae additionally by having fewer scales between upper lateral line and dorsal-fin origin, 4-5 vs. 6-8, fewer abdominal vertebrae, 14 vs. 15-16, fewer total vertebrae, 30 vs. 31-33, position of pterygiophore supporting last dorsal-fin spine, vertebral count 16 vs. 18-19, position of pterygiophore supporting last anal-fin spine, vertebral count 14-15 vs. 16-17; from O. luongoensis and O. torrenticola by having fewer caudal vertebrae, 16 vs. 17-18, and total vertebrae, 30 vs. 31-33; from O. kalungwishiensis by having fewer total vertebrae, 30 vs. 31-33, and fewer horizontal line scales, 29-30 vs. 31-32; from O. torrenticola additionally by having fewer anal-fin spines, 3 vs. 4, and position of pterygiophore supporting last anal-fin spine, vertebral count 14-15 vs. 16-17 (Ref. 122085). It can be distinguished from O. stormsi and O. polyacanthus by having fewer scales between upper lateral line and dorsal-fin origin, 4-5 vs. 6-9; in addition, it is distinguished from O. stormsi by having more horizontal line scales, 29-30 vs. 26-28, more total vertebrae, 30 vs. 28-29, and fewer total gill rakers, 10-12 vs. 13-15; from O. polyacanthus by having more series of scales on cheek, 2-4 vs. 0, fewer dorsal-fin spines, 16-17 vs. 18-20, and in position of pterygiophore supporting last dorsal-fin spine, vertebral count 16 vs. 17-18, as in position of pterygiophore supporting last anal-fin spine, vertebral count 14-15 vs. 16-17 (Ref. 122085). Meristic values of O. mporokoso overlap with those of O. machadoi, but it can be readily distinguished by having more vertical bars on flanks, 13-15 vs. 9-10, which moreover extend mainly ventrally; those of O. machadoi extend mainly dorsally; in addition, it is distinguished in head mask pattern, i.e. V-shape nostril stripe in O. mporokoso vs. straight nostril stripe in O. machadoi; cheek stripe present vs. absent in O. machadoi (Ref. 122085). It differs from Schwetzochromis neodon by ahving more circumpeduncular scales, 16 vs. 12, fewer inner series of teeth, 1-3 vs. 4-6, and fewer dorsal-fin rays, 9-10 vs. 11-12; it differs from Haplochromis bakongo and Haplochromis moeruensis by having more horizontal line scales, 29-30 vs. 26-28, more caudal vertebrae, 16 vs. 12-15, and more total vertebrae, 30 vs. 26-29; additionally, it is distinguished from H. moeruensis by having more upper lateral line scales, 21-23 vs. 19-20; from H. bakongo by having more dorsal-fin spines, 16-17 vs. 14-15, and in position of pterygiophore supporting last dorsal-fin spine, vertebral count 16 vs. 13-14; and from H. snoeksi it is distinguished by having more abdominal vertebrae, 14 vs. 13, fewer caudal vertebrae, 16 vs. 17, more anal-fin rays, 7-9 vs. 5-6, more total gill rakers, 10-12 vs. 9, and in position of pterygiophore supporting last dorsal-fin spine, vertebral count 16 vs. 15, and position pterygiophore supporting last anal-fin spine, vertebral count 14-15 vs. 13 (Ref. 122085). Meristic values of O. mporokoso overlap with those of Haplochromis vanheusdeni, but it lacks eggspots, has a nostril stripe vs. absent in H. vanheusdeni, exhibits a cheek stripe vs. absent in H. vanheusdeni, and has a higher number of vertical bars on flank, 13-15 vs. 6-7 (Ref. 122085). It differs from O. kimpala by having fewer scales between upper lateral line and dorsal-fin origin, 4-5 vs. 6-7; from O. indermauri by having more series of scales on the cheek, 2-4 vs. 0-1, more caudal vertebrae, 16 vs. 14-15, and more total vertebrae, 30 vs. 28-29 (Ref. 122085). Meristic values of O. mporokoso overlap with those of O. katumbii but former differs by having more vertical bars on flank, 13-15 vs. 7-9, and by head mask pattern, cheek stripe present vs. absent in O. katumbii; meristic values of O. mporokoso overlap with those of O. gecki but former is distinguished by having much wide interorbital, 1.3-19.5% of head length vs. 9.6-12.9%, and by lacking eggspots on anal fin vs. present in O. gecki (Ref. 122085).
Description: Moderately slender species with maximum body depth of 24.7-29.3% of standard length, at level of dorsal-fin origin, slowly decreasing towards caudal peduncle; caudal peduncle rather elongated and moderately deep, ratio of caudal-peduncle length to depth 1.5-2.3 (Ref. 122085). Head length almost one third of standard length; dorsal head profile slightly curved without prominent nuchal gibbosity; eye diameter larger than interorbital width; jaws isognathous or slightly retrognathous; posterior tip of maxilla not reaching anterior margin of orbit but ending slightly before; lips not noticeably enlarged or thickened (Ref. 122085). Anterior bicuspid teeth of outer row in both upper and lower jaw large and closely set; posterior teeth becoming almost subequally bicuspid; towards corner of mouth teeth smaller and less closely set, may become unicuspid or weakly bicuspid especially in upper jaw; individual bicuspid teeth with minimally expanded brownish crown, cusps uncompressed and moderately widely set, major cusp with almost straight edge, and neck moderately slender to stout; outer row upper jaw with 31-44 teeth and outer row lower jaw with 23-33 teeth; larger specimens generally with more teeth; two or three, rarely one, inner upper and lower jaw tooth rows with small tricuspid teeth (Ref. 122085). Lower pharyngeal bone about 1.3 times wider than long with short anterior keel about 0.4 times length dentigerous area; dentigerous area of lower pharyngeal bone about 1.5 times wider than long, with 10+10 teeth along posterior margin and 7-8 teeth along midline; anterior pharyngeal teeth, towards keel, bevelled and slender; those of posterior row larger than anterior ones, bevelled, bicuspid, well-developed major and minor cusp; larges teeth medially situated in posterior row; teeth along midline slightly larger than more lateral ones (Ref. 122085). Total gill raker count 10-12, with two epibranchial, one angle, and 7-9 ceratobranchial gill rakers; most anterior ceratobranchial gill rakers very small, increasing in size towards cartilaginous plug; gill raker in angle slightly shorter than longest ceratobranchial raker and epibranchial gill rakers further decreasing in size (Ref. 122085). Dorsal fin with 16-17 spines and with 9-10 rays; first dorsal-fin spine always shortest; dorsal-fin base length between 50.2-55.6% of standard length; posterior end of dorsal-fin rays ending slightly before or at caudal fin base; posterior tip of anal fin ending slightly before caudal-fin base; caudal-fin outline subtruncate and fin composed of 26-29 rays, 16 principal caudal-fin rays and 10-13 procurrent caudal-fin rays; anal fin with three spines, third spine longest, and 7-9 rays; anal-fin base length between 15.2-20.1% of standard length; pectoral fin with 15-16 rays; pectoral-fin length between 21.6-25.7% of standard length, longest pectoral ray not reaching level of anus; first upper and lower pectoral-fin rays very short to short; pelvic fin with first spine thickly covered with skin and five rays; pelvic-fin base slightly posterior of pectoral-fin base; pelvic fin slightly longer than pectoral fin; longest pelvic-fin ray almost reaching anus, ending approximately 0.5-2 flank scale widths before (Ref. 122085). Two separate lateral lines; flank above and below lateral lines covered with comparatively large ctenoid to cycloid scales, especially in large specimens only few scales of ctenoid appearance; anterior dorsal and ventral flank area covered by cycloid scales; belly with comparatively small cycloid scales; chest covered with even smaller cycloid scales compared to belly squamation; chest to flank transition with larger cycloid scales; snout scaleless up to anterior margin of orbit; interorbital, nape, and occipital region with medium sized cycloid scales; cheeks covered by small cycloid scales; 2-4 scale rows on cheek; cycloid scales on operculum of variable size, small to medium sized, and shape, ovoid to circular; opercular blotch partially covered by medium sized scales, but posterior margin scaleless; 3-4 scales on horizontal line starting from edge of postero-dorsal angle of operculum to anterior edge of operculum; upper lateral line scales 21-23 and lower lateral line 9-11; horizontal line scales 29-30; caudal fin with 0-2 pored scales; upper and lower lateral lines separated by two scales; 3-5 scales between upper lateral line and dorsal-fin origin; anterior part of caudal fin covered with 4-5 vertical columns of small cycloid scales with median scales slightly larger; scaled area of caudal fin extended posteriorly especially at pper and lower area with minute, interradial scales, approximately up to one third of caudal fin; sixteen scales around caudal peduncle (Ref. 122085). A total of 30 vertebrae, excluding urostyle element, with 14 abdominal and 16 caudal vertebrae; the pterygiophore supporting last dorsal-fin spine is inserted between neural spines of 16th and 17th vertebra, counted from anterior to posterior; pterygiophore supporting last anal-fin spine is inserted between haemal spines of 15th and 16th vertebra, rarely between ribs of 14th and haemal spine of 15th vertebra; single predorsal bone present; hypurals 1 and 2 as well as hypuals 3 and 4 always fused into single seamless units (Ref. 12285).
Colouration: In life: body ground colouration pale brown to light grey; anterior flank with yellow to golden reticulated pattern which becomes less prominent at level of anus and stops at level of caudal peduncle; dark grey to brownish, interrupted midlateral band from operculum to just posterior caudal fin base, ending in mostly visible blotch; intensity midlateral band varies depending on mood often hardly visible; midlateral band crossed by 13-15 vertical bars, which extend mainly ventrally, hardly recognizable except for more distinct first 4-5 anterior bars; in some specimens dorsum with irregular dark brown areas, which sometimes connect with midlateral band; scales on, above and below midlateral band until level of anus with blackish-blue to greyish-blue centres; dorsum and caudal peduncle pale brown to light grey; chest and belly light beige; dorsal head surface pale brown to light grey; snout and cheek beige, ventrally brighter; branchiostegal membrane light beige; operculum beige to yellowish, sometimes with metallic turquoise speckles, a black opercular spot connecting with anterior extension of midlateral band, interrupted at level of preoperculum, ending in wel--pigmented blotch slightly anterior of eye; another dark grey to brownish element of variable form on ventral corner of operculum; cheek with small, dark grey to brownish vertical stripe of variable shape and intensity, extending to slightly below eye, not reaching eye; dark grey to brownish lachrymal stripe ending at posterior end upper lip; very thin, dark grey to brownish nostril stripe, sometimes interrupted, V-shaped, extending between nostrils; thin, dark grey to brownish interorbital stripe present; no distinct supraorbital stripe, but area just above eye somewhat darker than remaining dorsal head region; upper and lower lip beige to pale brown, lower margin of upper lip greyish, darker coloured, lower lip lighter than upper; dorsal-fin membrane transparent with orange maculae, sometimes arranged in inclined rows; maculae bordered with orange and outlined with black, especially in spinous part of fin; anal fin transparent to yellow, towards margin becoming more intensively coloured, no maculae or eggspots present; caudal fin yellowish to greyish with two or three rows of small yellow-orange maculae near fin base; outer caudal-fin rays with black margin; pectoral and pelvic fins transparent but rays yellowish to greyish (Ref. 122085). In alcohol: colouration and melanin patterns similar to live specimens, but due to the preservation procedure of specimens, they tend to lose original colouration, especially melanin patterns more intense than in live specimens; overall body ground colouration light brownish; dorsum darker than flank below midlateral band; chest and belly beige to yellowish-beige; branchiostegal membrane beige, along operculum and ventrally becoming reddish brown; dorsal head surface and dorsum brownish, ethmoidal region greyish brown; upper lip beige to light greyish anteriorly, lower lip beige; cheek beige to pale brownish; vertical stripe on cheek faint; operculum beige to pale brown greyish and with opercular spot as described above, brownish element on operculum less clearly defined than in live specimens and covering almost entire operculum; head mask brownish; midlateral band and vertical bars brownish and more intense, especially posterior bars; dorsal fin whitish to light greyish and margins outlined in black; maculae visible but less intense and greyish; anal fin whitish to beige; margins blackish outlined; caudal fin light whitish to beige; margins blackish outlined, small greyish speckles visible on membrane; pectoral fin and pelvic fin whitish to light grey (Ref. 122085). |